//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25086 SUBJECT: LIGO/Virgo S190718y: Upper limits from IceCube neutrino searches DATE: 19/07/18 15:51:47 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 S190718y in a time range of 1000 seconds [3] centered on the alert event time (2019-07-18 14:26:52.068 UTC to 2019-07-18 14:43:32.068 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 S190718y calculated from the map circulated in the 3-Initial 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 S190718y ranges from 0.029 to 1.150 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] Braun et al., Astroparticle Physics 29, 299 (2008) [3] Baret et al., Astroparticle Physics 35, 1 (2011) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25087 SUBJECT: LIGO/Virgo S190718y: Identification of a GW compact binary merger candidate DATE: 19/07/18 16:07:48 GMT FROM: Varun Bhalerao at Indian Inst of Tech The LIGO Scientific Collaboration and the Virgo Collaboration report: We identified the compact binary merger candidate S190718y during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2019-07-18 14:35:12.068 UTC (GPS time: 1247495730.068). The candidate was found by the GstLAL [1] analysis pipeline. S190718y is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.6e-08 Hz, or about one in 10 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S190718y There were glitches in the interferometers tens of seconds before merger which may affect the sky maps. Further analysis is underway. The classification of the GW signal, in order of descending probability, is Terrestrial (98%), BNS (2%), NSBH (<1%), BBH (<1%), or MassGap (<1%). Assuming the candidate is astrophysical in origin, there is strong evidence for the lighter compact object having a mass < 3 solar masses (HasNS: >99%). Using the masses and spins inferred from the signal, there is strong evidence for matter outside the final compact object (HasRemnant: >99%). One sky map is available at this time and can be retrieved from the GraceDB event page: * bayestar.fits.gz, an updated localization generated by BAYESTAR [2], distributed via GCN notice about 27 minutes after the candidate For the bayestar.fits.gz sky map, the 90% credible region is 7246 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 227 +/- 165 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: 25088 SUBJECT: LIGO/Virgo S190718y Global MASTER-Net observations report DATE: 19/07/18 16:16:57 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-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the LIGO/Virgo S190718y errorbox 1850 sec after trigger time at 2019-07-18 15:06:02 UT, with upper limit up to 18.4 mag. The observations began at zenit distance = 23 deg. The sun altitude is -18.6 deg. The galactic latitude b = -60 deg., longitude l = 98 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/ligo_1.php?id=10491 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1880 | 2019-07-18 15:06:02 | MASTER-Amur | ( 20h 34m 43.42s , +32d 26m 26.69s) | C | 60 | 18.4 | 1968 | 2019-07-18 15:07:30 | MASTER-Amur | ( 20h 30m 10.98s , +32d 38m 06.07s) | C | 60 | 18.4 | 2057 | 2019-07-18 15:08:58 | MASTER-Amur | ( 20h 34m 43.58s , +32d 26m 25.35s) | C | 60 | 18.4 | 2145 | 2019-07-18 15:10:27 | MASTER-Amur | ( 20h 30m 11.11s , +32d 38m 07.77s) | C | 60 | 18.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25091 SUBJECT: LIGO/Virgo S190718y : no neutrino counterpart candidate in ANTARES search DATE: 19/07/18 16:37:37 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 S190718y event using the 90% contour of the bayestar probability map provided by the GW interferometers (GCN#25087). 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/S190718y.png . Considering the location probability provided by the LIGO/Virgo collaborations, there is a 77.5% 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 2019-07-18 14:35:12 and in the 90% contour of the S190718y event. The expected number of atmospheric background events in the region visible by ANTARES is 1.88e-03 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 1.36e-02 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: 25092 SUBJECT: LIGO/Virgo S190718y: No counterpart candidates in INTEGRAL SPI-ACS prompt observation DATE: 19/07/18 16:53:50 GMT FROM: Maeve Doyle at U College Dublin, Ireland Maeve Doyle (UCD, Ireland), 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 S190718y (GCN 25087). At the time of the event (2019-07-18 14:35:12 UTC, hereafter T0), INTEGRAL was operating in nominal mode. The peak of the event localization probability was at an angle of 30 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (19% of optimal) response of ISGRI, strongly suppressed (29% of optimal) response of IBIS/Veto, and somewhat suppressed (55% o f optimal) response of SPI-ACS. The background within +/-300 seconds around the event was rather stable (excess variance 1.2). 