//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26399 SUBJECT: LIGO/Virgo S191213g: Upper limits from IceCube neutrino searches DATE: 19/12/13 05:04:48 GMT FROM: Raamis Hussain at IceCube IceCube Collaboration (http://icecube.wisc.edu/) reports: Searches [1,2] for track-like muon neutrino events detected by IceCube consistent with the sky localization of gravitational-wave candidate S191213g in a time range of 1000 seconds [3] centered on the alert event time (2019-12-13 04:25:48.142 UTC to 2019-12-13 04:42:28.142 UTC) have been performed. During this time period IceCube was collecting good quality data. No significant track-like events are found in spatial coincidence of S191213g calculated from the map circulated in the 1-Preliminary notice. IceCube's sensitivity assuming an E^-2 spectrum (E^2 dN/dE) to neutrino point sources within the locations spanned by the 90% spatial containment of S191213g ranges from 0.029 to 0.382 GeV cm^-2 in a 1000 second time window. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu [1] Bartos et al. arXiv:1810.11467 (2018) and Countryman et al.arXiv:1901.05486 (2019) [2] PoS(ICRC2019)918 and Braun et al., Astroparticle Physics 29, 299 (2008) [3] Baret et al., Astroparticle Physics 35, 1 (2011) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26400 SUBJECT: LIGO/Virgo S191213g: Global MASTER-Net observations report DATE: 19/12/13 05:07:53 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) started inspect of the LIGO/Virgo S191213g errorbox 889 sec after notice time and 1326 sec after trigger time at 2019-12-13 04:56:14 UT, with upper limit up to 16.7 mag. The observations began at zenith distance = 81 deg. The sun altitude is -36.3 deg. The galactic latitude b = -9 deg., longitude l = 13 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=11013 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1417 | 2019-12-13 04:56:14 | MASTER-IAC | (15h 25m 56.44s , +22d 03m 32.7s) | C | 180 | 16.7 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26401 SUBJECT: LIGO/Virgo S191213g: No counterpart candidates in INTEGRAL SPI-ACS prompt observation DATE: 19/12/13 05:24:34 GMT FROM: Diego Gotz at CEA Gotz Diego (AIM CEA/DAp, France), Alexander Lutovinov (IKI, Russia) V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland) J. Rodi (IAPS-Roma, Italy) A. Coleiro (APC, France) S. Mereghetti (INAF IASF-Milano, Italy) on behalf of the INTEGRAL multi-messenger collaboration: https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration Using INTEGRAL/SPI-ACS realtime data (following [1]) we have performed a search for a prompt gamma-ray counterpart of S191213g. At the time of the event (2019-12-13 04:34:08 UTC, hereafter T0), INTEGRAL was operating in nominal mode. The peak of the event localization probability was at an angle of 99 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (7.4% of optimal) response of ISGRI, strongly suppressed (34% of optimal) response of IBIS/Veto, and somewhat suppressed (40% of optimal) response of SPI-ACS. The background within +/-300 seconds around the event was very stable (excess variance 1.1). We have performed a search for any impulsive events in INTEGRAL SPI- ACS (as described in [2]) data. We do not detect any significant counterparts and estimate a 3-sigma upper limit on the 75-2000 keV fluence of 5.2e-07 erg/cm^2 (within the 50% probability containment region of the source localization) for a burst lasting less than 1 s with a characteristic short GRB spectrum (an exponentially cut off power law with alpha=-0.5 and Ep=600 keV) occurring at any time in the interval within 300 s around T0. For a typical long GRB spectrum (Band function with alpha=-1, beta=-2.5, and Ep=300 keV), the derived peak flux upper limit is ~5.2e-07 (8e-08) erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range. For the mean reported distance 195.0 Mpc this corresponds to the limit on the total isotropic equivalent energy in 1 s of 2.4e+48 erg for the short GRB spectrum and for a long GRB spectrum isotropic equivalent luminosity in 1 s (8 s) of 1.1e+48 erg/s (3.6e+47 erg/s) We report for completeness and in order of FAP, all excesses identified in the search region. We find: 4 likely background excesses: scale | T | S/N | luminosity ( x 1e+48 erg/s) | FAP 3.75 | 67 | 3.8 | 14.6 +/- 5.37 +/- 11.6 | 0.076 5 | -222 | 4.6 | 15 +/- 4.65 +/- 11.9 | 0.084 4.3 | 89.8 | 3.5 | 12.3 +/- 5.01 +/- 9.76 | 0.159 1.1 | 15.2 | 3.1 | 23.3 +/- 9.93 +/- 18.5 | 0.226 Note that FAP estimates (especially at timescales above 2s) may be possibly further affected by enhanced non-stationary local background noise. This list excludes any excesses for which FAP is close to unity. All results quoted are preliminary. This circular is an official product of the INT EGRAL Multi-Messenger team. [1] Savchenko et al. 2017, A&A 603, A46 [2] Savchenko et al. 2012, A&A 541A, 122S //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26402 SUBJECT: LIGO/Virgo S191213g: Identification of a GW compact binary merger candidate DATE: 19/12/13 05:38:52 GMT FROM: Geoffrey Mo at LIGO The LIGO Scientific Collaboration and the Virgo Collaboration report: We identified the compact binary merger candidate S191213g during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2019-12-13 04:34:08.142 UTC (GPS time: 1260246866.142). The candidate was found by the GstLAL [1] analysis pipeline. S191213g is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.5e-08 Hz, or about one in 10 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S191213g The classification of the GW signal, in order of descending probability, is BNS (77%), Terrestrial (23%), BBH (<1%), MassGap (<1%), or NSBH (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object has a mass < 3 solar masses (HasNS) is >99%. Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is >99%. During the time period that the candidate signal was in band of the detector, multiple cases of scattered light glitches were present in both the H1 and L1 detectors, overlapping the frequency band of the candidate. These artifacts may have impacted the estimated significance and sky position of the event. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.fits.gz,0, an initial localization generated by BAYESTAR [2], distributed via GCN notice about 5 minutes after the candidate event time. * bayestar.fits.gz,1, an initial localization generated by BAYESTAR [2], distributed via GCN notice about 11 minutes after the candidate event time. The preferred sky map at this time is bayestar.fits.gz,1. For the bayestar.fits.gz,1 sky map, the 90% credible region is 1393 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 195 +/- 59 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo Public Alerts User Guide . [1] Messick et al. PRD 95, 042001 (2017) [2] Singer & Price PRD 93, 024013 (2016) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26403 SUBJECT: LIGO/Virgo S191213g: Coverage and upper limits from MAXI/GSC observations DATE: 19/12/13 06:35:49 GMT FROM: Hitoshi Negoro at Nihon U S. Sugita, M. Serino (AGU), N. Kawai (Tokyo Tech), H. Negoro (Nihon U.), M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi, R. Takagi (Nihon U.), T. Mihara, C. Guo, Y. Zhou, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, H. Nishida, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.), M. Shidatsu (Ehime U.), M. Oeda, K. Shiraishi (Tokyo Tech), S. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, R. Shimomukai, M. Tominaga (JAXA), Y. Ueda, A. Tanimoto, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake (Kyoto U.), H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.), M. Yamauchi, S. Iwahori, Y. Kurihara, K. Kurogi, K. Miike (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after the LVC trigger S191213g at 2019-12-13 04:34:08.142 UTC (GCN 26402). At the trigger time of S191213g, the high-voltage of MAXI/GSC was on, but the FOV was out of the 90% credible region of the bayestar skymap. The first one-orbit (92 min) scan observation with GSC after the event covered 92% of the 90% credible region of the bayestar skymap from 05:10:08 to 05:33:32 UTC (T0+2160 to T0+3564 sec). No significant new source was found in the region in the one-orbit scan observation. A typical 1-sigma averaged upper limit obtained in one scan observation is 20 mCrab at 2-20 keV. If you require information about X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26404 SUBJECT: LIGO/Virgo S191213g : no neutrino counterpart candidate in ANTARES search DATE: 19/12/13 06:50:45 GMT FROM: Damien Dornic at CPPM,France M. Ageron (CPPM/CNRS), B. Baret (APC/CNRS), A. Coleiro (APC/Universite de Paris), M. Colomer (APC/Universite de Paris), D. Dornic (CPPM/CNRS), A. Kouchner (APC/Universite de Paris), T. Pradier (IPHC/Universite de Strasbourg) report on behalf of the ANTARES Collaboration: Using on-line data from the ANTARES detector, we have performed a follow-up analysis of the recently reported LIGO/Virgo S191213g event using the 90% contour of the Initial bayestar probability map provided by the GW interferometers (GCN#26402). The ANTARES visibility at the time of the alert, together with the 50% and 90% contours of the probability map are shown at http://antares.in2p3.fr/GW/S191213g_Initial.png . Considering the location probability provided by the LIGO/Virgo collaborations, there is a 75.1% chance that the GW emitter was in the ANTARES **upgoing** field of view at the time of the alert. No up-going muon neutrino candidate events were recorded in the ANTARES sky during a +/-500s time-window centered on the time 2019-12-13 04:34:08 and in the 90% contour of the S191213g event. The expected number of atmospheric background events in the region visible by ANTARES is 7.41e-04 in the +/- 500s time window. An extended search during +/- 1 hour gives no up-going muon neutrino coincidence. The expected number of atmospheric background events in the region visible by ANTARES is 5.33e-03 in this larger time window. ANTARES is the largest undersea neutrino detector, installed in the Mediterranean Sea, and it is primarily sensitive to neutrinos in the TeV-PeV energy range. At 10 TeV, the median angular resolution for muon neutrinos is about 0.5 degrees. In the range 1-100 TeV ANTARES has a competitive sensitivity to this position in the sky. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26407 SUBJECT: LIGO/Virgo S191213g: upper limits from AGILE-MCAL observations DATE: 19/12/13 07:56:24 GMT FROM: Claudio Casentini at INAF-IAPS F. Verrecchia (SSDC, and INAF/OAR), C. Casentini (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, G. Piano, A. Ursi (INAF/IAPS), F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia (INAF/OA-Cagliari), F. Longo (Univ. Trieste, and INFN Trieste), report on behalf of the AGILE Team: In response to the LIGO/Virgo GW event S191213g at T0 = 2019-12-13 04:34:08.142 (UT), a preliminary analysis of the AGILE minicalorimeter (MCAL) triggered data found no event candidates within a time interval covering -/+ 15 sec from the LIGO/Virgo T0. At the T0, about 60% of the S191213g 90% c.l. localization region was accessible to the AGILE MCAL.Three-sigma upper limits (ULs) are obtained for a 1 s integration time at different celestial positions within the accessible S191213g localization region, from a minimum of 1.8E-06 erg cm^-2 to a maximum of 8.1E-06 erg cm^-2 (assuming as spectral model a single power law with photon index 1.5). The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the energy range 0.4-100 MeV. Additional analysis of AGILE data is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26408 SUBJECT: LIGO/Virgo S191213g: upper limits from AGILE-GRID observations DATE: 19/12/13 09:03:46 GMT FROM: Francesco Verrecchia at ASDC C. Casentini (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, G. Piano, A. Ursi (INAF/IAPS), F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia (INAF/OA-Cagliari), F. Longo (Univ. Trieste, and INFN Trieste), report on behalf of the AGILE Team: In response to the LIGO-Virgo GW event S191213g at T0 = 2019-12-13 04:34:08.142 UTC a preliminary analysis of the AGILE exposure at T0 shows that the Gamma-Ray Imaging Detector (GRID) exposure covered about 11% of the 90% c.l. localization region (LR; 36% of 90% c.l. LR is occulted by Earth). We performed an analysis of the GRID data in the energy range 50 MeV - 10 GeV on T0, where good exposure of the S191213g 90% c.l. LR was available. No candidate gamma-ray transient was detected. The following preliminary GRID values of 3-sigma upper limit (UL) are obtained: from 4.0e-06 to 9.9e-06 erg cm^-2 s^-1, with exposure of about 11% of the LR over the time interval ( T0 -2s ; T0 + 2s ); from 1.6e-06 to 9.4e-06 erg cm^-2 s^-1, with exposure of about 16% of the LR over the time interval ( T0s ; T0 + 10s ); from 4.9e-08 to 6.3e-07 erg cm^-2 s^-1, with exposure of about 34% of the LR over the time interval ( T0s ; T0 + 100s ); These measurements were obtained with AGILE observing a large portion of the sky in spinning mode. Additional analysis of AGILE data is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26409 SUBJECT: LIGO/Virgo S191213g: Upper limits from Fermi-GBM Observations DATE: 19/12/13 13:56:20 GMT FROM: Colleen A. Wilson at NASA/MSFC/NSSTC C.A. Wilson-Hodge (NASA/MSFC) reports on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group For S191213g and using the initial bayestar.fits.gz skymap, Fermi-GBM was observing 99.9% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo detection of GW trigger S191213g (GCN 26402). An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates. We therefore set upper limits on impulsive gamma-ray emission. