//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24997 SUBJECT: LIGO/Virgo S190706ai: Upper limits from IceCube neutrino searches DATE: 19/07/06 23:00:50 GMT FROM: Marcos Santander at U. Alabama/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 S190706ai in a time range of 1000 seconds [3] centered on the alert event time (2019-07-06 22:18:21.345 UTC to 2019-07-06 22:35:01.345 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 S190706ai 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 S190706ai ranges from 0.035 to 0.881 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: 24998 SUBJECT: LIGO/Virgo S190706ai: Identification of a GW compact binary merger candidate DATE: 19/07/06 23:06:25 GMT FROM: Siddharth Mohite at U of Wisconsin-Milwaukee The LIGO Scientific Collaboration and the Virgo Collaboration report: We identified the compact binary merger candidate S190706ai during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2019-07-06 22:26:41.345 UTC (GPS time: 1246487219.345). The candidate was found by the PyCBC Live [1], CWB [2], GstLAL [3], MBTAOnline [4], and SPIIR [5] analysis pipelines. S190706ai is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.9e-09 Hz, or about one in 16 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S190706ai The classification of the GW signal, in order of descending probability, is BBH (99%), Terrestrial (1%), BNS (<1%), NSBH (<1%), or MassGap (<1%). Assuming the candidate is astrophysical in origin, there is strong evidence against the lighter compact object having a mass < 3 solar masses (HasNS: <1%). Using the masses and spins inferred from the signal, there is strong evidence against matter outside the final compact object (HasRemnant: <1%). 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 [6], distributed via GCN notice about 17 minutes after the candidate For the bayestar.fits.gz sky map, the 90% credible region is 1100 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5725 +/- 1446 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] Nitz et al. PRD 98, 024050 (2018) [2] Klimenko et al. PRD 93, 042004 (2016) [3] Messick et al. PRD 95, 042001 (2017) [4] Adams et al. CQG 33, 175012 (2016) [5] Qi Chu, PhD Thesis, The University of Western Australia (2017) [6] Singer & Price PRD 93, 024013 (2016) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25000 SUBJECT: LIGO/Virgo S190706ai Global MASTER-Net observations report DATE: 19/07/06 23:17:13 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 S190706ai errorbox 1152 sec after trigger time at 2019-07-06 22:45:53 UT, with upper limit up to 18.7 mag. The observations began at zenit distance = 107 deg. The sun altitude is -28.9 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=10450 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1242 | 2019-07-06 22:45:53 | MASTER-IAC | ( 12h 3m 31.75s , +55d 17m 03.03s) | P| | 180 | 18.7 | 1242 | 2019-07-06 22:45:53 | MASTER-IAC | ( 12h 2m 12.80s , +55d 21m 21.28s) | P- | 180 | 18.7 | The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25001 SUBJECT: LIGO/Virgo S190706ai: No counterpart candidates in AGILE-MCAL observations DATE: 19/07/07 00:04:04 GMT FROM: Fabrizio Lucarelli at SSDC/INAF-OAR F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, C. Casentini, G. Piano, A. Ursi (INAF/IAPS), F. Verrecchia (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 S190706ai at T0 = 2019-07-06 22:26:41.345 (UT), a preliminary analysis of the AGILE minicalorimeter (MCAL) triggered data found no event candidates within a time interval covering +/- 15 s from the LIGO/Virgo T0. At the T0, about 54% of the S190706ai 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 S190706ai localization region, from a minimum of 1.6E-06 erg cm^-2 to a maximum of 2.2E-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: 25002 SUBJECT: LIGO/Virgo S190706ai: Coverage and upper limits from MAXI/GSC observations DATE: 19/07/07 01:58:09 GMT FROM: Hitoshi Negoro at Nihon U H. Negoro (Nihon U.), N. Kawai, M. Sugizaki (Tokyo Tech), 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 S190706ai at 2019-07-06 22:26:41.344 UTC (GCN 24998). At the trigger time of S190706ai, the high-voltage of MAXI/GSC was off, and it was turned on at T0+730 sec (+12.1 min). The first one-orbit (92 min) scan observation with GSC after the event covered 66% of the 90% credible region of the bayestar skymap from 22:39:0 to 23:58:30 UTC (T0+739 to T0+5509 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: 25004 SUBJECT: LIGO/Virgo S190706ai: No counterpart candidates in HAWC observations DATE: 19/07/07 02:07:22 GMT FROM: Israel Martinez-Castellanos at UMD/HAWC The HAWC Collaboration (https://www.hawc-observatory.org) reports: The HAWC Collaboration performed a follow-up of the gravitational wave trigger S190706ai (GCN #24998). At the time of the trigger the HAWC local zenith was oriented towards (RA, Dec) = (163.7 deg, 19.1 deg). 