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 2.8e-07 erg/cm^2 (within the 50% probability containement 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 ~2.5e-07 (9.4e-08) erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range. For the mean reported distance 227.0 Mpc this corresponds to the limit on the total isotropic equivalent energy in 1 s of 1.7e+48 erg for the short GRB spectrum and for a long GRB spectrum isotropic equivalent luminosity in 1 s (8 s) of 1.5e+48 erg/s (5.8e+47 erg/s) All results quoted are preliminary. This circular is an official product of the INTEGRAL 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: 25095 SUBJECT: LIGO/Virgo S190718y: Upper limits from Fermi-GBM Observations DATE: 19/07/19 00:24:34 GMT FROM: Bagrat Mailyan at UAH B. Mailyan (UAH), R. Hamburg (UAH) and A. Goldstein (USRA) report on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group: For the LIGO/Virgo detection of GW trigger S190718y (GCN 25087) and using the initial BAYESTAR skymap, Fermi-GBM was observing 24.0% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of S190718y. 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. Part of the LVC localization region is behind the Earth for Fermi, located at RA = 15.0 and Dec = 11.4 with a radius of 67.3 degrees. 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^-8 erg/s/cm^2): Timescale soft norm hard -------------------------------------- 0.128 s: 7.2 16. 47. 1.024 s: 3.6 7.2 18. 8.192 s: 1.1 2.0 5.4 Assuming the median luminosity distance of 227 Mpc (z=0.051) from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^47 erg/s): Timescale soft norm hard -------------------------------------- 0.128 s: 6.84 14.2 68.4 1.024 s: 3.42 6.37 26.2 8.192 s: 1.04 1.77 7.86 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25096 SUBJECT: LIGO/Virgo S190718y: No counterpart candidates in the Swift/BAT Observations DATE: 19/07/19 00:27:17 GMT FROM: Amy Lien at GSFC D. M. Palmer (LANL), S. D. Barthelmy (NASA/GSFC), A. Y. Lien (GSFC/UMBC), T. Sakamoto (AGU), A. A. Breeveld (MSSL-UCL), A. P. Beardmore (U. Leicester), 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-SSDC), S. Emery (UCL-MSSL), P. A. Evans (U. Leicester), P. Giommi (ASI), C. Gronwall (PSU), D. Hartmann (Clemson U.), J. A. Kennea (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 (PSU), 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 S190718y (LIGO/VIRGO Collaboration GCN Circ. 25087), where T0 is the LVC trigger time (2019-07-18T14:35:12.067 UTC). The center of the BAT FOV at T0 is RA = 357.719 deg, DEC = -45.287 deg, and the ROLL angle is 94.804 deg. The BAT Field of View (>10% partial coding) covers 6.27% of the integrated LVC localization probability, and 11.94% of the galaxy convolved probability (Evans et al. 2016). Swift/BAT was in SAA during this time. Within T0 +/- 100 s, no significant detections are found in the BAT raw light curves with time bins of 64 ms, 1 s, and 1.6 s. The flux upper limit estimation is unavailable due to the rapid increase of background during the SAA. BAT retains decreased, but significant, sensitivity to rate increases for gamma-ray events outside of its FOV. About 23.33% 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/S190718y/web/source.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25099 SUBJECT: LIGO/Virgo S190718y: Upper limits from CALET observations DATE: 19/07/19 04:01:41 GMT FROM: Yuta Kawakubo at Louisiana State U./CALET V. Pal'shin, A. Yoshida, T. Sakamoto, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: The CALET Gamma-ray Burst Monitor (CGBM) was operating at the trigger time of S190718y T0 = 2019-07-18 14:35:12.068 UT (The LIGO Scientific Collaboration and Virgo Collaboration, GCN Circ. 25087). No CGBM on-board trigger occurred around the event time. Based on the LIGO-Virgo localization sky map, the summed LIGO probabilities inside the CGBM HXM (7-3000 keV) and SGM (40 keV - 28 MeV) fields of view are 9 % and 17 %, respectively (and 22 % credible region of the initial localization map was above the horizon). The HXM and SGM fields of view were centered at RA = 203.3 deg, Dec = -18.0 deg and RA = 195.8 deg, Dec = -11.1 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 low energy trigger mode at the trigger time of S190718y. Using the CAL data, we have searched for gamma-ray events in the 1-10 GeV band from -60 sec to +60 sec from the GW trigger time and found no candidates. The 90% upper limit of CAL is 1.7x10^-6 erg/cm^2/s (1-10 GeV) when the summed LIGO-Virgo probability reaches 5%. The CAL FOV was centered at RA = 195.8 deg, DEC = -11.1 deg at T0. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25100 SUBJECT: LIGO/Virgo S190718y: Coverage and upper limits from MAXI/GSC observations DATE: 19/07/19 05:28:53 GMT FROM: Motoko Serino at RIKEN/MAXI M. Sugizaki, N. Kawai (Tokyo Tech), H. Negoro (Nihon U.), S. Sugita, M. Serino (AGU), M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.), S. Nakahira, T. Mihara, 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. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N. Isobe, 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) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after the LVC trigger S190718y at 2019-07-18 14:35:12.067 UTC (GCN 25087). At the trigger time of S190718y, the high-voltage of MAXI/GSC was on. The instantaneous field of view of GSC at the GW trigger time covered 1% of the 90% credible region of the bayestar sky map, in which we found no significant new X-ray source. The first one-orbit (92 min) scan observation with GSC after the event covered 95% of the 90% credible region of the bayestar skymap from 14:35:12 to 16:07:8 UTC (T0+0 to T0+5516 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: 25102 SUBJECT: LIGO/Virgo S190718y: No counterpart candidates in Fermi-LAT observations DATE: 19/07/19 08:35:27 GMT FROM: Magnus Axelsson at Stockholm U. M. Axelsson (KTH and Stockholm Univ.), E. Bissaldi (Politecnico and INFN Bari), F.Longo (University and INFN, Trieste) and M. Palatiello (University and INFN, Trieste) report on behalf of the Fermi-LAT Collaboration: We have searched data collected by the Fermi Large Area Telescope (LAT) on July 18, 2019, for possible high-energy (E > 100 MeV) gamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo trigger S190718y (GCN 25087). 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 a time, and "cumulative coverage" as the integral of the instantaneous coverage over time. Fermi-LAT had instantaneous coverage of ~30% of the LIGO probability region at the time of the trigger (T0 = 2019-07-18 14:35:12.068 UTC), and reached ~98% coverage at T0+4 ks. The remaining area was not observed within 10 ks of the trigger. We performed a search for a transient counterpart within the observed region of the 90% contour of the LIGO map in a fixed time window from T0 to T0+10 ks. No significant sources were 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 9.8e-11 and 1.1e-07 [erg/cm^2/s]. The Fermi-LAT point of contact for this event is Michele Palatiello (michele.palatiello@gmail.com). 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: 25103 SUBJECT: LIGO/Virgo S190718y: Upper limits from Insight-HXMT/HE observations DATE: 19/07/19 13:31:26 GMT FROM: Qi Luo at IHEP Q. Luo, C. Cai, S. Xiao, Q. B. Yi, Y. G. Zheng, Y. Huang, C. K. Li, X. B. Li, G. 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 S190718y event (GCN #25087), trigger time 2019-07-18T14:35:12.000 UTC. At T0, about 91% of the 90% credible region and all of the 50% credible region of the bayestar sky map were covered by the Insight-HXMT without occultation by 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=305 deg, DEC=32 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: 3.2e-08 erg cm^-2 10 s: 1.5e-07 erg cm^-2 Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV): 1 s: 5.7e-08 erg cm^-2 10 s: 2.8e-07 erg cm^-2 Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV): 1 s: 1.8e-07 erg cm^-2 10 s: 9.4e-07 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. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information could be found at: http://www.hxmt.org. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25105 SUBJECT: MASTER OT detection inside LIGO/Virgo S190718y error box DATE: 19/07/19 15:15:45 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, N.Tyurina , P.Balanutsa, F.Balakin, V.Kornilov, D.Vlasenko, V.Vladimirov, D.Zimnukhov, A.Kuznetsov, I.Gorbunov, A. Chasovnikov, V.Grinshpun, T.Pogrosheva (Lomonosov Moscow State University, SAI, Physics Department), R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias), R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico Felix Aguilar OAFA, San Juan National University), D. Buckley (South African Astronomical Observatory), A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE,SJNU) O. Gress, N.M. Budnev, O.Ershova (Applied Physics Institute, Irkutsk Stat University), V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk Education State University), MASTER OT J203053.79+384020.1 / AT2019lly discovery MASTER-IAC auto-detection system discovered OT source at (RA, Dec) = 20h 30m 53.79s +38d 40m 20.1s on 2019-07-18.92684 UT. The OT unfiltered magnitude is 14.9m (limit 19.4m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2019-07-09.14716 UT with unfiltered magnitude limit 19.7m. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/203053.79384020.1.png There is a DSS source inside 2" with mag = 20.0m. This flash is registered in the error box GW S190718y,but is probably unrelated to the GW event (Cataclysmic Variable) MASTER cover map of Ligo/Virgo S190718y error-field inspection will be available on-line at: https://master.sai.msu.ru/site/master2/ligo_1.php?id=10491 This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25107 SUBJECT: LIGO/Virgo S190718y: Analysis update DATE: 19/07/19 16:31:52 GMT FROM: Varun Bhalerao at Indian Inst of Tech The LIGO Scientific Collaboration and the Virgo Collaboration report: We performed a preliminary follow-up investigation of the compact binary merger candidate S190718y reported in GCN 25087. We removed glitches reported therein, using the PyCBC [1] gating method and reanalyzed the data with PyCBC / Bayestar [2], and also using the same template as the gstlal event. The analysis yields no evidence for retracting this event. There are no updates to the p_astro or significance of this event at this time. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S190718y For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo Public Alerts User Guide . [1] Nitz et al. PRD 98, 024050 (2018) [2] Singer & Price PRD 93, 024013 (2016) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25108 SUBJECT: LIGO/Virgo S190718y: ZTF pre-detection of MASTER candidate AT2019lly DATE: 19/07/19 17:14:50 GMT FROM: Igor Andreoni at Caltech Igor Andreoni (Caltech) reports on behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations We searched for Zwicky Transient Facility (ZTF) detections associated with MASTER OT J203053.79+384020.1 / AT2019lly (Lipunov et al., GCN #25105) in the archive of ZTF alerts. A point source (g=19.85 +- 0.03) is present in the ZTF reference image at the location of AT2019lly and an outburst was detected on 2019-07-15 08:00:18 UT at magnitude g=14.240 +- 0.027. The ZTF detection occurred 3 days before the gravitational wave candidate S190718y (LIGO and Virgo Collaboration, GCN #25087, GCN #25107), excluding an association between MASTER OT J203053.79+384020.1 / AT2019lly and S190718y. Our conclusion is in agreement with the Cataclysmic Variable scenario suggested by Lipunov et al. (GCN #25105). 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; IIT-B, India; IIA, India; LJMU, UK; TTU 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). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25109 SUBJECT: LIGO/Virgo S190718y: No counterpart candidates in KAIT observations DATE: 19/07/19 22:22:54 GMT FROM: Weikang Zheng at UC Berkeley Nachiket Girish, Sergiy Vasylyev, Keto Zhang, WeiKang Zheng, Andrew Hoffman, Benjamin Stahl, and Alexei V. Filippenko (UC Berkeley) report on behalf of the Lick/KAIT GW follow-up team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, observed the 90% region of the gravitational-wavei event S190718y (GCN 25087; GCN 25107) detected by LIGO/Virgo. More than one thousand galaxies were selected from the Glade catalog V1.0 (Dalya et al., 2018, MNRAS, 479, 2374; http://aquarius.elte.hu/glade/) according to their priority score. KAIT observed 209 of them based on their priority scores and elevation visibility, with each clear-filter exposure time being 60 s. The first image was taken at 04:56:24, July 19th UT, about 14.4 hours after the trigger, and the last image at 11:34:24 UT. Our typical limiting mag is 19.0. No viable counterparts were identified and the analysis is ongoing. A full list of galaxies observed by KAIT is given below. GladeID UT(July19) RA_J2000 Dec_J2000 ----------------------------------------------- G0623381 04:56:24 19:20:57.4073 +43:07:57.2052 G0655708 04:57:39 19:36:18.7061 +37:48:07.0164 G1132664 04:58:57 20:11:08.335 +45:15:15.8904 G0172766 05:00:14 20:15:02.6366 +31:40:50.8296 G0419718 05:01:32 20:16:30.2345 +44:21:15.2244 G0673986 05:02:51 20:16:34.5043 +26:58:34.4244 G1298003 05:04:11 20:17:45.769 +45:50:47.634 G0287573 05:05:30 20:19:38.1226 +27:00:10.9368 G0998960 05:06:52 20:19:51.2474 +48:16:20.5572 G1457918 05:08:15 20:20:02.3364 +25:08:48.0444 G1243102 05:09:25 20:21:42.3341 +26:55:00.642 G0289368 05:10:46 20:24:08.1226 +46:28:07.7484 G0002313 05:12:08 20:24:20.2296 +27:03:49.9032 G0418118 05:13:27 20:24:50.8008 +43:02:35.0304 G0639498 05:14:46 20:28:28.8427 +25:43:24.1932 G0563453 05:15:55 20:28:35.0611 +25:44:00.1788 G0041653 05:17:15 20:28:44.9779 +45:41:01.1724 G0721807 05:18:37 20:29:05.9693 +24:42:22.5576 G0428552 05:19:50 20:29:39.463 +32:37:34.4892 G0312245 05:20:59 20:30:29.1065 +33:36:02.8224 G0645883 05:22:11 20:30:29.5531 +27:40:42.906 G0414637 05:23:22 20:30:43.7182 +33:00:07.9092 G1207128 05:24:33 20:37:17.7101 +25:31:37.7652 G1439906 05:25:45 20:38:34.4604 +34:03:23.3172 G0452646 05:26:56 20:38:46.6332 +28:18:13.9572 G1405973 05:28:06 20:39:22.0385 +27:42:40.7952 G1467496 05:29:15 20:39:22.8662 +29:33:27.792 G0217063 05:30:26 20:40:35.5738 +37:40:18.282 G1429059 05:31:37 20:40:46.6478 +30:07:10.6356 G0171171 05:32:49 20:42:15.6372 +37:40:31.4544 G0628332 05:52:51 20:44:09.7999 +33:59:41.5968 G0776012 05:54:03 20:45:56.9458 +28:31:56.0208 G0057545 05:55:14 20:46:38.9942 +36:31:22.7424 G1172157 05:56:23 20:49:25.6788 +33:20:57.714 G1117494 05:57:33 20:53:42.81 +37:56:12.0336 G0142750 05:58:48 20:57:57.7296 +41:06:53.3484 G1069636 05:59:57 21:00:42.2242 +39:53:22.6644 G0862987 06:01:07 21:05:12.3926 +40:46:35.4036 G1444432 06:02:16 21:06:54.9828 +39:55:27.264 G0233317 06:03:25 21:07:28.6963 +40:01:22.026 G1449915 06:04:35 21:08:52.7638 +42:14:50.964 G0175642 06:05:54 21:13:55.752 +51:17:37.68 G0416212 06:07:10 21:14:41.0669 +44:06:32.5836 G1086036 06:08:19 21:14:47.4756 +42:31:12.7308 G1474801 06:09:28 21:16:49.9291 +41:36:48.4164 G1054563 06:10:38 21:18:05.1929 +43:57:30.7512 G0959572 