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2): Timescale soft norm hard -------------------------------------- 0.128 s: 5.4 8.9 14. 1.024 s: 2.1 2.8 6.3 8.192 s: 0.63 0.96 1.6 Assuming the median luminosity distance of 194.9 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^48 erg/s): Timescale Soft Normal Hard ------------------------------------ 0.128 s: 3.7 5.7 15. 1.024 s: 1.5 1.8 6.7 8.192 s: 0.44 0.62 1.7 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26410 SUBJECT: LIGO/Virgo S191213g: no counterpart candidates in the Swift/BAT observations DATE: 19/12/13 15:38:30 GMT FROM: Amy Lien at GSFC S. D. Barthelmy (NASA/GSFC), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), T. Sakamoto (AGU), A. P. Beardmore (U. Leicester), M. G. Bernardini (INAF-OAB), A. A. Breeveld (MSSL-UCL), D. N. Burrows (PSU), S. Campana (INAF-OAB), S. B. Cenko (NASA/GSFC), G. Cusumano (INAF-IASF PA), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), V. D'Elia (ASI-ASDC), S. Emery (UCL-MSSL), P. A. Evans (U. Leicester), P. Giommi (ASI), C. Gronwall (PSU), D. Hartmann (Clemson U.), J. A. Kennea (PSU), N. Klingler (PSU), H. A. Krimm (NSF), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), J. A. Nousek (PSU), S. R. Oates (Uni. of Warwick), P. T. O'Brien (U. Leicester), J. P. Osborne (U. Leicester), C. Pagani (U. Leicester), K. L. Page (U.Leicester), M. J. Page (UCL-MSSL), M. Perri (ASDC), J. L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU), G. Tagliaferri (INAF-OAB), A. Tohuvavohu (Toronto), E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team: We report the search results in the BAT data within T0 +/- 100 s of the LVC event S191213g (LIGO/VIRGO Collaboration GCN Circ. 26402), where T0 is the LVC trigger time (2019-12-13T04:34:08.142 UTC). The center of the BAT field of view (FOV) at T0 is RA = 292.787 deg, DEC = 16.993 deg, and the roll angle is 209.750 deg. The BAT FOV (>10% partial coding) covers 76.98% of the integrated LVC localization probability, and 80.29% of the galaxy convolved probability (Evans et al. 2016). Note that the sensitivity in the BAT FOV changes with the partial coding fraction. Please see the BAT FOV figure in the summary page (link below) for the specific location of the LVC region relative to the BAT FOV. Within T0 +/- 100 s, no significant detections (signal-to-noise ratio >~ 5 sigma) are found in the BAT raw light curves with time bins of 64 ms, 1 s, and 1.6 s. Assuming an on-axis (100% coded) short GRB with a typical spectrum in the BAT energy range (i.e., a simple power-law model with a power-law index of -1.32, Lien & Sakamoto et al. 2016), the 5-sigma upper limit in the 1-s binned light curve corresponds to a flux upper limit (15-350 keV) of ~ 7.7 x 10^-8 erg/s/cm^2. Assuming a luminosity of ~ 2 x 10^47 erg/s (similar to GW170817) and an average Epeak of ~ 400 keV for short GRBs (Bhat et al. 2016), this flux upper limit corresponds to a distance of ~ 82 Mpc. No event data are available around T0 +/- 100 s. BAT retains decreased, but significant, sensitivity to rate increases for gamma-ray events outside of its FOV. About 22.90% of the integrated LVC localization probability was outside of the BAT FOV but above the Earth's limb from Swift's location, and the corresponding flux upper limits for this region are within roughly an order of magnitude higher than those within the FOV. The results of the BAT analysis are available at https://swift.gsfc.nasa.gov/results/BATbursts/team_web/S191213g/web/source_public.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26412 SUBJECT: LIGO/Virgo S191213g: No counterpart candidates in Fermi-LAT observations DATE: 19/12/13 16:18:14 GMT FROM: Sara Cutini at INFN S. Cutini (INFN Perugia), N. Omodei (Stanford Univ.), M. Axelsson (KTH & Stockholm Univ,), E. Bissaldi (Politecnico & INFN Bari), D. Kocevski (NASA/MSFC), F.Longo (University and INFN, Trieste) and M. Arimoto (Kanazawa Univ.) report on behalf of the Fermi-LAT Collaboration: We have searched data collected by the Fermi Large Area Telescope (LAT) on December 13th, 2019, for possible high-energy (E > 100 MeV) gamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo trigger S191213g (GCN 26402). We define "instantaneous coverage" as the integral over the region of the LIGO probability map that is within the LAT field of view at a given time, and "cumulative coverage" as the integral of the instantaneous coverage over time. Fermi-LAT had an instantaneous coverage of 80% of the LIGO probability at the time of the trigger (T0 = 2019-12-13 04:34:08.142 UTC), and reached 100% cumulative coverage after 4.5 ks We performed a search for a transient counterpart within the observed region of the 90% contour of LIGO map in a fixed time window from T0 to T0 + 10 ks. No significant new sources are found. We also performed a search which adapted the time interval of the analysis to the exposure of each region of the sky, and no additional excesses were found. Energy flux upper bounds for the fixed time interval between 100 MeV and 1 GeV for this search vary between ~2e-10 and ~2e-07 [erg/cm^2/s]. The Fermi-LAT point of contact for this event is Sara Cutini (sara.cutini@pg.infn.it) The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26417 SUBJECT: LIGO/Virgo S191213g: Updated Sky Localization DATE: 19/12/14 02:01:39 GMT FROM: Geoffrey Mo at MIT The LIGO Scientific Collaboration and the Virgo Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S191213g (GCN Circular 26402). Parameter estimation has been performed using LALInference [1] and a new sky map, LALInference.fits.gz, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S191213g The preferred sky map at this time is LALInference.fits.gz. For the LALInference.fits.gz sky map, the 90% credible region is 4480 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 201 +/- 81 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo Public Alerts User Guide . [1] Veitch et al. PRD 91, 042003 (2015) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26419 SUBJECT: LIGO/Virgo S191213g: No transient candidates in CALET observations DATE: 19/12/14 05:11:12 GMT FROM: Yuta Kawakubo at Louisiana State U./CALET P. S. Marrocchesi (U of Siena), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), and the CALET collaboration: The CALET Gamma-ray Burst Monitor (CGBM) was operating at the trigger time of S191213g T0 = 2019-12-13 04:34:08.142 UT (The LIGO Scientific Collaboration and Virgo Collaboration, GCN Circ. 26402). No CGBM on-board trigger occurred around the event time. Based on the LVC high probability localization region, the summed LIGO probabilities inside the CGBM HXM (7 - 3000 keV) and SGM (40 keV - 28 MeV) fields of view are 0 % and 6 %, respectively (and 33 % credible region of the initial localization map was above the horizon). The HXM and SGM fields of view were centered at RA = 27.7 deg, Dec = -2.5 deg and RA = 20.4 deg, Dec = -9.3 deg at T0, respectively. Based on the analysis of the light curve data with 0.125 sec time resolution from T0-60 sec to T0+60 sec, we found no significant excess (signal-to-noise ratio >= 7) around the trigger time in either the HXM or the SGM data. The CALET Calorimeter (CAL) was operating in the high energy trigger mode at the trigger time of S191213g. Using the CAL data, we have searched for gamma-ray events in the 10-100 GeV band from -60 sec to +60 sec from the GW trigger time and found no candidates. There is no significant overlap with the LVC high probability localization region at T0+-60 sec. The CAL FOV was centered at RA=20.4 deg, Dec=-9.3 deg at T0. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26423 SUBJECT: LIGO/Virgo S191213g: No neutrino candidates at Pierre Auger Observatory DATE: 19/12/14 11:11:29 GMT FROM: Jaime Alvarez-Muniz at Pierre Auger Observatory J. Alvarez-Muniz, F. Pedreira, E. Zas (IGFAE & University of Santiago de Compostela, Spain), K. H. Kampert & M. Schimp (University of Wuppertal, Germany) on behalf of the Pierre Auger Collaboration. In response to: LIGO/Virgo GW trigger S191213g T0=2019-12-13 04:34:08 UTC We searched for Ultra-High-Energy (UHE) neutrinos with energies above ~ 1e17 eV in data collected with the Surface Detector (SD) of the Pierre Auger Observatory in a [-500,500] second interval about the LIGO-Virgo trigger S191213g as well as in a 24 hr time interval following the event. NO events survived the cuts applied to reject the background due to UHE Cosmic Rays i.e. NO neutrino candidates were detected. The field of view (fov) where the SD of Auger is sensitive to UHE neutrinos (corresponding to inclined directions with respect to the vertical relative to the ground) was PARTIALLY COINCIDENT (16.5%) at the time T0 of the merger alert, with the latest LIGO/Virgo 90% localization region (LALInference.fits.gz updated on Dec 14, 2019 00:59:57 UTC), achieving a MAXIMUM OVERLAP (59.9%) at approximately T0+6.93 hours. ------- The Pierre Auger Observatory is an UHE Cosmic Ray detector located in the Mendoza Province in Argentina. It consists of an array of Water Cherenkov detectors spread over a total surface of 3000 km^2 arranged in a triangular grid of 1.5 km side as well as Fluorescence telescopes and other systems (see 10.1016/j.nima.2015.06.058 for more information). For neutrino searches with Auger, please refer to: https://iopscience.iop.org/article/10.1088/1475-7516/2019/10/022 https://iopscience.iop.org/article/10.1088/1475-7516/2019/11/004 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26424 SUBJECT: LIGO/Virgo S191213g: Candidates from the Zwicky Transient Facility DATE: 19/12/14 11:22:07 GMT FROM: Igor Andreoni at Caltech Igor Andreoni (Caltech), Shreya Anand (Caltech), Eric Bellm (UW), Erik Kool (OKC), Dan Perley (LJMU), Leo Singer (NASA/GSFC), Michael Coughlin (Caltech), Tomas Ahumada (UMD), Harsh Kumar (IIT-B), Mansi M. Kasliwal (Caltech) We observed the localization region of the gravitational wave trigger S191213g (LVC, GCN #26402) with the Palomar 48-inch telescope equipped with the 47 square degree Zwicky Transient Facility camera (ZTF, Bellm et al. 2019, Graham et al. 2019). The tiling was optimally determined and triggered using the GROWTH Target of Opportunity marshal (Coughlin et al. 2019a, Kasliwal et al. 2019b). We started obtaining target-of-opportunity observations in the g-band and r-band beginning at 2019-12-14 03:47 UT, covering 29% of the enclosed probability based on the new LALInference skymap (LVC, GCN #26417). Each exposure was 180s with a median depth of 20.3 mag. The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts (Masci et al. 2019). Alert filtering and follow-up coordination was undertaken by the GROWTH Marshal system (Kasliwal et al. 2019). The ZTF alert stream was also queried using the Kowalski infrastructure (Duev et al., 2019). We required at least 2 detections separated by at least 30 minutes to select against moving objects. Furthermore, we cross-matched our candidates with the Minor Planet Center to flag known asteroids. Candidates that passed our selection are: +--------------+-----------+-------------+--------------+--------+------+----------+-------+ | Name | IAU Name | RA | Dec | filter | mag | MJD | Class | +--------------+-----------+-------------+--------------+--------+------+----------+-------+ | ZTF19acykzsk | -- | 02:11:37.09 | +34:02:28.85 | r | 18.9 | 58831.31 | | | ZTF19acymaru | AT2019wnh | 05:21:50.87 | -19:15:59.04 | g | 19.9 | 58831.36 | | | ZTF19acykzsp | AT2019wne | 01:53:26.19 | +31:48:03.64 | g | 20.2 | 58831.17 | | | ZTF19acyfoha | AT2019wkl | 05:40:25.05 | -18:05:51.47 | r | 17.5 | 58831.26 | SN Ia | | ZTF19acymgzk | AT2019vtj | 02:17:03.24 | +45:51:59.87 | r | 17.9 | 58831.32 | | | ZTF19acymcwv | AT2019wni | 02:24:59.74 | +47:29:52.24 | r | 20.1 | 58831.30 | | | ZTF19acykwsd | AT2019wnl | 02:12:21.14 | +41:23:19.35 | g | 19.4 | 58831.14 | | | ZTF19acylvus | AT2019wnk | 05:34:31.47 | -19:25:12.88 | g | 19.4 | 58831.35 | | | ZTF19acymcna | AT2019wnn | 02:12:49.90 | +40:59:59.01 | r | 20.7 | 58831.32 | | +--------------+-----------+-------------+--------------+--------+------+----------+-------+ ZTF19acykzsk is interesting because it shows red color (g-r=0.3), it is less than 2 days old and it has an absolute magnitude of -15.5 mag. Upper limits from last night are r>19.85 and g>19.5 on 2019-12-13 05:37 and 2019-12-13 04:26 respectively. We could not report this candidate to TNS as it is less than 5 arcsec from an unrelated transient in 2018 (AT2018fua). The host distance is within 2-sigma of the GW distance estimate. Follow-up of ZTF19acykzsk is encouraged. ZTF19acymaru/AT2019wnh appears to be located 25.3" from the 2MASX05215209-1915406 galaxy 225 Mpc away (GLADE catalog, Dalya et al., 2016), so within one sigma of the GW distance estimate. ZTF19acykzsp/AT2019wne does not show rapid evolution in r band in 1 day and its g-r color is consistent with zero. The photometric redshift from Sloan Digital Sky Survey is z = 0.18 +- 0.02 (Alam et al., 2015). ZTF19acyfoha/AT2019wkl was observed with Palomar 60-inch telescope equipped with the SED Machine instrument. The spectrum is consistent with the spectrum of a Type Ia supernova at redshift 0.044. ZTF19acymgzk/AT2019vtj appears to have a host with unknown redshift. The g-r color is consistent with zero and there are no meaningful upper limits prior discovery in ZTF data. ZTF19acymcwv/AT2019wni appears to be in a galaxy cluster at redshift z=0.113 (NED). Color information is not available for this candidate and non-detections prior to discovery are not constraining. ZTF19acykwsd/AT2019wnl appears hostless, has the last non-detection on 2019-12-13 and its g-r color is consistent with zero. ZTF19acylvus/AT2019wnk has a host galaxy, rose by 0.3 mag in r-band over one night and has a g-r color of 0.1. ZTF19acymcna/AT2019wnn is located on top of the nucleus of a galaxy with cataloged redshift of z=0.13775 (GLADE, Dalya et al., 2016). ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert filtering and follow-up coordination is being undertaken by the GROWTH marshal system (Kasliwal et al. 2019). Alert database searches are done with using the Kowalski infrastructure (Duev et al., 2019) and with AMPEL (Nordin et al. 2019). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26425 SUBJECT: LIGO/Virgo S191213g: AstroSat CZTI upper limits DATE: 19/12/14 11:31:31 GMT FROM: Varun Bhalerao at Indian Inst of Tech V. Shenoy (IITB), Aarthy E. (PRL), V. Bhalerao (IITB), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: We have carried a search for X-ray candidates in Astrosat CZTI data in a 100 sec window around the trigger time of the BNS merger event S191213g (UTC 2019-12-13 04:34:08.000, GraceDB event). CZTI is a coded aperture mask instrument that has considerable effective area for about 29% of the entire sky, but is also sensitive to brighter transients from the entire sky. At the time of merger, Astrosat's nominal pointing is RA,DEC = 10:45:07.6,-59:44:34.1 (161.2817,-59.7428), which is 85 deg away from the maximum probability location. At the time of merger event, the Earth-satellite-transient angle corresponding to maximum probability location is ~ 90.84 deg and hence is not occulted by Earth in satellite's frame. In a time interval of 100 sec around the event, the region of the LALInference localisation map which is not occulted by Earth in the satellite's frame has a cumulative probability of 0.8 (80%). CZTI data were de-trended to remove orbit-wise background variation. We then searched data from the four independent, identical quadrants to look for coincident spikes in the count rates. Searches were undertaken by binning the data in 0.1s, 1s, and 10s respectively. Statistical fluctuations in background count rates were estimated by using data from 10 (+-5) neighbouring orbits. We selected confidence levels such that the probability of a false trigger in a 1000 sec window is 10^-4. We do not find any evidence for any hard X-ray transient in this window, in the CZTI energy range of 20-200 keV. We use a detailed mass model of the satellite to calculate the direction-dependent instrument response for points in the visible sky. We then assume the source is modelled as a power law with photon index alpha = -1, and convert our count rate upper limits to direction-dependent flux limits. We obtain the following upper limits for source flux in the 20-200 keV band by taking a probability weighted mean over the visible sky: 0.1 s: flux limit= 1.69e-05 ergs/cm^2/s; fluence limit = 1.69e-06 ergs/cm^2 1.0 s: flux limit= 5.07e-06 ergs/cm^2/s; fluence limit = 5.07e-06 ergs/cm^2 10.0 s: flux limit= 6.72e-07 ergs/cm^2/s; fluence limit = 6.72e-06 ergs/cm^2 CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26426 SUBJECT: LIGO/Virgo S191213g: Liverpool Telescope spectroscopy of ZTF candidates DATE: 19/12/14 21:56:23 GMT FROM: Daniel Perley at Liverpool JMU D. A. Perley and C. M. Copperwheat (LJMU) report on behalf of the GROWTH collaboration: We obtained spectroscopy of several of the reported ZTF optical transients (Andreoni et al., GCN 26424) inside the error region of S191213g (LVC, GCN 26402) using the Spectrograph for the Rapid Acquisition of Transients (SPRAT) on the 2m Liverpool Telescope. Observations were conducted on 2019-12-14 between 19:16 and 21:03 (UTC). Spectral classifications were performed with Superfit (Howell et al. 2005). The spectrum of ZTF19acykzsk (AT2019wqj) shows a broad emission feature consistent with H-alpha at the host redshift of z=0.0205.  The overall spectrum is consistent with a Type II supernova close to maximum light. The spectrum of ZTF19acymgzk (AT2019vtj) is an excellent match to a type Ia SN at z~0.05 close to maximum light. The spectrum of ZTF19acykzsp (AT2019wne) has relatively low S/N, but is also a good match to a type Ia SN at maximum light at z~0.16. This is consistent with the photometric SDSS redshift of its probable host galaxy. ZTF19acykwsd (AT2019wnl) was also observed, but no transient was visible at the reported ZTF position in the acquisition exposures (despite good observing conditions) to an upper limit of approximately r > 21.1, well below the reported initial detection magnitude. It may be a short-timescale stellar flare, although no stellar counterpart is visible in the PS1 reference imaging. We conclude that none of these transients are likely to be related to the gravitational-wave event. Further observations of additional sources are ongoing. We acknowledge helpful suggestions from Erik Kool on the GCN draft. DisclaimerNone //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26427 SUBJECT: LIGO/Virgo S191213g: GMOS-N spectroscopy shows ZTF19acykzsk/AT2019wqj is a SN II DATE: 19/12/14 22:02:31 GMT FROM: Tomas Ahumada at U. of Maryland C. Fremling (Caltech), T. Ahumada (UMD), L. P. Singer (NASA), K. De (Caltech), M. M. Kasliwal (Caltech), report on behalf of the ZTF and GROWTH collaborations We obtained spectroscopy of ZTF19acykzsk/AT2019wqj, reported by Andreoni et al. (GCN #26424) with the Gemini Multi-Object Spectrographs (GMOS-N) mounted on the Gemini-North 8-meter telescope on Mauna Kea. We combined six 450 second exposures using the R400+_G5305 grating starting 2019-12-14 11:18 UTC at an airmass of 1.9. A prominent broad H emission feature is seen in the spectrum consistent with a SN II at z=0.02, same redshift of the closest galaxy. Thus, this object is unrelated to LIGO/Virgo S191213g (GCN #26402). We thank the observer S. Xu and the Gemini staff for their rapid response and facilitating this Target of Opportunity observation. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26428 SUBJECT: LIGO/Virgo S191213g: GRAWITA TNG classification of ZTF19acykzsk DATE: 19/12/14 22:11:53 GMT FROM: Nancy Elias-Rosa at ICE-CSIC/IEEC N. Elias-Rosa, S. Benetti (INAF-Padova), S. Piranomonte (INAF-OAR), A. Melandri (INAF-OABr), L. Di Fabrizio (TNG), on behalf of GRAWITA. We report the classification of ZTF19acykzsk (Andreoni et al. GCNC 26424), transient candidate within the error area of the GW event S191213g (LVC, GCNC 26402). We obtained optical spectra covering the range 5000-9400 A with the 3.58m TNG telescope equipped with LRS at Observatorio del Roque de los Muchachos in La Palma (Spain) on Dec 14, 20:13 UT. The spectrum is consistent with those of type II SN few days after explosion, at a z = 0.021, showing a blue continuum and prominent Halpha and HeI 587.6nm lines in emission. Halpha has a FWHM of about 11700km/s. The classification was performed using the GELATO (Harutyunyan et al. 2008, A&A, 488, 383) and SNID (Blondin and Tonry 2007, ApJ, 666, 1024) tools. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26429 SUBJECT: LIGO/Virgo S191213g: WHT spectroscopy of candidate counterparts DATE: 19/12/15 00:07:21 GMT FROM: Morgan Fraser at University College Dublin S. Brennan (University College Dublin), T. Killestein (Warwick), M. Fraser (UCD), P. Jonker (SRON/Radboud University), K. Maguire (TCD), M. Perez Torres (IAC), report on behalf of the GW@WHT collaboration: We obtained an optical spectrum of a number of transients discovered by ZTF (Andreoni et al. GCN 26424) within the localization region of S191213g (LVC, GCN #26402) All spectra were obtained on the night of 2019 Dec 14 using the ACAM instrument mounted on the William Herschel Telescope located on the Roque de Los Muchachos Observatory, La Palma, Spain. AT2019wnn / ZTF19acymcna shows strong Halpha emission at z=0.2, which together with its location in the nucleus of its host galaxy is consistent with an AGN outburst. AT2019wni / ZTF19acymcwv is a Type Ia supernova around +10d from maximum light, at a redshift z=0.09. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26430 SUBJECT: LIGO/Virgo S191213g: Pan-STARRS1 previous detections of ZTF19acykzsk DATE: 19/12/15 00:29:52 GMT FROM: Ken Smith at Queen's University Belfast K. W. Smith, S. J. Smartt, D. R. Young, S. Srivastav, J. Gillanders, O. McBrien, P. Clark, M. Fulton (Queen's University Belfast), M. Huber, K. C. Chambers, H. Flewelling, M. Willman, A. Schultz, E. Magnier, C. Waters, J. Bulger, R. J. Wainscoat (IfA, Hawaii), D. Wright (Univ. of Minnesota) report: Following on from Andreoni et al. (GCN 26424), we report previous Pan-STARRS1 (Chambers et al. 2016) detections of transient ZTF19acykzsk on 2019 December 12. We have 4 detections (PS19heq) at the location of the transient (RA = 02:11:37.08, Dec = +34:02:28.8) as detailed below, all in the PS1 w-band filter. Two of the detections are before the trigger time of S191213g and the other two are from after the event. We therefore do not believe this object is associated with the event. mjd | mag | dmag 58829.3649797 | 19.05 | 0.04 58829.3735363 | 19.00 | 0.05 58830.3920557 | 18.88 | 0.09 58830.3980885 | 18.88 | 0.05 Objects promoted in PS1 are automatically submitted to the TNS. In this case PS19heq was registered as AT2019wqj, but of course, we acknowledge this as a ZTF discovery. The TNS report was also submitted after the GCN 26424 had been sent. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26431 SUBJECT: LIGO/Virgo S191213g: Lulin Follow-up Observations of ZTF19acykzsk/AT2019wqj DATE: 19/12/15 02:17:28 GMT FROM: Albert Kong at NTHU Han-Jie Tan (NCU), Albert Kong (NTHU), Chow-Choong Ngeow (NCU), Wing-Huen Ip (NCU) On behalf of the Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations We report the photometric measurements of the Type II supernova ZTF19acykzsk/AT2019wqj previously associated with the gravitational wave event S191213g (GCN #26402, #26424) using the Lulin One-meter Telescope (LOT) in Taiwan. The observations were conducted using g, r, i filters starting at 2019-12-14 10:13:37 UT and were repeated 7 hours later. Preliminary photometry was obtained by calibrating with the APASS catalog. Its r magnitude is slightly fainter than the observation by Andreoni et al. (GCN #26424) ~14hr earlier and suggests a slow decay. We confirm the report from Andreoni of a red color g-r=0.26. Summary of ZTF19acykzsk/AT2019wqj : UT JD Filter Exp(s) Mag (AB) 2019-12-14 10:16:07 2458831.928 g 300 19.37+/-0.10 2019-12-14 10:21:13 2458831.931 r 300 19.11+/-0.16 2019-12-14 10:26:20 2458831.935 i 300 19.10+/-0.11 2019-12-14 17:21:07 2458832.223 g 300*2 19.51+/-0.11 2019-12-14 17:32:47 2458832.231 r 300*2 19.10+/-0.14 2019-12-14 17:35:24 2458832.233 i 300 19.06+/-0.24 We would like to thank the staff in Lulin Observatory for helping the observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26432 SUBJECT: LIGO/Virgo S191213g: LCOGT photometry of ZTF19acymaru/AT2019wnh DATE: 19/12/15 07:46:53 GMT FROM: Igor Andreoni at Caltech Igor Andreoni (Caltech), Shreya Anand (Caltech), Mansi M. Kasliwal (Caltech), Michael M. Coughlin (Caltech) on behalf of the Global Relay of Observatories Watching Transients Happen (GROWTH) collaboration We used the Sinistro camera on the 1-m LCO Global Telescope Network (LCOGT, Brown et al., 2013) to observe the optical transient ZTF19acymaru/AT2019wnh (GCN #26424). The source was reported via GCN circular during the follow-up of the binary neutron star merger candidate S191213g (LVC, GCN #26402). Images of ZTF19acymaru/AT2019wnh were acquired in g-r-i bands, with an exposure time of 180s for each image. The observations were performed under proposal ID TOM2020A-008, awarded as part of the TOM Community Development Program. The table below reports aperture photometry calibrated against Pan-STARRS DR1 magnitudes (Chambers et al., 2016). The photometry includes host galaxy light, but we expect its contribution to be small. +---------------------------------------------+ | Time (UT) | filter | mag | err | +---------------------+--------+-------+------+ | 2019-12-14 11:14:14 | g | 19.83 | 0.04 | | 2019-12-14 11:17:48 | i | 20.23 | 0.15 | | 2019-12-14 11:24:48 | r | 20.11 | 0.05 | +---------------------+--------+-------+------+ Our LCOGT measurements are consistent with ZTF photometry of ZTF19acymaru/AT2019wnh (GCN #26424) within the uncertainties. The time lag of ~3hr between ZTF and LCOGT observations at >1 day from the merger is too short to exclude any rapid variability. However, we notice that a pre-detection from Pan-STARRS1 exists for this source on 2019-12-04 (TNS report). In light of this, we exclude that ZTF19acymaru/AT2019wnh is associated with S191213g. We thank the TOM Community Development Program and the TOM Toolkit Workshop organizers for the generous LCOGT time allocation. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26433 SUBJECT: LIGO/Virgo S191213g: Upper limits from Insight-HXMT/HE observations DATE: 19/12/15 11:26:56 GMT FROM: Shuo Xiao at IHEP S. Xiao, Y. G. Zheng, C. Cai, Q. Luo, Q. B. Yi, Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, S. L. Xiong, C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team: Insight-HXMT was taking data normally around the reported LIGO/Virgo S191213g event (GCN #26402), trigger time 2019-12-13T04:34:08 UTC. At T0, about 79% of the LIGO localization region was covered by the Insight-HXMT without occultationby the Earth. Within T0 +/- 100 s, no significant excess events (SNR > 3 sigma) are found in a search of the Insight-HXMT/HE raw light curves. Assuming the GW counterpart GRB with three typical GRB Band spectral models, two typical duration timescales (1 s, 10 s) from the center of the LIGO-Virgo location probability map (RA=331.44 deg, DEC=-42.11 deg), the 5-sigma upper-limits fluence (0.2 - 5 MeV, incident energy) are reported below: Band model 1 (alpha=-1.9, beta=-3.7, Ep=70 keV): 1 s: 2.8e-07 erg cm^-2 10 s: 9.0e-06 erg cm^-2 Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV): 1 s: 3.2e-07 erg cm^-2 10 s: 1.1e-06 erg cm^-2 Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV): 1 s: 3.3e-07 erg cm^-2 10 s: 1.4e-06 erg cm^-2 All measurements above are made with the CsI detectors operating in the regular mode with the energy range of about 80-800 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the spacecraft. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26437 SUBJECT: LIGO/Virgo S191213g: Additional candidates from the Zwicky Transient Facility DATE: 19/12/15 18:58:06 GMT FROM: Robert Stein at DESY Robert Stein (DESY), Simeon Reusch (DESY), Dan Perley (LJMU), Igor Andreoni (Caltech) and Michael Coughlin (Caltech) report on behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: We observed the localization region of the S191213g with the Palomar 48-inch telescope, equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). We started observations in the g-band and r-band beginning at 2019-12-13T04:34:15.300 UTC, approximately 0.0 hours after event time. We covered 29.0% of the enclosed probability based on the map in 1922.7 sq deg. This estimate accounts for chip gaps. Each exposure was 30s with a typical depth of 20.5 mag. The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts (Masci et al. 2019). AMPEL (Nordin et al. 2019) was used to search the alerts database for candidates. We reject stellar sources (Tachibana and Miller 2018) and moving objects, apply machine learning algorithms (Mahabal et al. 2019), and remove candidates with history of variability prior to the merger time. We are left with the following 10 high-significance transient candidates, each not previously reported but lying within the 95.0% localization of the skymap. +--------------------------------------------------------------------------------+ | ZTF Name | IAU Name | RA (deg) | DEC (deg) | Filter | Mag | MagErr | +--------------------------------------------------------------------------------+ | ZTF19acykyqu | AT 2019wre | 38.8196462 | +38.319851 | r | 20.86 | 0.19 | | ZTF19acykyrz | AT 2019wrf | 36.0649724 | +38.0803881 | r | 20.61 | 0.17 | | ZTF19acykyzj | AT 2019wrg | 36.0566238 | +51.3671257 | r | 20.62 | 0.16 | | ZTF19acykzfy | AT 2019wrh | 43.1151937 | +41.6603028 | r | 20.96 | 0.18 | | ZTF19acyldum | AT 2019wrn | 79.6818835 | -7.1852786 | g | 19.84 | 0.14 | | ZTF19acyldun | AT 2019wrt | 79.199988 | -7.4787095 | g | 19.97 | 0.17 | | ZTF19acymapa | AT 2019wro | 78.2073207 | -5.9489359 | r | 20.53 | 0.17 | | ZTF19acymaxu | AT 2019wrp | 82.9524848 | -26.6945228 | g | 18.69 | 0.08 | | ZTF19acymixu | AT 2019wrr | 90.9139363 | +60.728245 | r | 20.06 | 0.13 | | ZTF19acymlhi | AT 2019wrs | 91.5924259 | -18.8047267 | g | 19.36 | 0.11 | +--------------------------------------------------------------------------------+ Among our candidates, we highlight two in particular. ZTF19acyldun, first detected 24.0 hours after merger, was not detected 0.9 days prior to a depth of 19.29. The host galaxy spectroscopic redshift of ZTF19acyldun, z = 0.057273, is consistent with the distance estimate for S191213g. ZTF19acymixu, first detected 2.5 hours after merger, was not detected 0.2 days prior to a depth of 18.94. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26467 SUBJECT: LIGO/Virgo S191213g: MASTER OT detection in BNS error-box DATE: 19/12/17 09:03:27 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov,F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov(Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile(Observatorio Astronomico Felix Aguilar OAFA), H.Levato(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias), D. Buckley(South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University) MASTER Global Robotic Net found OT during S191213g (LVC GCN 26402) inspection (Lipunov et al. GCN 26400) MASTER OT J064855.37-055545.7 discovery MASTER-OAFA auto-detection system ( Lipunov et al., "MASTER Global Robotic Net",Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 06h 48m 55.37s -05d 55m 45.7s on 2019-12-16.07539 UT. The OT unfiltered magnitude is 16.0m (mlim=18.7m). The OT is seen in 4 images. There is no minor planet at this place. We have reference image without OT on 2017-10-26.30777 UT with unfiltered magnitude 18.6m. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/064855.37-055545.7.png The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26470 SUBJECT: LIGO/Virgo S191213g: MASTER OT J064855.37-055545.7 is a dwarf nova DATE: 19/12/17 13:29:38 GMT FROM: Denis Denisenko at SAI MSU D. Denisenko (SAI MSU/Education Center Vorobyovy Gory, Moscow) reports: MASTER-OAFA has detected an optical transient in the updated error box of binary NS merger candidate S191213g on 2019-12-16.075 UT (Lipunov et al., GCN 26467) which was also reported to Transient Name Server as AT 2019wwg, see https://wis-tns.weizmann.ac.il/object/2019wwg with the unfiltered magnitudes of 16.6 and 16.3 on 2019-12-16.067 UT and 16.075 UT, respectively. The object is listed in the Pan-STARRS Survey Data Release 1 (Chambers et al., 2016) with the following magnitudes: g=22.12, r=21.64, i=21.47, z=17.68, y=17.44. Checking the PanSTARRS-1 Image Access website at http://ps1images.stsci.edu/cgi-bin/ps1cutouts for the position of MASTER OT J064855.37-055545.7 shows the previous outburst on two images in z and y filters taken on MJD=56597.62894 (2013 Nov. 01) and MJD=56596.63531 (2013 Oct. 31), respectively. The object was at quiescence on all other images, including r-band image on MJD=56622.55184 and i-band image on MJD=56622.57154 (25 days after the outburst). The amplitude of variability (about 5-6 mag) is typical for the outbursts of dwarf novae (cataclysmic variables of U Gem type). Given the galactic latitude b=-2.3 and the density of stars in Monoceros, the detection of the unrelated dwarf nova in the updated S191213g error box covering 10.9 per cent of the entire sky (G. Mo, GCN 26417) is more than likely. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26471 SUBJECT: LIGO/Virgo S191213g: Swift UVOT/XRT observations of three ZTF sources DATE: 19/12/17 13:49:08 GMT FROM: Samantha Oates at MSSL S. R. Oates (Uni. of Birmingham), K. L. Page (U.Leicester), M. De Pasquale (Istanbul U.), A. A. Breeveld (MSSL-UCL), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), P. Brown (TAMU), C. Gronwall (PSU), M. J. Page (UCL-MSSL), M. H. Siegel (PSU), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), S. D. Barthelmy (NASA/GSFC), A. P. Beardmore (U. Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB), S. B. Cenko (NASA/GSFC), G. Cusumano (INAF-IASF PA), V. D’Elia (ASDC), P. A. Evans (U. Leicester), P. Giommi (ASI), D. Hartmann (Clemson U.), J. A. Kennea (PSU), H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC), D. B. Malesani (DTU Space), A. Melandri (INAF-OAB), J. A. Nousek (PSU), P. T. O'Brien (U. Leicester), J. P. Osborne (U. Leicester), C. Pagani (U. Leicester), D.M. Palmer (LANL), M. Perri (ASDC), J. L. Racusin (NASA/GSFC), T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU), G. Tagliaferri (INAF-OAB), A. Tohuvavohu (U Toronto), and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team: We report Swift/UVOT and XRT follow-up observations of 3 objects: ZTF19acykzsk, ZTF19acyldun and ZTF19acymixu reported by Zwicky Transient Facility (Andreoni et al., GCN Circ. 26424; Stein et al., GCN Circ. 26437) found during the search for the EM counterpart of the LVC event S191213g (LIGO/VIRGO Collaboration GCN Circ. 26402). ZTF19acyldun was also detected by UKIRT (Xu et al., GCN Circ. 26450). ZTF19acykzsk was reported to be a SN II using GMOS-N (Fremling et al., GCN Circ. 26427) and GRAWITA TNG (Elias-Rosa et al., GCN Circ. 26428) spectroscopy. Swift/UVOT and XRT observations began 1.6 days after the LIGO/VIRGO trigger (LIGO/VIRGO Collaboration GCN Circ. 26402). For the 3 ZTF objects we give preliminary magnitudes or 3 sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) below: ZTF19acyldun: A point source is detected in the b, u, w1, m2 and w2 filters, but not in the v band. The host galaxy is detected in the v and b filters. The magnitudes have not been host subtracted. Filter T_start(s) T_stop(s) Exp(s) Mag/3sigUL v 237713 238033 315 > 17.9 b 236902 237062 157 18.83 +/- 0.13 u 236737 236897 157 18.18 +/- 0.12 w1 236413 236733 314 17.62 +/- 0.11 m2 238037 238461 416 17.71 +/- 0.13 w2 237068 237708 630 18.19 +/- 0.12 ZTF19acymixu: A weak point source is detected in the b filter only. Filter T_start(s) T_stop(s) Exp(s) Mag/3sigUL v 231843 232162 315 > 19.5 b 231032 231192 157 20.10 +/- 0.37 u 230867 231027 157 > 19.7 w1 230543 230863 315 > 19.7 m2 232167 232532 359 > 19.7 w2 231198 231837 630 > 20.3 ZTF19acykzsk: The host galaxy is detected in all filters. At the location of ZTF19acykzsk (the type II SN) it is not clear if there is a point source, although there may be an enhancement in brightness. We therefore report 3 sigma upper limits: Filter T_start(s) T_stop(s) Exp(s) Mag/3sigUL v 144979 145299 315 > 17.2 b 144169 144329 157 > 17.8 u 144005 144165 157 > 17.5 w1 143680 144000 315 > 17.5 m2 145304 145748 437 > 18.0 w2 144335 144974 630 > 18.1 The magnitudes in the tables are not corrected for the Galactic extinction. None of the three sources was detected by the XRT. In 2 ks of exposure time, the 3-sigma upper limits are as follows: 4.7e-3 count s^-1 (ZTF19acyldun), 5.0e-3 count s^-1 (ZTF19acymixu), 6.5e-3 count/s^-1 (ZTF19acykzsk). This circular is an official product of the Swift team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26477 SUBJECT: LIGO/Virgo S191213g: No candidates found in J-GEM follow-up observations DATE: 19/12/17 17:16:29 GMT FROM: Hiroki Onozato at University of Hyogo Tanaka, M. (Tohoku U.); Nakaoka, T.; Sasada, M.; Akitaya, H. (Hiroshima U.); Yanagisawa, K.; Yoshida, M. (NAOJ); Onozato, H.; Katoh, N.; Takayama, M.; Takahashi, J. (U. Hyogo); Murata, K. L.; Ogawa, F. (Tokyo Tech.); Daikuhara, K.; Tanaka, R. (Toho U.); Ohgami, T. (Konan U.); Itoh, R. (Bisei Astronomical observatory); Utsumi, Y. (Stanford/SLAC) on behalf of J-GEM collaboration We report imaging observations for the gravitational wave event S191213g (Mo et al, GCN Circ. 26402). We started our observations from 2019-12-13 19:57 UT (MJD=58830.83) and ended at 2019-12-15 21:01 UT (MJD=58833.20). We performed galaxy-targeted observations for 57 galaxies (see the table below) selected from the GLADE catalog (Dalya et al. 2018) in the probability skymap of S191213g using the following telescopes and instruments. We found no apparent transient objects in these galaxies to 5 sigma limiting magnitudes in the AB system listed below. galid ra dec dist G R I H J Ks obsid --------------- -------- -------- -------- ---- ---- ---- ---- ---- ---- ------------------------------------------ GL064456-024108 101.2334 -2.6857 125.3799 -- -- -- 15.8 15.3 15.6 Nayuta-NIC GL070356-021440 105.9841 -2.2444 127.5066 14.1 14.0 14.4 19.3 19.2 19.1 MITSuME-Akeno,Nayuta-NIC GL065954-002528 104.9738 -0.4243 64.0723 -- -- -- 19.3 19.4 19.5 OAOWFC,Nayuta-NIC GL070339-021538 105.9108 -2.2606 133.3974 14.1 14.0 14.4 20.2 19.6 20.5 MITSuME-Akeno,Nayuta-NIC GL070527+013843 106.3616 1.6452 101.6106 14.2 14.6 16.3 18.8 18.7 18.7 MITSuME-Okayama,Nayuta-NIC GL070117-071133 105.321 -7.1926 42.9765 -- -- -- 19.6 19.4 20.5 Nayuta-NIC GL065018-025140 102.5737 -2.861 32.2429 -- 17.8 -- 17.4 -- -- Kanata-HONIR GL065354-033741 103.4745 -3.6281 160.6225 15.7 14.9 15.3 19.0 18.8 -- MITSuME-Akeno,Nayuta-NIC GL070332+011707 105.8844 1.2854 78.8108 15.6 14.5 15.3 17.9 18.0 17.6 MITSuME-Akeno,Nayuta-NIC GL070427+003258 106.1121 0.5494 129.2359 15.9 15.8 15.4 18.4 18.1 18.1 MITSuME-Akeno,Nayuta-NIC GL054739-103552 86.9112 -10.5978 176.2266 14.8 15.2 16.2 -- -- -- MITSuME-Okayama GL070424-020546 106.102 -2.0961 115.5631 14.1 14.0 14.4 18.5 17.9 18.0 OAOWFC,MITSuME-Akeno,Nayuta-NIC GL065048-033629 102.701 -3.608 134.8382 14.2 14.5 14.9 -- 16.6 -- OAOWFC,MITSuME-Akeno,MITSuME-Okayama GL065545-022221 103.9366 -2.3726 118.4552 15.7 15.6 15.7 17.7 17.2 17.2 MITSuME-Akeno,Nayuta-NIC GL070256+014001 105.7317 1.6668 206.5006 15.7 15.4 15.8 18.4 -- -- MITSuME-Akeno,Nayuta-NIC GL055137-123354 87.906 -12.5649 100.1857 -- 19.9 -- -- -- -- Kanata-HONIR GL070441-014849 106.1701 -1.8137 106.8234 15.8 15.3 15.7 -- 18.2 -- OAOWFC,MITSuME-Akeno,MITSuME-Okayama GL065246-004356 103.1902 -0.7322 202.594 15.7 15.4 16.1 18.1 17.9 17.7 MITSuME-Akeno,Nayuta-NIC GL070528+021258 106.3674 2.216 127.8873 14.9 15.6 16.9 19.5 19.2 19.4 OAOWFC,MITSuME-Okayama,Nayuta-NIC GL064834+014539 102.14 1.7608 126.8035 14.2 15.2 16.6 19.1 19.0 19.0 MITSuME-Okayama,Nayuta-NIC GL054550-073754 86.4591 -7.6316 96.7483 -- 19.3 -- 18.0 -- -- Kanata-HONIR GL054031-113956 85.1306 -11.6656 105.1381 15.6 15.1 15.6 -- -- -- MITSuME-Akeno GL065050-033643 102.7096 -3.6119 133.5814 14.2 14.5 14.9 -- 16.6 -- OAOWFC,MITSuME-Akeno,MITSuME-Okayama GL055013-100702 87.556 -10.1171 95.3345 14.2 17.3 17.6 14.2 -- -- Kanata-HONIR,MITSuME-Akeno,MITSuME-Okayama GL055007-101040 87.5301 -10.1777 95.2902 17.0 17.3 17.6 14.2 -- -- Kanata-HONIR,MITSuME-Akeno,MITSuME-Okayama GL064601-025210 101.5057 -2.8694 33.4783 -- 16.9 -- 16.3 -- -- Kanata-HONIR GL055012-034512 87.5482 -3.7534 89.1294 16.1 16.5 16.8 -- 17.2 -- OAOWFC,MITSuME-Akeno GL070444+004517 106.1842 0.7546 212.4867 15.9 15.8 15.4 -- -- -- MITSuME-Akeno GL070951-014042 107.462 -1.6783 120.9344 -- 19.1 -- 18.5 -- -- Kanata-HONIR GL065037-035300 102.6533 -3.8832 118.7856 16.1 16.5 12.8 -- 16.6 -- OAOWFC,MITSuME-Akeno,MITSuME-Okayama GL055213-101130 88.0555 -10.1917 99.2893 14.2 19.9 15.7 18.5 -- -- MITSuME-Okayama,Kanata-HONIR GL055300-175234 88.2503 -17.876 46.263 -- 17.0 -- 16.3 -- -- Kanata-HONIR GL070542+002324 106.4269 0.39 103.5782 14.9 19.5 16.0 18.7 -- -- MITSuME-Akeno,Kanata-HONIR GL071033+000916 107.6379 0.1545 168.6599 -- 18.3 -- 17.9 -- -- Kanata-HONIR GL054844-124124 87.1823 -12.69 99.3381 16.1 16.2 17.1 -- -- -- MITSuME-Okayama GL054710-033735 86.7899 -3.6264 166.7677 16.6 16.5 16.7 -- -- -- MITSuME-Akeno GL064135-052241 100.3941 -5.378 64.7166 13.3 13.1 13.2 13.2 -- -- Kanata-HONIR,MITSuME-Okayama GL054801-130903 87.0031 -13.151 190.3952 15.5 16.4 16.8 -- -- -- MITSuME-Akeno GL065032-035004 102.6352 -3.8344 166.4003 16.1 16.5 12.8 -- 16.6 -- OAOWFC,MITSuME-Akeno,MITSuME-Okayama GL054648-115200 86.7017 -11.8666 151.0302 16.4 16.0 16.4 -- -- -- MITSuME-Akeno GL055347-093300 88.4456 -9.5498 194.1131 14.3 14.2 15.9 99.9 -- -- MITSuME-Okayama,Kanata-HONIR GL070455-014548 106.2288 -1.7635 208.9038 15.8 15.3 15.7 -- 18.2 -- OAOWFC,MITSuME-Akeno,MITSuME-Okayama GL055038-100231 87.6584 -10.042 94.9447 14.2 17.3 17.6 -- -- -- MITSuME-Akeno,MITSuME-Okayama GL065618-020809 104.077 -2.1357 193.6556 -- -- 15.7 -- -- -- MITSuME-Akeno GL070952-014416 107.4668 -1.7377 143.0518 -- 19.1 -- 18.5 -- -- Kanata-HONIR GL070254+013958 105.7264 1.666 219.1155 15.7 15.4 15.8 -- -- -- MITSuME-Akeno GL065143-021913 102.9282 -2.3204 174.5572 15.3 15.0 14.9 -- -- -- MITSuME-Akeno GL064922-045337 102.3411 -4.8937 86.7517 16.0 15.3 14.2 -- -- -- MITSuME-Akeno GL062957-042123 97.4871 -4.3564 121.216 16.2 16.4 15.1 -- -- -- MITSuME-Akeno GL064803+001734 102.0135 0.2927 123.8452 13.7 13.2 13.9 -- -- -- MITSuME-Okayama GL061622-212222 94.0921 -21.3727 41.6369 -- 17.1 -- 15.9 -- -- Kanata-HONIR GL063908+022029 99.7852 2.3414 88.6386 -- -- -- 18.9 19.1 18.9 Nayuta-NIC GL064823+003718 102.0938 0.6216 127.8111 -- -- -- 18.5 18.7 18.4 Nayuta-NIC GL070012-001108 105.0502 -0.1854 178.1154 -- -- -- -- 18.0 -- OAOWFC GL065651-004638 104.2109 -0.7773 165.4706 13.7 14.2 15.5 -- -- -- MITSuME-Okayama GL070445+021605 106.1877 2.2679 150.105 14.9 15.6 16.9 -- -- -- MITSuME-Okayama GL070340+011746 105.9172 1.296 170.6441 15.6 14.5 15.3 17.9 18.0 17.6 MITSuME-Akeno,Nayuta-NIC Kanata-HONIR: 150 cm Kanata telescope at Higashi-Hiroshima Observatory and HONIR -- a 2 channel imager (Rc and H or J) (Akitaya et al. 2014, Proc. SPIE 9147, 91474O) MITSuME-Akeno: 50 cm MITSuME telescope at Akeno Observatory and a 3 color imager (g, Rc, Ic) MITSuME-Okayama: 50 cm MITSuME telescope at Okayama Astrophysical Observatory and a 3 color imager (g, Rc, Ic) Nayuta-NIC: 200 cm Nayuta telescope at Nishi-Harima Astronomical Observatory and Nishiharima Infrared Camera, NIC (J, H, Ks) OAOWFC: 91 cm Okayama Astrophysical Observatory NIR Wide Field Camera, OAOWFC (J) (Yanagisawa et al., 2019, PASJ, 71, 118) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26485 SUBJECT: LIGO/Virgo S191213g: Pan-STARRS1 discovery of a potential optical counterpart DATE: 19/12/18 16:02:32 GMT FROM: O. McBrien at QUB O. McBrien, S. J. Smartt, K. W. Smith, D. R. Young, J. Gillanders. S. Srivastav, P. Clark, D. O'Neill, M. Fulton, S. McLaughlin (QUB), K.C. Chambers , M. E. Huber, A.S.B. Schultz, T. de Boer, J. Bulger, J. Fairlamb, C.C. Lin, T. Lowe, E. Magnier , R. J. Wainscoat, M. Willman (IfA, Univ. Hawaii), A. Rest (STScI), C. Stubbs (Harvard), T.-W. Chen (Stockholm) on behalf of the Pan-STARRS collaboration report: We report the Pan-STARRS1 (Chambers et al. 2016, arXiv:1612.05560) discovery of an intrinsically faint optical transient in the 80% probability contour of the compact binary merger event S191213g (The LIGO Scientific Collaboration and the Virgo Collaboration, GCN 26402). The object, PS19hgw, was discovered on MJD 58833.305 (UTC 2019-12-16 07:19:12) at a magnitude of 19.4 +/- 0.1 in the PS1-i band and coordinates RA = 01:55:41.94, Dec = +31:25:04.4. We have registered it on the TNS as AT2019wxt (McLaughlin et al. AstroNote 2019-154). Pan-STARRS1 was observing part of the skymap (LALInference.fits) of S191213g during routine survey operations and its ongoing Pan-STARRS search for kilonovae (Smartt et al. AstroNote 2019-48). We had two more detections on the same night, in the same filter. All exposures were 45 seconds in duration. We have no previous detections at the location of the transient with Pan-STARRS, or indeed with ATLAS either (Tonry et al. 2018, PASP, 130, 4505). There are no previous detections in the public ZTF transient stream (Bellm et al. 2018, PASP, 131, 995) as ingested in Lasair (Smith et al. 2019, RNAAS, 3, 26). We had no detection on the previous night, MJD 58832.305 (UTC 2019-12-15 07:19:12), but only one frame was taken in poor conditions and the limit is not constraining (>19.4 in the PS1-i band). The most recent limits and photometry are: MJD | mag | err | filter 58829.348 | <21.0 | ... | z 58830.379 | <20.3 | ... | z 58830.379 | <20.3 | ... | z 58832.305 | <19.4 | ... | i 58833.335 | 19.37 | 0.07 | i 58833.320 | 19.32 | 0.07 | i 58833.305 | 19.38 | 0.05 | i PS19hgw/AT2019wxt shows an association with the galaxy KUG 0152+311 at a redshift z = 0.036 (144 Mpc, NED). The current luminosity distance estimate accompanying the GW trigger, available through the LALInference.fits.gz skymap (GCN 26417), is 200 +/- 80 Mpc, placing PS19hgw/AT2019wxt within the plausible time-volume for association with this event. The distance modulus to PS19hgw/AT2019wxt is 35.8, giving an absolute magnitude at discovery of -16.5 in the PS1 i-band (assuming foreground extinction of A_i = 0.1). We note that this is 2 magnitudes brighter than AT2017gfo was at +3days after merger, but no less encourage spectroscopic follow-up of this object. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26488 SUBJECT: LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations DATE: 19/12/18 18:31:43 GMT FROM: Dong Xu at NAOC/CAS Z.P. Zhu, B.Y. Yu, D. Xu (NAOC), X. Zhang, S.G. Ma, J.Z. Liu, H.B. Niu (XAO), H.J. Wang, L. Ge, T.M. Zhang, X. Zhou, C.Z. Cui, Y.F. Xu (NAOC), H.B. Zhao, B. Li (PMO), J.R. Mao (YNAO), X. Gao (Urumqi No.1 Senior High School) report on behalf of the GWFUNC collaboration: We observed the high-probability localization region of the LIGO/Virgo gravitational wave trigger S191216ap (GCN #26454) that can be reached by the Nanshan One-meter Wide field Telescope (NOWT) with the FOV of 1.3x1.3 deg^2. Observations started at 11:57:05 UT and ended at 15:19:31 UT on 2019-12-17 in R-band. Typical limiting depth is of ~19.0 mag, and 60 sec for each exposure. Listed below are the center coordinates of each exposure: 21:12:36.864000 +29:36:00.000000 21:18:35.424000 +29:36:00.000000 21:06:33.984000 +30:54:00.000000 21:18:40.608000 +30:54:00.000000 21:06:28.800000 +32:12:00.000000 21:12:36.864000 +32:12:00.000000 21:18:45.792000 +32:12:00.000000 21:12:19.584000 +25:42:00.000000 21:18:05.184000 +25:42:00.000000 21:23:51.648000 +25:42:00.000000 21:12:15.264000 +27:00:00.000000 21:18:05.184000 +27:00:00.000000 21:18:05.184000 +28:18:00.000000 21:23:59.424000 +28:18:00.000000 20:52:44.544000 +37:24:00.000000 21:05:50.784000 +37:24:00.000000 20:52:37.632000 +38:42:00.000000 21:05:57.696000 +38:42:00.000000 20:52:30.720000 +40:00:00.000000 20:59:17.664000 +40:00:00.000000 21:06:04.608000 +40:00:00.000000 21:06:22.752000 +21:48:00.000000 21:17:34.944000 +21:48:00.000000 21:06:18.432000 +23:06:00.000000 21:11:58.848000 +23:06:00.000000 21:06:15.840000 +24:24:00.000000 21:11:58.848000 +24:24:00.000000 21:17:40.992000 +24:24:00.000000 20:43:26.400000 +41:18:00.000000 20:50:21.984000 +41:18:00.000000 20:57:17.568000 +41:18:00.000000 20:43:17.760000 +42:36:00.000000 20:50:21.984000 +42:36:00.000000 20:57:25.344000 +42:36:00.000000 20:43:08.256000 +43:54:00.000000 20:50:21.984000 +43:54:00.000000 20:57:34.848000 +43:54:00.000000 20:47:35.232000 +33:30:00.000000 20:53:50.208000 +33:30:00.000000 21:00:04.320000 +33:30:00.000000 21:00:10.368000 +34:48:00.000000 20:47:24.864000 +36:06:00.000000 20:53:50.208000 +36:06:00.000000 21:00:16.416000 +36:06:00.000000 21:12:18.720000 +14:00:00.000000 21:17:40.992000 +14:00:00.000000 21:23:01.536000 +14:00:00.000000 21:12:16.992000 +15:18:00.000000 21:17:40.992000 +15:18:00.000000 21:23:03.264000 +15:18:00.000000 21:12:14.400000 +16:36:00.000000 21:23:05.856000 +16:36:00.000000 21:12:50.688000 +33:30:00.000000 21:19:04.800000 +33:30:00.000000 21:06:30.528000 +34:48:00.000000 21:12:50.688000 +34:48:00.000000 21:19:09.984000 +34:48:00.000000 21:06:23.616000 +36:06:00.000000 21:12:50.688000 +36:06:00.000000 21:06:28.800000 +17:54:00.000000 21:11:56.256000 +17:54:00.000000 21:17:23.712000 +17:54:00.000000 21:06:25.344000 +19:12:00.000000 21:11:56.256000 +19:12:00.000000 21:06:22.752000 +20:30:00.000000 21:22:59.808000 +17:54:00.000000 21:11:56.256000 +20:30:00.000000 21:28:27.264000 +17:54:00.000000 No credible counterpart candidate was identified in the above fields. In addition, we also imaged the localization region of the HAWC gamma-ray counterpart candidate (GCN #26472) during the searching, which is inside the localization region of the IceCube neutrino counterpart candidate (GCN #26460). Four out of nine GLADE galaxies were covered, as follows: | RAJ2000 | DEJ2000 | Dist | r_SDSS | r_NOWT | | ---------- | --------- | ----- |-------- | ---------- | | 323.482422 | +5.279632 | 274.4 | 16.50 | 16.52 | | 323.056030 | +4.832057 | 219.1 | 15.83 | 15.84 | | 323.173767 | +4.467985 | 292.5 | 16.10 | 16.20 | | 323.034882 | +4.482058 | 340.7 | 16.24 | 16.13 | All NOWT measurements are consistent with the SDSS values. Any significant optical transient within these galaxies can be ruled out. Furthermore, we imaged the HAWC region again, started at 13:09:43.0 UT on 2019-12-18, with 200 s for each exposure in R-band. Our results are as follows: | RAJ2000 | DEJ2000 | Dist | r_SDSS | r_NOWT | | ---------- | --------- | ----- |-------- | ---------- | | 323.482422 | +5.279632 | 274.4 | 16.50 | 16.51 | | 323.056030 | +4.832057 | 219.1 | 15.83 | 15.85 | | 322.921936 | +5.503483 | 232.2 | 15.57 | 15.60 | | 322.838806 | +5.255421 | 179.3 | 15.41 | 15.65 | | 322.821228 | +5.553754 | 338.7 | 15.83 | 15.70 | | 322.749084 | +5.108610 | 330.8 | 15.94 | 15.90 | | 323.173767 | +4.467985 | 292.5 | 16.10 | 16.20 | | 322.906006 | +5.850705 | 323.1 | 16.84 | 16.87 | | 323.034882 | +4.482058 | 340.7 | 16.24 | 16.12 | Again the NOWT measurements are consistent with the SDSS values. Any significant optical transient within these galaxies can be ruled out. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26490 SUBJECT: LIGO/Virgo S191213g: HCT spectroscopy of PS19hgw / AT2019wxt DATE: 19/12/18 21:59:53 GMT FROM: Varun Bhalerao at Indian Inst of Tech A. Dutta (IIAP), B. Kumar (IIAP), H. Kumar (IITB), J. Shejeelammal (IIAP), C. G. Anaswar (IIAP), V. Bhalerao (IITB), G. C. Anupama (IIAP), D. Perley (LJMU) report on behalf of the GROWTH collaboration: We obtained a spectrum of the Pan-STARRS1 candidate counterpart PS19hgw/AT2019wxt (O. McBrien et al., GCN 26485) for the binary neutron star candidate S191213g (GCN 26402) with the HFOSC instrument on the 2m Himalayan Chandra Telescope. We used Grism 7 to obtain a wavelength coverage from approximately 3800 - 7500 angstroms with a resolution of 1200. We took a 3600 second exposure, centred at UT 2019-12-18T18:05:19. The source has a blue, relatively featureless spectrum. Standard galaxy lines are seen at z=0.036, the redshift of the host galaxy. Further observations are encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26491 SUBJECT: LIGO/Virgo S191213g: NOT optical spectroscopy of AT2019wxt (PS19hgw) DATE: 19/12/18 22:17:55 GMT FROM: Daniele B Malesani at DTU Space L. Izzo (DARK/NBI), D. B. Malesani (DTU Space), K. E. Heintz (Univ. Iceland), J. Hjorth (DARK/NBI), B. Milvang-Jensen (DAWN/NBI), S. H. Bruun (DARK/NBI), G. Leloudas (DTU Space), S. Simon-Diaz (IAC; La Laguna), A. de Burgos (NOT; La Laguna), report on behalf of a larger collaboration: We observed the faint transient AT 2019wxt (PS19hgw), spatially and temporally consistent with the gravitational wave event S191213g (LIGO and Virgo collaboration, GCN 26402), with the Nordic Optical Telescope (NOT) equipped with the ALFOSC instrument. A spectrum with 2400 s exposure was secured starting on 2019 Dec 18 at 19:52 UT (MJD 58835.83), covering the wavelength range 3200-9600 AA. Photometry yields i = 18.99 +/- 0.02 mag (AB) calibrated against the Pan-STARRS catalog. Our spectrum reveals a blue, mostly featureless continuum, which can be fit with a flat spectrum (F_nu propto nu^0). A narrow Halpha emission line is detected at z = 0.037, consistent with the catalogued value from NED, which we impute to emission from the underlying host galaxy. Our results are consistent with the findings of Dutta et al. (GCN 26490). At the present stage, the classification of this transient is unclear and we encourage further spectroscopic and photometric follow-up. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26492 SUBJECT: LIGO/Virgo S191213g: AT2019wnh, AT2019wnk and AT2019wrt 10.4m GTC spectroscopy DATE: 19/12/18 22:52:16 GMT FROM: Alberto J. Castro-Tirado at IAA-CSIC A. J. Castro-Tirado, Y.-D. Hu (IAA-CSIC), A. F. Valeev and V. V. Sokolov (SAO-RAS), E. Fernandez-Garcia (IAA-CSIC), I. Carrasco and A. Castellon (UMA), M. D. Caballero-Garcia (ASU-CAS) and S. Geier (GRANTECAN, IAC, ULL), on behalf of a larger collaboration, report: Following the detection of AT2019wnh/ZTF19acymaru, AT2019wnk/ZTF19acylvus and AT2019wrt/ZTF19acyldun (Andreoni et al., GCNC 26424, Stein et al. GCNC 26437) within the error area of the GW event S191213g (LVC, GCNC 26402), we obtained optical spectra covering the range 3700-7400 A with the 10.4m GTC telescope equipped with OSIRIS in La Palma (Spain) starting on Dec 18, 01:02 UT. Details follow: For AT2019wnh/ZTF19acymaru, a magnitude r'= 19.97 +/- 0.02 at 01:02 UT is derived. The GTC spectrum is consistent with a SN Ia at redshift z = 0.167 +/- 0.005. For AT2019wnk/ZTF19acylvus, a magnitude r'= 19.08 +/- 0.02 at 01:22 UT is derived. The GTC spectrum is consistent with a SN Ia at redshift z = 0.1036 +/- 0.005. For AT2019wrt/ZTF19acyldun (also reported by Xu et al. GCNC 26450 and Oates et al. GCNC 26471), a magnitude r'= 18.45 +/- 0.01 at 01:38 UT is derived. It is located in the arm of the host galaxy showing a blue continuum and Balmer emission lines at redshift z = 0.057. Hence we consider it is a LBV in the nearby galaxy. The detection of the object on archival PanStarrs images (one taken in the g-band in Aug 2012) confirms the variability of the transient prior to its current LBV eruption. Therefore we consider that AT2019wnh/ZTF19acymaru, AT2019wnk/ZTF19acylvus and AT2019wrt/ZTF19acyldun are unrelated to the S191213g GW alert. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26493 SUBJECT: LIGO/VIRGO S191213g: LT spectroscopy of AT2019wxt (PS19hgw) DATE: 19/12/18 22:56:37 GMT FROM: Shubham Srivastav at QUB S. Srivastav, S. J. Smartt (QUB) on behalf of a larger collaboration We obtained an optical spectrum of the faint transient AT2019wxt (PS19hgw; GCN 26485, AstroNote 2019-154) with the SPRAT instrument on the Liverpool Telescope. The low S/N spectrum is featureless and shows a blue continuum, similar to the HCT (Dutta et al., GCN 26490) and NOT (Izzo et al., GCN 26491) spectra. Further observations are planned. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26494 SUBJECT: LIGO/VIRGO S191213g: ePESSTO+ spectroscopy of AT2019wxt (PS19hgw) DATE: 19/12/19 03:01:20 GMT FROM: Ting-Wan Chen at MPE T. Müller Bravo (Southampton), T.-W. Chen (Stockholm), M. Fraser (UCD), K. Maguire (TCD), P. Wiseman, M. Pursiainen (Southampton), G. Pignata (UNAB/MAS), I. Arcavi (Tel Aviv University), S. Benetti (INAF-Padova), J. Anderson (ESO), M. Gromadzki (Warsaw), C. Inserra (Cardiff), E. Kankare (Turku), M. Nicholl (Birmingham), O. Yaron (Weizmann), D. Young (QUB), I. Manulis (Weizmann), J. Tonry, L. Denneau, A. Heinze, H. Weiland, H. Flewelling (IfA, Univ. of Hawaii), B. Stalder (LSST), A. Rest (STScI), K. W. Smith, S. J. Smartt, O. McBrien, S. Srivastav (QUB): ePESSTO+, the advanced Public ESO Spectroscopic Survey for Transient Objects (Smartt et al. 2015 2015A&A...579A..40S), reports the followup observations of the counterpart candidate AT2019wxt (=PS19hgw) (McLaughlin et al. AstroNote 2019-154; McBrien et al., GCN 26485) of S191213g (LIGO and Virgo collaboration, GCN 26402). Observations were performed on the ESO New Technology Telescope (NTT) at La Silla on the night of 2019 December 19 00:50 UT (MJD=58836.035), using EFOSC2 and Grism 13 (3985-9315A, 18A resolution) with 1200 sec integration time. In the preliminary reduced spectrum shows blue and featureless continuum, similar to the HCT (Dutta et al., GCN 26490), NOT (Izzo et al., GCN 26491) and LT (Srivastav & Smartt, GCN 26493) spectra. We detect a potential broad feature around 5400 - 6200 Angs (in observed frame). We also detecte a narrow H-alpha emission line at redshift 0.037, which is consistent with the distance of the host galaxy KUG 0152+311 (z = 0.036; Haynes et al. 1997, AJ 113, 1197). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26497 SUBJECT: LIGO/Virgo S191213g: MASTER observation of AT2019wxt (PS19hgw) DATE: 19/12/19 08:55:40 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov,F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov(Lomonosov Moscow State University, SAI, Physics Department), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), R. Podesta, C.Lopez, F. Podesta, C.Francile(Observatorio Astronomico Felix Aguilar OAFA), H.Levato(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias), D. Buckley(South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University) We report the MASTER-Kislovodsk observation of AT2019wxt (PS19hgw) PanSTARR OT optical transient inside 80% probability contour of the compact binary merger event S191213g (The LIGO Scientific Collaboration and the Virgo Collaboration, GCN 26402). MASTER-Kislovodsk auto-detection system detected OT source at (RA, Dec) = 01h 55m 41.97s +31d 25m 03.8s on 2019-12-18.72697 UT. The OT unfiltered magnitude is ~20m (limit 20.2m). The OT is seen in ~18 images. There is no minor planet at this place. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26499 SUBJECT: LIGO/Virgo S191213g: GRAWITA TNG NIR imaging of AT2019wxt (PS19hgw) DATE: 19/12/19 09:35:40 GMT FROM: Paolo D'Avanzo at INAF-OAB P. D'Avanzo, A. Melandri (INAF-OAB), E. Cappellaro, N. Elias-Rosa (INAF-OAPd), M. T. Botticella (INAF-OAC), S. Piranomonte, R. Carini (INAF-OAR), A. Rossi, E. Palazzi (INAF-OAS), E. Brocato (INAF-OAA; INAF-OAR), A. Fiorenzano, D. Carosati (INAF-TNG), report on behalf of GRAWITA: We obtained NIR observations of the faint transient AT2019wxt (PS19hgw; McBrien et al., GCN Circ. 26485), possibly associated with the gravitational wave event S191213g (LVC, GCN Circ. 26402), with the 3.58m TNG telescope equipped with NICS in imaging mode. A series of images were obtained with the J filter on 2019-12-18 from 19:16:04 to 19:59:02 UT (i.e. about 5.6 days after the GW event). The transient is clearly detected with a magnitude J(AB) = 19.6 +/- 0.1 (obtained from preliminary psf photometry calibrated against the 2MASS catalogue and subtracting the host galaxy contribution). [GCN OPS NOTE(19dec19): Per author's request, the Circular reference in the first line was changed from 26845 to 26485.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26500 SUBJECT: LIGO/Virgo S191213g: Palomar 60-inch imaging of AT2019wxt DATE: 19/12/19 10:05:24 GMT FROM: Christoffer Fremling at Caltech C. Fremling (Caltech), M. Kasliwal (Caltech), D. A. Perley (LJMU), and R. Walters (Caltech) report: We observed AT2019wxt (GCN #26485) with the Spectral Energy Distribution Machine (SEDM) on the 60 inch telescope at Palomar Observatory. The SEDM is a low resolution (R ~ 100) integral field unit spectrometer with a multi- band (ugri) rainbow camera imager (see Blagorodnova et al. 2018, PASP, 130, 035003, and Rigault et al. 2019, A&A, 627, A115). The SEDM began observing using the rainbow camera at 2019-12-19 04:25:33.70 UTC. We obtained a series of 180s exposures in ugri filters finding the following magnitudes (AB) after host galaxy subtraction using SDSS images: JD | mag | err | filter 2458836.69 | 19.62 | 0.10 | g 2458836.70 | 19.61 | 0.11 | g 2458836.69 | 19.38 | 0.12 | i 2458836.71 | 19.40 | 0.11 | i 2458836.68 | 19.41 | 0.11 | r 2458836.70 | 19.40 | 0.18 | r 2458836.69 | <17.10 | - | u 2458836.70 | <16.90 | - | u Compared to the photometry reported in GCN #26485, AT2019wxt has stayed at a constant brightness in the the i-band over the last few days (within the reported uncertainties). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26501 SUBJECT: LIGO/Virgo S191213g: Swift UVOT/XRT observations of Pan-STARRS1 candidate: PS19hgw DATE: 19/12/19 11:13:16 GMT FROM: Alice Breeveld at MSSL-UCL S. R. Oates (U. of Birmingham), P. A. Evans (U. Leicester), A. A. Breeveld (MSSL-UCL), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), P. Brown (TAMU), M. De Pasquale (Istanbul U.), C. Gronwall (PSU), M. J. Page (UCL-MSSL), M. H. Siegel (PSU), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), S. D. Barthelmy (NASA/GSFC), A. P. Beardmore (U. Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB), S. B. Cenko (NASA/GSFC), G. Cusumano (INAF-IASF PA), V. D’Elia (ASDC), P. Giommi (ASI), D. Hartmann (Clemson U.), K. L. Page (U.Leicester), J. A. Kennea (PSU), N. J. Klingler (PSU), H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC), D. B. Malesani (DTU Space), A. Melandri (INAF-OAB), J. A. Nousek (PSU), P. T. O'Brien (U. Leicester), J. P. Osborne (U. Leicester), C. Pagani (U. Leicester), D.M. Palmer (LANL), M. Perri (ASDC), J. L. Racusin (NASA/GSFC), T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU), G. Tagliaferri (INAF-OAB), A. Tohuvavohu (U Toronto), and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team: We report Swift/UVOT and XRT follow-up observations of PS19hgw (AT2019wxt; McBrien et al., GCN Circ. 26485) found during the search for the EM counterpart of the LVC event S191213g (LIGO/VIRGO Collaboration GCN Circ. 26402). This object has also been observed by MASTER (Lipunov et al., GCN Circ. 26497), TNG (D'Avanzo et al., GCN Circ. 26499) and SEDM (Fremling et al., GCN Circ. 26500) and spectroscopically by ePESSTO (Müller Bravo et al., GCN Circ. 26494), HCT (Dutta et al., GCN Circ. 26490), NOT (Izzo et al., GCN Circ. 26491) and LT (Srivastav et al., GCN Circ. 26493), indicating this transient is at z = 0.037. Swift/UVOT and XRT observations began 5.7 days after the LIGO/VIRGO trigger (LIGO/VIRGO Collaboration GCN Circ. 26402). Photometry is complicated by the host galaxy, however, in the Swift archive a pre-explosion image is available for the u filter. Comparing the u band images we measure a ~0.8 mag enhancement in flux. For all filters, we have attempted to subtract the host by measuring the host flux at a position offset from PS19hgw, but of a similar brightness as the location of PS19hgw in the pre-explosion image. In the following we give preliminary magnitudes using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373): Filter T_start(s) T_stop(s) Exp(s) Mag v 489252 494253 157 18.53 +\- 0.34 b 488842 493844 157 19.30 +\- 0.32 u 488758 493759 157 18.45 +\- 0.24 w1 488594 493675 315 18.37 +\- 0.23 m2 489336 494468 1163 19.31 +\- 0.32 w2 488928 494169 629 18.82 +\- 0.27 We have checked the reliability of our host subtraction by determining the host subtracted u band magnitude using the host flux measured at the location of PS19hgw in the pre-explosion image. This method results in a u filter magnitude for PS19hgw of 18.49 +\- 0.21, consistent with the u magnitude in the table above. The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.06 in the direction of the burst (Schlegel et al. 1998). In XRT, no source was found at the location of AT2019wxt in 2.6 ks of exposure, starting 5.65 d after the GW trigger. The 3-sigma upper limit is 4.74e-3 ct s^-1. This corresponds to a 0.3-10 keV flux upper limit of 2.04e-13 erg cm^2 s^-1, assuming a power-law spectrum with NH=3e20 cm^-2 and Gamma=1.7. This circular is an official product of the Swift team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26503 SUBJECT: LIGO/Virgo S191213g: Lulin Follow-up Observations of AT2019wxt DATE: 19/12/19 14:44:06 GMT FROM: Albert Kong at NTHU Albert Kong (NTHU), Han-Jie Tan (NCU), Chow-Choong Ngeow (NCU), Wing-Huen Ip (NCU) On behalf of the Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations We report the photometric measurements of AT2019wxt (GCN #26485) associated with the gravitational wave event S191213g (GCN #26402) using the Lulin One-meter Telescope (LOT) in Taiwan. The observations were conducted using g, r, i filters for 300 sec each starting at 2019-12-19 10:42:45 UT. Preliminary photometry (AB) was obtained by calibrating with the PS1 catalogue. We obtained g=19.50+/-0.04, r=19.40+/-0.03, and i=19.47+/-0.06. Compared to the Palomar observations taken 6 hours earlier (GCN #26500), AT2019wxt remains at the same brightness level. We would like to thank the staff in Lulin Observatory for helping the observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26504 SUBJECT: LIGO/Virgo S191213g: VLT spectrum of AT2019wxt (PS19hgw) - a probable Ib supernova DATE: 19/12/19 17:23:41 GMT FROM: Stephen Smartt at Queen's U/Belfast C. Vogl, A. Floers, S. Taubenberger, W. Hillebrandt, S. Suyu (MPA Garching), R. Kotak (Turku), S. J. Smartt, M. Dobson (QUB), B. Leibundgut, J. Spyromilio (ESO), R. Bruch, A. Gal-Yam (Weizmann) The adH0cc programme for an "accurate determination of H0 with core-collapse supernovae" reports the classification of the optical transient AT019wxt (PS19hgw - McLaughlin et al. AstroNote 2019-154 and McBrien et al., GCN 26485). We selected this target as a possible young type II, at the right magnitude in our target redshift range for II-P SNe in the Hubble flow (irrespective of its position in the s191213g sky map; LVC GCN 26402). We generally report our classifications in IAU AstroNotes, where the classification spectra can be found - see Vogel et al. (AstroNote 2019-157) and repeat the information here for the GW follow-up community. Observations were performed on the night of 2019 December 18 with the ESO Very Large Telescope UT1, equipped with the FORS2 spectrograph and grism 300V, covering a wavelength range from 3400 to 9600A at a resolution of 10A. The FORS2 spectrum of SN 2019wxt is dominated by a blue continuum (see also Dutta et al., GCN 26490; Izzo et al., GCN 26491; Srivastav & Smartt, GCN 26493; Muller Bravo et al., GCN 26294 and AstroNote 2019-156), with a few broad undulations and with narrow H II-region lines superimposed. From the narrow emission lines, we derive a redshift of z = 0.036, in agreement with the spectroscopic redshift of the host galaxy. The shallow, broad features can be attributed to helium lines, with the 5876A and 7065A lines of He I providing the cleanest identifications, but plausible identifications of 4471, 4922 and 6678 are visible. The velocity of minima of the absorption troughs appears to be between 7,000- 10,000 km/s. Broad hydrogen lines are not unambiguously detected. Based on these properties, we classify SN 2019wxt as a young supernova of type Ib, but note similarities to some SNe IIb which show a hot blue continuum such as SN 2011fu at comparably early phases. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26508 SUBJECT: LIGO/Virgo S191213g: LBT spectrum of AT2019wxt (PS19hgw) reveals a type IIb supernova DATE: 19/12/20 04:30:21 GMT FROM: Peter Garnavich at U of Notre Dame P. Vallely (OSU), C. M. Wood (ND), C. Phillips (OSU), R. M. Wagner (LBTO and OSU), P. Garnavich (ND), P. Kelly (Minnesota), C. Kochanek (OSU), J. Neustadt (OSU), K. Stanek (OSU), D. Thompson (LBTO), T. Thompson (OSU), C. E. Woodward (Minnesota) We obtained an optical spectrum on 2019 December 19.238 UT of the optical transient AT2019wxt discovered by Pan-STARRS1 (GCN 26485) that might be associated with the BNS merger event S191213g (GCN 26402). The observations were performed using the 2 x 8.4 m Large Binocular Telescope (LBT) and the Multi-Object Double Spectrograph (MODS1 and MODS2; Pogge et al. 2010, SPIE, 7335, 9). The spectra cover the wavelength range 3200 to 9750 Ang at a spectral resolution of about 4 Ang. Our spectrum shows narrow nebular emission line arising from H-alpha, H-beta, [N II] 6548, 6584 Ang; [S II] 6717, 6731 Ang; [O III] 4959, 5007 Ang; and [O II] 3727 Ang superposed on a blue continuum. The wavelengths of the nebular emission lines are consistent with the z = 0.036 redshift of the host galaxy. In addition, broad lines arising from He I 7065 Ang and He I 5875 Ang are present, confirming the detection by Vogl et al. (GCN 26504). The displacement of the weak absorption troughs is difficult to measure but is about -7500 km/s. Our spectrum is in substantial agreement with those described by Vogl et al. (GCN 26504), Dutta et al. (GCN 26490), Izzo et al. (GCN 26491), Srivastav and Smartt (GCN 26493), and Muller Bravo et al. (GCN 26494). Vogl et al. described the spectrum of AT2019wxt as similar to a young type Ib supernova on the basis of the presence of broad He I features but also noted that it was similar to some type IIb supernovae such as SN 2011fu that also show a blue continuum. Our spectrum of AT2019wxt is very similar to the early spectra of SN 2011fu from Kumar et al. (2013, MNRAS, 431, 308, Fig 7). If the spectral evolution of AT2019wxt is similar to 2011fu, the He I lines should strengthen over the next few weeks. Additional optical spectroscopy of AT2019wxt is encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26510 SUBJECT: LIGO/Virgo S191213g: YAHPT Observations of AT2019wxt(PS19hgw) DATE: 19/12/20 08:35:57 GMT FROM: Tianrui Sun at Purple Mountain Obs,CAS Tianrui Sun, Jian Chen, Lei Hu, Fan Li, Ye Yuan, Yanning Fu, Yue Chen, Kelai Meng, Ye Li, Xuefeng Wu (PMO), Wenxiong Li, Xinghan Zhang, Xiaofeng Wang (THU), Lifan Wang (PMO and TAMU) on behalf of a large collaboration. We report the photometric measurements of AT2019wxt (PS19hgw, GCN 26485). The observations were using the YaoAn High Precision Telescope at Yaoan observation station of Purple Mountain Observatory, located in Yunnan Province, China (101.1811° E, 25.528°N). Our observations used the Ic filter for five 180 sec exposures, starting at 14:52:20.540 UTC and ending at 15:07:46.980 UTC on Dec 19 2019. After median combine and image subtraction, the forced photometry (AB) result is Ic=19.59+/-0.07 calibrated with the PS1 catalog. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26517 SUBJECT: LIGO/Virgo S191213g: DCT observation of AT2019wxt DATE: 19/12/20 15:41:24 GMT FROM: Simone Dichiara at UMCP/NASA/GSFC S.Dichiara (UMD, NASA-GSFC), P. Gatkine (UMD), E. Troja (UMD, NASA-GSFC), J.M. Durbak (UMD), S.B. Cenko (NASA-GSFC), A. Kutyrev (UMD, NASA-GSFC), S. Veilleux (UMD), A. D'Ai (INAF-IASFPA), V. La Parola (INAF-IASFPA) report on behalf of a larger collaboration: We observed at the transient AT2019wxt (PS19hgw; McBrien et al., GCN 26485) using the Large Monolithic Imager (LMI) on the 4.3m Lowell's Discovery Channel Telescope (DCT) at Happy Jack, AZ. Observations started on December 20, 02:43:34 UT with SDSS g,r,i,z filters. We detected the source with the following preliminary magnitudes: Start Time Exposure Filter Magnitude (JD) ------------------------------------------------------- 58837.114 3x150 r' 19.43 +- 0.02 58837.120 3x150 i' 19.62 +- 0.01 58837.126 3x150 z' 19.58 +- 0.03 58837.126 3x150 g' 19.86 +- 0.02 ------------------------------------------------------- Magnitudes are in the AB system and are calibrated are calibrated against SDSS catalog. We thank the staff of the Discovery Channel Telescope in particular Casey Kyte, Stephen Levine and Ishara Nisley for assistance with these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26520 SUBJECT: LIGO/Virgo S191213g : SAO 1-m optical observation of AT2019wxt (PS19hgw) DATE: 19/12/20 17:35:51 GMT FROM: Gu Lim at Seoul National U SUBJECT : LIGO/Virgo S191213g : SAO optical observation of AT2019wxt (PS19hgw) Gu Lim (SNU), Myungshin Im (SNU), Gregory S. H. Paek (SNU), Joonho Kim (SNU), Sungyong Hwang (SNU), Bomi Park (SNU), Sophia Kim (SNU), Changsu Choi (SNU), Hyung Mok Lee (KASI), on behalf of a larger collaboration We observed the transient AT2019wxt (PS19hgw; GCN 26485) using Seoul National University Astronomical Observatory (SAO) 1-meter telescope at Seoul, South Korea. The observations began on December 19, 09:12:38 UT with *B, V, R, I* filter taking 180s for each image. After the calibration with PS1 catalog, we conducted image stacking and host galaxy subtraction using PS1 templates. The source is detected in *R, I* images. 5-sigma limit image depth for point source is presented for *B, V* imaging. Start time [MJD] Filter magnitude [AB] ---------------------------------------------------------------------------------- 58836.384 B < 18.730 58836.404 V < 18.833 58836.424 R 19.464+/-0.118 58836.444 I 19.469+/-0.128 Our photometry results are consistent with GCN 26503. *Lim, Gu* Ph. D Course Astronomy Program, Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Korea Center for the Exploration of the Origin of the Universe (CEOU) ᐧ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26521 SUBJECT: LIGO/Virgo S191213g: AT2019wxt 10.4m GTC spectroscopy DATE: 19/12/20 21:30:58 GMT FROM: Eleonora Troja at NASA/GSFC/UMD J. Becerra-Gonzalez (IAC), R. Sanchez-Ramirez (INAF-IAPS), E. Troja (UMD), A. Watson (UNAM), O. Lopez-Cruz (INAOE), and W. H. Lee (UNAM) on behalf of a larger collaboration, report: Following the discovery of AT2019wxt/PS19hgw (McBrien et al., GCN 26485) within the error area of the GW event S191213g (LVC, GCN 26402), we obtained optical spectra with the 10.4m GTC telescope equipped with OSIRIS at La Palma (Spain). Observations were performed under good weather conditions, low airmass, and a seeing ~1 arcsec. They started on December 19 at 21:45 UT, and consisted in 3x300s exposures using both R1000B and R2500I grisms, covering the spectral range of ~3700-10000A. Our spectra show a blue continuum with evident Balmer absorption features, as well as several narrow emission lines at a common redshift of z=0.036, in agreement with previous reports (Dutta et al., GCN 26490; Izzo et al., GCN 26491; Srivastav and Smartt, GCN 26493; Muller Bravo et al., GCN 26494, Vogl et al., GCN 26504; Vallely et al., GCN 26508). The luminosity, color evolution, and spectral features of this transient do not match well with the properties of a kilonova, and instead are consistent with a SNIIb (Vogl et al., GCN 26504; Vallely et al., GCN 26508). Therefore we consider AT2019wxt to be unrelated to the GW event S191213g. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26527 SUBJECT: LIGO/Virgo S191213g: VLA follow-up of AT2019wxt/PS19hg DATE: 19/12/21 09:11:42 GMT FROM: Roberto Ricci at INAF-IRA S. Chastain (GWU), G. Bruni (INAF-IAPS), R. Ricci (INRiM/INAF-IRA), E. Troja (NASA-GSFC/UMCP), A. Van der Horst (GWU), L. Piro (INAF-IAPS) report on behalf of a larger collaboration: We observed the position of the Optical Transient AT2019wxt/PS19hgw (McBrien et al. GCN 26485), with the Karl G. Jansky Very Large Array (VLA) beginning on 2019 Dec 20 00:07 UT in radio band C and K. Analysis is complicated by a nearby bright radio source, coincident with the host galaxy. Based on preliminary analysis, in 1 hour of observations we do not detect any radio emission at the position of the OT to a 3-sigma limit of 174 uJy at 6 GHz (C-band) and 30 uJy at 22 GHz (K-band). We thank Amy Mioduszewski and the rest of the VLA staff for their assistance with rapidly approving and executing these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26558 SUBJECT: LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations DATE: 19/12/22 16:58:41 GMT FROM: Jean-Gregoire Ducoin at LAL J.