06:11:47 21:18:57.8978 +40:50:12.012 G0778794 06:13:03 21:20:30.066 +37:35:00.2292 G0002434 06:14:14 21:20:42.4805 +44:23:59.0712 G0705251 06:15:23 21:21:39.0454 +44:03:49.9572 G0003499 06:16:35 21:35:32.688 +35:23:54.168 G0636708 06:17:44 21:36:39.353 +35:41:40.8444 G0811558 06:49:28 19:21:10.0488 +43:56:44.3184 G0800990 06:50:37 19:21:31.9044 +43:59:43.4508 G0789501 06:51:47 19:22:31.9922 +44:03:38.5884 G0746609 06:52:56 19:29:59.7144 +43:28:28.8948 G1418181 06:54:18 20:02:49.8852 +49:19:11.2296 G0383988 06:55:29 20:19:01.4722 +44:31:54.642 G0210012 06:56:38 20:21:56.1694 +46:35:14.4024 G0348545 06:57:48 20:23:03.2959 +45:55:17.3208 G0446797 06:59:02 21:09:03.8964 +42:36:11.4624 G0415024 07:00:26 21:11:57.0557 +54:14:51.6228 G1149403 07:01:47 21:13:38.5253 +42:10:46.2972 G1060955 07:02:57 21:17:24.7558 +43:07:26.7312 G0044507 07:04:16 21:18:24.9902 +51:23:57.7104 G1111208 07:05:36 21:18:33.6475 +40:59:52.5696 G1116069 07:06:45 21:19:05.2882 +42:27:31.122 G1367883 07:07:54 21:20:58.5499 +38:03:24.3324 G0305271 07:09:06 21:23:06.7896 +43:29:21.3684 G0540762 07:10:15 21:25:36.1303 +47:42:24.3792 G1394842 07:11:26 21:26:50.0244 +38:12:04.698 G1407104 07:12:36 21:31:30.7764 +38:56:38.1552 G1112914 07:13:47 21:42:08.5913 +33:56:54.2364 G1243714 07:14:56 21:45:18.7279 +34:27:32.22 G0275039 07:16:06 21:49:28.3226 +36:06:06.0228 G0553168 07:18:56 21:53:38.8622 +32:47:28.77 G1460879 07:21:45 21:54:08.7305 +32:54:24.876 G0692325 07:51:02 22:01:07.3901 +16:33:50.1228 G0643019 07:52:24 22:04:40.1441 -16:57:46.3788 G0651982 07:53:46 22:05:40.8912 +16:47:06.72 G0717972 07:54:55 22:09:01.5161 +17:49:17.3136 G0663093 07:56:04 22:09:02.5634 +17:50:19.3164 G0695974 07:57:16 22:11:35.376 +25:51:51.7752 G0798670 07:58:29 22:21:47.6148 +25:19:13.008 G0687421 08:01:18 22:26:54.3677 +19:32:53.6532 G0693516 08:02:28 22:33:50.4785 +20:48:18.9972 G0684178 08:03:37 22:36:28.0298 +21:37:18.6276 G0644132 08:04:53 23:05:27.3706 +21:09:43.272 G0270067 08:06:04 23:18:43.3301 +22:52:26.8752 G0565999 08:07:13 23:20:05.669 +24:13:16.0356 G0657290 08:08:23 23:22:47.5416 +22:56:12.2064 G1269436 08:09:32 23:25:44.8169 +21:04:07.3704 G0873371 08:10:41 23:27:02.6806 +20:15:39.9024 G1089235 08:11:51 23:31:24.8071 +22:48:24.3108 G1453130 08:13:00 23:31:47.5416 +21:31:20.4528 G0635673 08:14:13 23:31:50.2368 +25:32:40.0164 G1460379 08:15:29 23:31:59.2382 +12:58:57.7092 G0507421 08:16:44 23:32:58.1762 +25:57:39.672 G0604275 08:17:54 23:34:05.4785 +22:59:00.0024 G1851005 08:19:03 23:34:49.2 +26:18:39.636 G0801572 08:20:19 23:34:55.2612 +14:17:31.074 G0940627 08:21:30 23:35:13.9452 +22:56:18.8592 G1428518 08:22:40 23:35:35.7934 +20:41:59.5356 G0616925 08:23:49 23:35:39.192 +21:04:39.5544 G0795523 08:24:58 23:36:38.9575 +20:48:06.1992 G0695340 08:26:08 23:36:39.7193 +21:06:07.2036 G1217882 08:47:45 23:36:56.9386 +23:11:07.2348 G0742036 08:49:01 23:37:05.3614 +15:55:58.242 G0717159 08:50:10 23:37:09.3163 +15:55:00.2604 G1458621 08:51:24 23:37:26.316 +09:07:37.1856 G0950103 08:52:39 23:38:00.6151 +20:57:22.05 G0251333 08:53:53 23:38:02.9371 +12:52:12.252 G0771275 08:55:06 23:38:26.9897 +04:48:05.0724 G0614282 08:56:22 23:38:42.2242 +21:30:03.8664 G0772475 08:57:33 23:38:50.603 +27:16:03.9072 G1135364 08:58:45 23:38:55.3418 +22:17:03.8904 G0588368 08:59:54 23:39:19.2408 +21:26:28.1832 G0988727 09:01:01 23:39:21.9653 +20:39:46.1808 G0821402 09:02:13 23:39:27.2167 +14:53:34.8 G0611611 09:03:24 23:39:32.3438 +21:25:59.1744 G1438609 09:04:34 23:39:41.7115 +20:11:58.992 G0744617 09:05:47 23:40:56.521 +14:15:57.5352 G0677365 09:08:12 23:41:08.6134 +24:46:49.4652 G1036668 09:09:21 23:41:13.4179 +22:11:59.028 G0126643 09:10:30 23:41:16.0913 +25:33:04.482 G0000538 09:11:48 23:41:19.4897 +04:01:02.82 G1459451 09:13:04 23:41:21.3574 +20:22:31.044 G1411478 09:14:18 23:41:32.2778 +09:04:31.8504 G1008913 09:15:29 23:41:33.2006 +19:57:11.0304 G0550014 09:16:41 23:41:37.5221 +15:05:06.2772 G0610839 09:17:56 23:41:49.1822 +27:42:09.2232 G1299685 09:19:05 23:41:56.1254 +26:16:02.2584 G1852081 09:20:15 23:41:59.52 +26:48:33.336 G1044821 09:21:24 23:42:03.6401 +27:33:56.412 G1080511 09:22:42 23:42:08.4595 +08:54:03.9456 G0952404 09:34:26 23:42:34.5118 +25:15:00.7776 G1185636 09:35:37 23:42:42.8393 +19:31:38.5392 G0710272 09:36:51 23:42:46.7506 +15:06:53.082 G1078365 09:38:00 23:42:53.2032 +11:46:11.4348 G0105565 09:39:45 23:42:59.2968 +66:09:59.2488 G0480035 09:41:27 23:43:24.4483 +28:30:17.6256 G0785556 09:42:43 23:43:42.019 +17:38:48.444 G0629698 09:43:54 23:43:49.6363 +28:20:21.0768 G0960135 09:45:08 23:44:31.56 +12:42:03.8268 G1108394 09:46:19 23:44:35.4931 +17:56:58.7112 G1894341 09:47:30 23:44:37.2 +27:48:33.264 G1358952 09:48:42 23:44:55.7592 +19:19:27.2568 G1168733 09:49:53 23:45:04.0063 +27:44:10.3092 G0940408 09:51:09 23:45:22.6246 +09:48:22.5612 G1006318 09:52:18 23:45:45.7836 +12:33:35.2728 G1338962 09:53:33 23:46:03.8525 +26:32:00.1212 G0802908 09:54:49 23:46:29.7216 +14:53:11.5584 G0839063 09:55:58 23:46:35.1708 +12:46:25.5612 G1058560 09:57:12 23:46:41.1401 +27:24:08.3196 G1410635 09:58:23 23:46:45.5786 +17:19:05.5704 G0888210 09:59:32 23:47:18.3766 +19:29:38.2056 G0715005 10:00:44 23:47:24.4409 +28:23:36.9132 G0858934 10:01:53 23:47:43.169 +25:33:55.0188 G0630787 10:03:03 23:47:43.1909 +27:25:38.0172 G0471437 10:04:18 23:47:46.2965 +33:26:36.672 G0990722 10:05:29 23:49:01.626 +27:56:58.6104 G0894456 10:06:41 23:49:07.9176 +34:00:26.0784 G0895955 10:07:50 23:49:31.465 +33:35:03.8148 G1437133 10:08:59 23:49:42.0924 +29:05:49.1712 G0685988 10:10:50 23:49:47.0434 +72:38:39.3792 G1080152 10:31:41 23:49:59.0551 +31:07:11.8596 G1308734 10:33:27 23:50:14.3921 +67:57:12.402 G0935229 10:35:19 23:50:18.684 +28:05:21.948 G1085319 10:36:29 23:50:19.2115 +32:33:31.9536 G0714419 10:37:38 23:50:33.9331 +28:59:53.6748 G0585103 10:39:33 23:51:21.4452 +71:31:51.348 G1010191 10:41:28 23:51:26.6676 +30:09:48.51 G0282338 10:42:37 23:51:31.3915 +30:51:19.4868 G1097041 10:43:52 23:51:58.8502 +19:13:49.818 G0149051 10:45:45 23:51:59.5459 +65:53:27.294 G0505505 10:47:35 23:52:09.8731 +31:16:35.6772 G0800525 10:48:45 23:52:26.0083 +33:25:06.006 G0946134 10:50:00 23:52:37.2583 +21:30:54.36 G0368788 10:51:51 23:52:44.0112 +64:53:44.1024 G0678233 10:53:41 23:52:44.773 +33:19:47.4312 G1024148 10:54:56 23:52:51.5844 +18:33:58.3812 G0923373 10:56:10 23:52:59.7655 +33:35:19.5252 G0966996 10:57:23 23:53:02.849 +18:35:50.4708 G0558238 10:58:32 23:53:13.4033 +10:53:41.3124 G0068137 10:59:48 23:53:44.0258 +31:55:51.456 G0797580 11:00:57 23:54:44.1797 +34:20:46.4388 G0347029 11:02:53 23:54:44.3335 +67:47:57.5664 G1329374 11:04:48 23:55:03.0835 +35:48:50.5764 G0133534 11:06:03 23:55:38.8769 +21:49:20.4456 G1422410 11:07:17 23:55:46.6406 +37:13:23.8152 G1215170 11:08:28 23:56:38.1811 +26:34:10.578 G1107920 11:09:37 23:56:50.2001 +19:18:57.4272 G1473772 11:10:51 23:57:00.8935 +33:44:57.5268 G1212312 11:12:02 23:57:03.0103 +25:06:39.4488 G1205490 11:13:11 23:57:17.5416 +26:37:02.5212 G0737131 11:18:18 23:58:03.5815 +16:30:05.1516 G0896765 11:19:27 23:58:05.581 +19:27:57.762 G1053887 11:20:38 23:58:29.3042 +34:11:27.7296 G1120484 11:21:48 23:58:30.0586 +33:56:33.7308 G0959684 11:22:57 23:58:31.7945 +32:22:22.7352 G0992266 11:24:08 23:59:08.1739 +24:51:37.3212 G1324056 11:25:20 23:59:26.9093 +31:23:13.4448 G1247305 11:26:29 23:59:36.0278 +33:28:36.5448 G1031217 11:27:45 23:59:37.6978 +20:06:50.0364 G0425462 11:28:54 23:59:41.4185 +21:13:17.0436 G1454476 11:30:05 23:59:44.3774 +32:22:22.5984 G0060927 11:31:15 23:59:47.1094 +36:58:15.6144 G1189490 11:32:24 23:59:56.7847 +32:54:26.6184 G0211687 11:34:24 23:59:59.4727 +65:09:27.9648 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25117 SUBJECT: LIGO/Virgo S190718y: No counterpart candidates in CNEOST DATE: 19/07/20 05:11:09 GMT FROM: Bin Li at PMO Bin Li, Hai-bin Zhao (PMO),Dong Xu, Zi-pei Zhu, Bang-Yao Yu,Tian-meng Zhang, Xu Zhou,Chen-zhou Cui, Hui-juan Wang(NAOC), Xue-feng Wu, Zhi-ping Jin, Tian-rui Sun, Hao Lu, Ge-tu Zhaori, Ren-quan Hong, Long-fei Hu (PMO), Xiao-feng Wang, Wen-xiong Li (THU),Li-fan Wang (PMO/TAMU), Jin-zhong Liu (XAO), Ji-rong Mao, Jin-ming Bai (YNAO), report on behalf of the CNEOST collaboration. We conducted optical imaging observations for gravitational wave alert with Chinese Near Earth Object Survey Telescope (CNEOST) at Xuyi astronomical station in Jiangsu Province, China (32.75N, 118.47E). The information of observations and preliminary results are listed below. Alert: LIGO/Virgo S190718y (GCN 25087) StartTime (UT): 2019-07-19T12:41:19.523 EndTime (UT): 2019-07-19T18:19:52.108 Skycover (Square Degree): 639.0 Telescope FoV (Square Degree):9.0 #id CentRA(D) CentDEC(D) LimiteMag3_sig 5_sig 10_sig Filter 1 208.869080 -6.786121 20.178 19.181 18.177 SR 2 207.332977 -1.223906 20.265 19.261 18.376 SR 3 210.666458 -4.041420 20.254 19.265 18.329 SR 4 216.043030 -9.596825 20.185 19.217 18.256 SR 5 217.903732 -15.211738 19.997 18.994 17.997 SR 6 215.287582 -12.401288 19.966 19.002 18.058 SR 7 210.364441 -9.628950 20.049 19.056 18.076 SR 8 207.832382 -4.038251 20.262 19.259 18.324 SR 9 210.156891 -1.234565 20.318 19.323 18.407 SR 10 211.684143 -6.830252 20.100 19.149 18.213 SR 11 220.779205 -15.240459 19.922 18.975 18.015 SR 12 208.869080 -6.786121 20.178 19.181 18.177 SR 13 210.156891 -1.234565 20.318 19.323 18.407 SR 14 211.684143 -6.830252 20.100 19.149 18.213 SR 15 216.043030 -9.596825 20.185 19.217 18.256 SR 16 220.779205 -15.240459 19.922 18.975 18.015 SR 17 215.287582 -12.401288 19.966 19.002 18.058 SR 18 306.185486 23.842829 19.291 18.356 17.303 SR 19 305.508270 29.443697 19.330 18.419 17.469 SR 20 307.824493 35.063766 19.557 18.656 17.621 SR 21 312.000488 37.857952 19.497 18.596 17.475 SR 22 314.533600 32.205532 19.391 18.475 17.317 SR 23 308.675293 29.416243 19.335 18.435 17.488 SR 24 305.508270 29.443697 19.330 18.419 17.469 SR 25 307.824493 35.063766 19.557 18.656 17.621 SR 26 312.000488 37.857952 19.497 18.596 17.475 SR 27 314.533600 32.205532 19.391 18.475 17.317 SR 28 307.880554 32.229843 19.462 18.527 17.523 SR 29 307.028320 26.640734 19.367 18.468 17.454 SR 30 304.380890 35.047928 19.489 18.588 17.431 SR 31 309.932098 40.646816 19.639 18.729 17.591 SR 32 311.208282 35.018509 19.474 18.566 17.400 SR 33 314.533600 32.205532 19.391 18.475 17.317 SR 34 307.880554 32.229843 19.462 18.527 17.523 SR 35 308.223480 1.420728 18.660 17.754 16.915 SR 36 309.839081 9.804000 18.793 17.888 16.974 SR 37 312.659424 9.800121 18.743 17.836 16.908 SR 38 309.607025 18.222225 18.980 18.071 17.074 SR 39 306.655151 18.243509 19.021 18.088 17.056 SR 40 312.075226 21.049301 19.014 18.083 17.079 SR 41 318.466370 18.222324 18.949 18.017 16.982 SR 42 313.774658 15.433895 19.007 18.055 17.062 SR 43 322.525757 15.434681 18.984 18.004 16.987 SR 44 315.705475 12.637063 18.935 18.010 17.033 SR 45 321.214417 9.811152 18.731 17.783 16.832 SR 46 316.081055 7.014183 18.795 17.842 16.921 SR 47 311.754395 4.228014 18.686 17.775 16.887 SR 48 313.776703 -1.401701 18.251 17.366 16.533 SR 49 308.223480 1.420728 18.660 17.754 16.915 SR 50 309.839081 9.804000 18.793 17.888 16.974 SR 51 310.891296 15.423524 18.974 18.075 17.106 SR 52 306.073547 21.013973 19.140 18.213 17.172 SR 53 315.045715 21.008123 18.907 17.995 17.038 SR 54 315.521973 18.200771 18.994 18.056 17.059 SR 55 316.691681 15.434895 18.960 18.034 17.055 SR 56 322.525757 15.434681 18.984 18.004 16.987 SR 57 318.607544 12.637962 18.854 17.920 16.948 SR 58 318.352875 9.810987 18.740 17.819 16.888 SR 59 318.875336 7.004980 18.767 17.841 16.919 SR 60 314.550995 4.224255 18.699 17.756 16.866 SR 61 313.830048 1.406936 18.628 17.684 16.804 SR 62 308.185730 -1.344688 18.493 17.572 16.766 SR 63 310.401428 7.007415 18.797 17.879 16.966 SR 64 312.835144 12.623907 18.896 17.977 17.014 SR 65 309.607025 18.222225 18.980 18.071 17.074 SR 66 306.073547 21.013973 19.140 18.213 17.172 SR 67 318.466370 18.222324 18.949 18.017 16.982 SR 68 313.774658 15.433895 19.007 18.055 17.062 SR 69 319.574982 15.416553 18.978 18.053 17.063 SR 70 321.712860 7.031455 18.669 17.751 16.811 SR 71 325.777649 26.589394 15.121 14.167 13.528 SR Detailed data analysis is still in progress and any interesting transients will be reported later. The new resulte will available at http://www.cneost.org/opem/list.php?gdate=2019-07-19 We aslo detect the source — MASTER OT J203053.79+384020.1 / AT2019lly (Lipunov et al., GCN #25105) in our survey, which are labeled OPEM-19vs ( http://www.cneost.org/opem/findname.php?opemname=OPEM-19vs ). And, a point source (r=16.32 +- 0.04 ,observed 2017-11-03) is present in the archive catalog of CNEOST at the location of AT2019lly. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25145 SUBJECT: LIGO/Virgo S190718y: Gaia Photometric Alerts transient candidates DATE: 19/07/24 12:08:47 GMT FROM: Deepak Eappachen at SRON Netherlands Z. Kostrzewa-Rutkowska, D. Eappachen (SRON/RU), S. Hodgkin, A. Delgado, D.L. Harrison, M.van Leeuwen, G. Rixon, A. Yoldas (IoA Cambridge), P.G. Jonker (SRON/RU) on behalf of Gaia Alerts team report the discovery of a transient candidates within the probability skymap of S190718y (LIGO/VIRGO Collaboration GCN 25087): --------------------------------------------------------------------------- Name TNSid Date [TCB] RaDeg DecDeg AlertMag URL ---------------------------------------------------------------------------- Gaia19dbi AT2019lmu 2019-07-19T00:25:08 171.84914 -9.65161 17.52 http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19dbi/ Gaia19dcs AT2019lqm 2019-07-20T21:35:41 347.69159 9.81984. 18.78 http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19dcs/ Gaia19dct AT2019lqn 2019-07-20T12:06:12 348.79552 -33.33181 18.76 http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19dct/ --------------------------------------------------------------------------- Notes: Gaia19dbi - candidate SN near galaxy SDSS J112723.74-093904.1 Gaia19dcs - SN candidate near faint SDSS galaxy Gaia19dct - blue transient 10 arcsec from galaxy 2MASX J23151011-3319533 Acknowledgements: This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. ZKR, DE, and PGJ acknowledge support from the European Research Council under ERC Consolidator Grant agreement no 647208. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25151 SUBJECT: LIGO/Virgo S190718y: Swift XRT observations, 45 X-ray sources DATE: 19/07/25 13:36:34 GMT FROM: Kim Page at U.of Leicester P.A. Evans (U. Leicester), J.A. Kennea (PSU), N.J. Klingler (PSU), A. Tohuvavohu (PSU), S.D. Barthelmy (NASA/GSFC), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), A.A. Breeveld (UCL-MSSL), 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(ASDC), S.W.K. Emery (UCL-MSSL), P. Giommi (ASI), C. Gronwall (PSU), D. Hartmann (U. Clemson), H.A. Krimm (CRESST/GSFC/USRA), N.P.M. Kuin (UCL-MSSL), A.Y. Lien (GSFC/UMBC), F.E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), J.A. Nousek (PSU), S.R. Oates (U. Warwick), P.T. O'Brien (U. Leicester), J.P. Osborne (U. Leicester), C. Pagani (U. Leicester), K.L. Page (U.Leicester), D.M. Palmer (LANL), M. Perri (ASDC), J.L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU), M.H. Siegel (PSU), G. Tagliaferri (INAF-OAB), E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team: Swift has carried out 462 observations of the LVC error region for the GW trigger S190718y convolved with the 2MPZ catalogue (Bilicki et al. 2014, ApJS, 210, 9), using the 'bayestar' GW localisation map. As this is a 3D skymap, galaxy distances were taken into account in selecting which ones to observe. The observations currently span from 13 ks to 365 ks after the LVC trigger, and the XRT has covered 30.9 sq degrees on the sky (corrected for overlaps). This covers 17% of the probability in the 'bayestar' skymap, and 22% after convolving with the 2MPZ galaxy catalogue, as described by Evans et al. (2016, MNRAS, 462, 1591). We have detected 45 X-ray sources. Each source is assigned a rank of 1-4 which describes how likely it is to be related to the GW trigger, with 1 being the most likely and 4 being the least likely. The ranks are described at https://www.swift.ac.uk/ranks.php. We have found: * 0 sources of rank 1 * 0 sources of rank 2 * 27 sources of rank 3 * 18 sources of rank 4 For all flux conversions and comparisons with catalogues and upper limits from other missions, we assumed a power-law spectrum with NH=3x10^20 cm^-2, and photon index (Gamma)=1.7 The results of the XRT automated analysis are online at https://www.swift.ac.uk/LVC/S190718y This circular is an official product of the Swift XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25152 SUBJECT: LIGO/Virgo S190718y: Classification of AT 2019lqn / Gaia19dct as a Type Ia Supernova DATE: 19/07/25 17:14:27 GMT FROM: Iair Arcavi at Tel Aviv University Iair Arcavi (Tel Aviv University), Daichi Hiramatsu (Las Cumbres / UCSB), D. Andrew Howell (Las Cumbres / UCSB), Curtis McCully (Las Cumbres), Jamison Burke (Las Cumbres / UCSB), Craig Pellegrino (Las Cumbres / UCSB), on behalf of the Las Cumbres GW Follow-up Collaboration We obtained an optical spectrum of the transient AT 2019lqn / Gaia19dct (discovered by Gaia within the probability map of S190718y; LIGO/Virgo Collaboration GCN 25087, Kostrzewa-Rutkowska et al. GCN 25145) on 2019 July 24.8 UT with the robotic FLOYDS instrument mounted on the Las Cumbres Observatory 2-meter telescope in Siding Spring, Australia. Using Superfit (Howell et al. 2005, ApJ, 634, 1190) and SNID (Blondin & Tonry 2007, ApJ, 666, 1024) we find good fits to normal Type Ia supernovae at a redshift of z=0.076, and a phase of 9 days after peak. The spectrum is available on the Transient Name Server. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25153 SUBJECT: LIGO/Virgo S190718y: Classification of AT 2019lqm / Gaia19dcs as a Type Ia Supernova DATE: 19/07/26 07:19:57 GMT FROM: Peter Jonker at SRON/RU Kate Maguire (TCD), Mark Magee (TCD), Manuel Torres (IAC), Peter Jonker (SRON/Radboud University), Morgan Fraser (UCD) report on behalf of the GW@WHT collaboration: We obtained an optical spectrum of the transient AT2019lqm / Gaia19dcs (discovered by Gaia within the probability map of S190718y; LIGO/Virgo Collaboration GCN 25087, Kostrzewa-Rutkowska et al. GCN 25145) on 2019 July 25, 04:18 UT using the ACAM instrument mounted on the William Herschel Telescope located on the Roque de Los Muchachos Observatory, La Palma, Spain. The exposure time was 1500 seconds. Using SNID (Blondin & Tonry 2007, ApJ, 666, 1024) we find a good fit to normal Type Ia supernovae at a redshift of z=0.066, about 1 week after peak. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25229 SUBJECT: LIGO/Virgo S190718y: AstroSat CZTI upper limits DATE: 19/07/31 06:50:57 GMT FROM: Varun Bhalerao at Indian Inst of Tech A. Anumarlapudi (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 BBH merger event S190718y (UTC 2019-07-18 14:35:12.000, 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=16: 0:59.8 (240.249), DEC=31: 9:42.8 (31.162)), which is 56.49 deg away from the maximum probability location. At the time of merger event, the Earth-satellite-transient angle corresponding to maximum probability location is ~ 38.26 deg and hence is occulted by Earth in satellite's frame. In a time interval of 100 sec around the event, 57.81 % of sky locations in the 90% probability region for the event is visible in the satellite's frame and the rest of 42.19 % is occulted by earth. CZTI data were de-trended to remove orbit-wise background variation. We then searched data from three of 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 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 convert our count rates into flux by assuming that the source spectrum is a power law with alpha = -1.0. We use a detailed mass model of the satellite to calculate the instrument response for every htm grid point that fall in 90% LIGO localization region and calculate flux limit in that direction. We get the following upper limits for source flux in the 20-200 keV band by taking a probability weighted mean of flux limit and are reported here : 0.1 s: flux limit= 4.71e-06 ergs/cm^2/s 1.0 s: flux limit= 1.48e-05 ergs/cm^2/s 10.0 s: flux limit= 1.72e-05 ergs/cm^2/s 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.