-G. Ducoin (LAL), D. Turpin (AIM-CEA), S. Antier (APC), B. Chabert (IRAP), D. Corre (LAL), A. Klotz (IRAP), M. Boer (Artemis), N. Christensen (Artemis), M. Coughlin (Caltech), D. Coward (OzGrav-UWA), B. Gendre (OzGrav-UWA), P. Hello (LAL), D. A. Kann (HETH/IAA-CSIC), N. Kochiashvili (Iliauni), C. Lachaud (APC), N. Leroy (LAL), C. Thoene (HETH/IAA-CSIC), D. Turpin (AIM-CEA), X. Wang (THU) report on behalf of the GRANDMA collaboration. We performed galaxy-targeted observations of the LIGO/Virgo event S191213g event (GCN #26402) with the amator astronomers of GRANDMA citizen science program "kilonova-catcher" created by CNRS/IRAP and CNRS/LAL [1]. Denis St-Gelais and Marc Serrau performed galaxy-targeted observations in clear filter of the S191213g event. Denis St-Gelais imaged 12 fields with a 36-cm telescope located in Querétaro (Mexico). Marc Serrau imaged 1 field with a 28-cm telescope located near Haute Provence Observatory (France). The typical magnitude is 19 for both sites with an exposure time of 26 min and 76 min respectively. The target galaxies are selected from the list of potential host galaxies from the Mangrove catalog [2] in the 90% credible area of the localization region of the LIGO/Virgo GW event (LALInference skymap created on 2019-12-14 00:59:57 UTC). No significant transient candidates were found during our analysis [3]. The coverage map is available at: https://grandma-owncloud.lal.in2p3.fr/index.php/s/P3cuh5eZt46lNIs/download The list of the galaxies we observed is given in the table below. TStart and TEnd refers respectively to the time of the first and last exposure for a given galaxy. Observations are not necessarily continuous in this interval. +----------+----------+-----------------------+--------+--------+------+ |TStart | TEnd | Galaxy | RA | DEC | Dist.| |[UTC] | [UTC] | name | [deg] | [deg] | [Mpc]| |----------+----------+-----------------------+--------+--------+------| |2019-12-14|2019-09-03|UGC 02249 |41.849 |45.531 |114.81| | 20:20:35 | 09:41:35 | | | | | |2019-12-15|2019-09-02|UGC 02249 |41.849 |45.531 |114.81| | 01:24:10 | 02:40:10 | | | | | |2019-12-15|2019-09-03|2MASS 03011222+4454285 |45.301 |44.908 |191.45| | 01:54:13 | 02:10:13 | | | | | |2019-12-15|2019-09-03|PGC 090026 |86.831 |-6.836 |95.14 | | 04:36:59 | 04:52:59 | | | | | |2019-12-15|2019-09-03|NGC 2076 |86.698 |-16.782 |33.70 | | 05:05:49 | 05:21:49 | | | | | |2019-12-15|2019-09-03|NGC 2196 |93.040 |-21.806 |36.82 | | 05:33:12 | 05:49:12 | | | | | |2019-12-15|2019-09-03|NGC 2206 |93.999 |-26.765 |85.85 | | 06:00:22 | 06:16:22 | | | | | |2019-12-15|2019-09-03|2MASX 06483359+0145387 |102.140 |1.761 |126.80| | 06:57:12 | 07:11:12 | | | | | |2019-12-15|2019-09-03|2MASX 06443904+0112542 |101.163 |1.215 |42.13 | | 07:21:59 | 07:37:59 | | | | | |2019-12-15|2019-09-03|2MASX 06464860+0041324 |101.703 |0.692 |176.15| | 07:49:39 | 08:05:39 | | | | | |2019-12-15|2019-09-03|2MASX 06404238-0059116 |100.177 |-0.987 |152.74| | 08:28:46 | 08:44:46 | | | | | |2019-12-15|2019-09-03|2MASX 06501768-0251397 |102.574 |-2.861 |32.24 | | 08:59:00 | 09:15:00 | | | | | |2019-12-15|2019-09-03|PGC 983153 |87.658 |-10.042 |94.94 | | 09:26:45 | 09:42:45 | | | | | +----------+----------+-----------------------+--------+--------+------+ GRANDMA (Global Rapid Advanced Network Devoted to the Multi-messenger Addicts) is a network of robotic telescopes connected all over the world with both photometry and spectrometry capabilities for Time-domain Astronomy (https://grandma.lal.in2p3.fr/). Details on the GRANDMA web pages and the citizen science program "kilonova-catcher" are available on https://grandma-kilonovacatcher.lal.in2p3.fr/ [1] https://grandma-kilonovacatcher.lal.in2p3.fr [2] J.-G. Ducoin et al., arXiv:1911.05432 [3] S. Antier et al., MNRAS 2019, https://doi.org/10.1093/mnras/stz3142 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26577 SUBJECT: LIGO/Virgo S191213g: Pan-STARRS monitoring shows PS19hgw (AT2019wxt) to be fading quickly DATE: 19/12/24 17:03:21 GMT FROM: Stephen Smartt at Queen's U/Belfast M. E. Huber, (IfA) S. J. Smartt, O. McBrien, (QUB) K.C. Chambers A.S.B. Schultz (IfA), K. W. Smith, D. R. Young, J. Gillanders. S. Srivastav, P. Clark, D. O'Neill, M. Fulton, S. McLaughlin (QUB), T. de Boer, J. Bulger, J. Fairlamb, C.C. Lin, T. Lowe, E. Magnier , R. J. Wainscoat, M. Willman (IfA, Univ. Hawaii), A. Rest (STScI), C. Stubbs (Harvard), T.-W. Chen (Stockholm) In McBrien et al. (GCN 26485) we reported the Pan-STARRS discovery of the intrinsically faint optical transient PS19hgw (AT2019wxt) in the 80% probability contour of the compact binary merger event S191213g (The LIGO Scientific Collaboration and the Virgo Collaboration, GCN 26402). Spectroscopic follow-up by Izzo et al. (GCN 26491), Srivastav and Smartt (GCN 26493), and Muller Bravo et al. (GCN 26494), Vogl et al. (GCN 26504), Dutta et al. (GCN 26490), Vallely et al. (GCN 26508), and Becerra-Gonzalez et al (GCN 26521) reported a blue continuum with broad shallow He I lines. A spectroscopic classification of a Ib or IIb SN was proposed, and a number of authors proposed it is therefore unrelated to the GW event S191213g. Further observations with Pan-STARRS now show that the transient is fading quite quickly. It faded by 1 mag in g and 0.8 mag in r over 5 days. The SED is clearly cooling, as the fading in the redder bands is less pronounced. g 58836.434471 19.41 0.09 r 58836.436117 19.32 0.07 i 58836.437684 19.30 0.07 z 58836.439253 19.41 0.11 y 58836.441086 19.37 0.22 g 58841.211239 20.43 0.07 r 58841.212850 20.16 0.05 i 58841.214430 19.97 0.04 z 58841.216012 19.82 0.05 y 58841.217616 19.74 0.12 These magnitudes are based on difference imaging with the Pan-STARRS 3Pi survey data (Chambers et al, 2016, arXiv:1612.05560), and hence are reliable and not affected by the host galaxy flux. This is nowhere near as fast a fade as AT2017gfo, which faded by ~4 mags in 5 days in the g-band. And is slower than SN2018kzr, the next fastest fading transient (a possible NS-WD merger, McBrien et al. 2019, ApJ, 885, L23). However it is much faster than the "faint and fast" hydrogen free supernovae like SN2008ha, SN2010ae (Valenti et al. 2009, Nat 459, 674 ; Foley et al. 2009, AJ 138, 376 ; Stritzinger et al. 2014, A&A, 561, 146). Further spectroscopic observations are encouraged to monitor the evolution and determine if this is an unusual, fast fading SN-like transient or if it is related to S191213g. In particular, a spectrum to show if hydrogen has developed or if the He I lines have strengthened is required. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26591 SUBJECT: LIGO/Virgo S191213g: AT2019wxt 10.4m GTC further spectroscopy DATE: 19/12/26 09:37:08 GMT FROM: Alberto J. Castro-Tirado at IAA-CSIC A. F. Valeev (SAO-RAS), A. J. Castro-Tirado, Y.-D. Hu and E. Fernandez-Garcia (IAA-CSIC), V. Sokolov (SAO-RAS), I. Carrasco and A. Castellon (UMA), S. B. Pandey (ARIES) and N. Castro-Rodriguez (GRANTECAN, IAC, ULL), on behalf of a larger collaboration, report: McBrien et al. (GCN 26485) reported the intrinsically faint optical transient PS19hgw (AT2019wxt) in the 80% probability contour of the compact binary merger event S191213g (LVC, GCN 26402) and spectroscopic observations were conducted by Izzo et al. (GCN 26491), Srivastav and Smartt (GCN 26493), Muller Bravo et al. (GCN 26494), Vogl et al. (GCN 26504), Dutta et al. (GCN 26490), Vallely et al. (GCN 26508 ) and Becerra-Gonzalez et al (GCN 26521). We performed a first epoch of spectroscopic observations on Dec 18, 21 UT with the 10.4m GTC telescope (+ OSIRIS) in La Palma (Spain) covering the range 3,700-10,000 A showing a blue continuum with broad shallow He I lines. Following the report by Hubber et al. of a rapid optical decay (GCNC 26577) a second epoch spectrum was obtained on Dec 24, 20 UT with GTC and the same set-up. The 2nd epoch spectrum shows broad features at ~4,500 A and ~5,900A (rest frame) resembling pretty much those of the SN2011fu (a type IIb SN) at about 25 days. Therefore, it seems certain the classification of AT2019wxt as a type IIb SN. See http://jet.sao.ru/~azamat/GW/PS19hgw2019-12-24T19:50.jpeg . This work can be quoted. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26827 SUBJECT: LIGO/Virgo S191213g: Upper limits from Konus-Wind observations DATE: 20/01/20 13:04:45 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, S. Golenetskii, R.Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline, on behalf of the Konus-Wind team, report: Konus-Wind (KW) was observing the whole sky at the time of the LIGO/Virgo event S191213g (2019-12-13 04:34:08.142 UTC, hereafter T0; LIGO/Virgo Collaboration GCN Circ. 26402). No triggered KW GRBs happened ~10.5 days before and ~5 days after T0. The closest waiting-mode GRB 191213A (Cenko et al., GCN 26398; Lien et al., GCN 26418; Ridnaia, et al., GCN Circ. 26484) was observed ~40 minutes before T0 and is spatially inconsistent with the GW event. Using waiting-mode data within the interval T0 +/- 100 s, we found no significant (> 5 sigma) excess over the background in both KW detectors on temporal scales from 2.944 s to 100 s. We estimate an upper limit (90% conf.) on the 20 - 1500 keV fluence to 8.2x10^-7 erg/cm^2 for a burst lasting less than 2.944 s and having a typical KW short GRB spectrum (an exponentially cut off power law with alpha =-0.5 and Ep=500 keV). For a typical long GRB spectrum (the Band function with alpha=-1, beta=-2.5, and Ep=300 keV), the corresponding limiting peak flux is 2.5x10^-7 erg/cm^2/s (20 - 1500 keV, 2.944 s scale). All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27057 SUBJECT: LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations DATE: 20/02/13 13:47:49 GMT FROM: Ulrich Hopp at U Observatory Munich Ulrich Hopp, Matthias Kluge, Claus Goessl, Christoph Ries, Michael Schmidt (University Observatory Munich, LMU, Munich Germany) AT2019wxt = PS19hgw was reported as a potential optical counterpart for the LIGO/Virgo S191213g target at RA = 01:55:41.94, Dec = +31:25:04.4, McBrien et al. 2019 (GCN26485). Follow-up photometry pointed towards a blue and fastly faiding object (Huber et al. 2019, GCN 26577). Follow-up spectroscopy favored the identification as a supernova similar to SN2011fu of type SN IIb (Valeev et al. 2019, GCN 26591 and references therein). We here present three channel optical and near-infrared photometry in g', i' and J taken with the 3KK camera (Lang-Bardl et al., 2016, SPIE 9908) mounted at the 2m telescope of the Wendelstein Observatory (University of Munich). Five epochs were obtained from shortly after detection until about 20 days after maximum. A further image set was taken after the SN faded below our detection limit. That image served for difference image photometry of the SN to minimize the impact of the host galaxy light on the SN photometry. The SN location is within the disk of the spiral host galaxy KUG 0152+311. On our images, the SN appears to be in a inter-arm area of the spiral galaxy. Eigth comparison stars within the detector field served as magnitude reference for our aperture photometry. Magnitudes were obtained through the CDS Strassbourg portal from SDSS DR9 (g', i') and 2MASS (J) catalogs. Errors in the below table include the statistical error of the SN measurement and of the zero-point determination. Date UT g' +/- i' +/- J +/- exp.time sec 2019 12 18 19.78 0.08 20.10 0.09 20.26 0.08 1560 2019 12 19 19.83 0.11 19.84 0.09 19.18 0.11 2340 2019 12 21 20.10 0.06 19.83 0.06 18.96 0.10 1560 2019 12 29 22.77 0.05 20.92 0.06 19.75 0.11 1560 2020 01 06 23.68 0.08 22.64 0.07 20.69 0.12 1560 2020 01 14 <24.0 <22.7 <21.0 Our data around the maximum agree with previously reported optical photometry (e.g. CGN 26485, 26500, 26503, 26517, 26577). Only one NIR observation was reported so far (D'Avanco et al. 2019 GCN 26499). Our data show that the object was very blue in the maximum phase but turned to a much redder color during the decline. The decline was fast with a rate of delta mag/5d 1.12 in g', 0.80 in i', and 0.54 in J, respectively. Our decline rates confirm the early estimate of Huber et al. in g' and i' obtained shortly after maximum. These rates are much faster than the decline of SN2011fu (see Kumar et al. 2013 MNRAS 431, 308). *************************************************************************** * Dr. Ulrich Hopp * *************************************************************************** * Universitaetssternwarte Muenchen * Tel.: + 89 2180 5997 * * Scheiner Str. 1 * Fax.: + 89 2180 6003 * * D 81679 Muenchen * Tel.-MPE: + 89 30000 3913 * * Germany * email: * * und * hopp@usm.uni-muenchen.de * * MPI f. Extraterrestische Physik * hopp@usm.lmu.de * * Postfach 1312 * hopp@mpe.mpg.de * * 85741 Garching * * *************************************************************************** * http://www.usm.lmu.de/people/hopp/hopp.html * ***************************************************************************