62% of the GW candidate sky location probability fell within our observable field of view (0-45 deg zenith angle). We performed a search for a short timescale emission using 6 sliding time windows (dt = 0.3s, 1s, 3s, 10s, 30s and 100s), shifted forward in time by 20% of their width. We searched the 95% probability containment area in a timescale-dependent time period, from t0-5dt to t0+10dt, where t0 is the time of the GW trigger. No significant gamma-ray detection above the background was observed. The sensitivity of this analysis is greatly dependent on zenith angle, ranging from 10.8 deg to 45 deg for the area searched in this analysis. The 5sigma detection sensitivity to a 1s (100s) burst in the 80-800GeV energy range goes from 1.6e-6 erg/cm^2 to 1.1e-4 erg/cm^2 (7.5e-6 erg/cm^2 to 5.0e-4 erg/cm^2), depending on the zenith angle. HAWC is a TeV gamma ray water Cherenkov array located in the state of Puebla, Mexico. It is sensitive to the energy range ~0.1-100TeV, and monitors 2/3 of the sky every day with an instantaneous field-of-view of ~2 sr. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25007 SUBJECT: LIGO/Virgo S190706ai: Upper limits from AGILE-GRID observations DATE: 19/07/07 07:22:29 GMT FROM: Fabrizio Lucarelli at SSDC/INAF-OAR F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, C. Casentini, G. Piano, A. Ursi (INAF/IAPS), F. Verrecchia (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 S190706ai at T0 = 2019-07-06 22:26:41.345 (UT) (GCN #24998), we performed an analysis of the AGILE Gamma-Ray Imaging Detector (GRID) data. At the LIGO/Virgo trigger time (T0), the GRID exposure covered nearly 54% of the 90% c.l. localization region (LR), observed at off-axis angles between 30 and 50 deg. An analysis of the data in the energy range 50 MeV - 10 GeV was performed between different time intervals and time integrations near T0. Preliminary values of 3-sigma upper limits (UL) obtained within the accessible LIGO/Virgo 90% c.l. LR are: (T0-2s; T0+2s): from 9.4e-07 to 2.4e-06 erg cm^-2 s^-1; (T0; T0+10s): from 3.4e-07 to 8.9e-07 erg cm^-2 s^-1; (T0; T0+100s): from 3.6e-08 to 2.7e-07 erg cm^-2 s^-1; 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: 25009 SUBJECT: LIGO/Virgo S190706ai: No neutrino counterpart candidates in ANTARES search DATE: 19/07/07 08:04:46 GMT FROM: Antoine Kouchner at ANTARES Collaboration 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 S190706ai event using the 90% contour of the bayestar probability map provided by the GW interferometers (GCN #24998 ). 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/S190706ai.png . Considering the location probability provided by the LIGO/Virgo collaborations, there is a 48.7% 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 2019-07-06 22:26:41 and in the 90% contour of the S190706ai event. The expected number of atmospheric background events in the region visible by ANTARES is 3.63e-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 2.62e-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: 25010 SUBJECT: LIGO/Virgo S190706ai: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observations DATE: 19/07/07 08:39:09 GMT FROM: James Rodi at IAPS-INAF Celia Sanchez-Fernandez (ESA ESAC, Madrid), James Rodi (IAPS-Roma, Italy) V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland) 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 combination of INTEGRAL all-sky detectors (following [1]): SPI/ACS, IBIS/Veto, and IBIS we have performed a search for a prompt gamma-ray counterpart of S190706ai (GCN 24998). At the time of the event (2019-07-06 22:26:41 UTC, hereafter T0), INTEGRAL was operating in nominal mode. The peak of the event localization probability was at an angle of 65 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (19% of optimal) response of ISGRI, somewhat suppressed (40% of optimal) response of IBIS/Veto, and near-optimal (98% of optimal) response of SPI-ACS. The background within +/-300 seconds around the event was very stable (excess variance 1.2). We have performed a search for any impulsive events in INTEGRAL SPI- ACS (as described in [2]), IBIS, and IBIS/Veto data. We do not detect any significant counterparts and estimate a 3-sigma upper limit on the 75-2000 keV fluence of 1.7e-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 ~1.5e-07 (5.4e-08) erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range. For the mean reported distance 5725.0 Mpc this corresponds to the limit on the total isotropic equivalent energy in 1 s of 6.8e+50 erg for the short GRB spectrum and for a long GRB spectrum isotropic equivalent luminosity in 1 s (8 s) of 5.8e+50 erg/s (2.1e+50 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: 25016 SUBJECT: LIGO/Virgo S190706ai: Upper limits from Fermi-GBM Observations DATE: 19/07/07 12:12:45 GMT FROM: Rachel Hamburg at UAH R. Hamburg (UAH) reports on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group: For the LIGO/Virgo detection of GW trigger S190706ai (GCN 24998) and using the initial BAYESTAR skymap, Fermi-GBM was observing 62.0% of the localization probability at event time. There was no Fermi-GBM onboard trigger around the event time of S190706ai. 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 = 170.4 and Dec = -20.2 with a radius of 67.5 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^-7 erg/s/cm^2): Timescale Soft Normal Hard -------------------------------------- 0.1 s: 5.7 7.5 13. 1.0 s: 1.5 2.2 3.9 10. s: 0.5 0.5 0.9 Assuming the median luminosity distance of 5725 Mpc (z=0.881) from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^51 erg/s): Timescale Soft Normal Hard ------------------------------------ 0.1 s: 3.6 4.0 11.7 1.0 s: 1.0 1.2 3.5 10 s: 0.3 0.3 0.8 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25021 SUBJECT: LIGO/Virgo S190706ai: No counterpart candidates in Fermi-LAT observations DATE: 19/07/07 15:47:18 GMT FROM: Elisabetta Bissaldi at INFN,Bari M. Axelsson (KTH and Stockholm Univ.), E. Bissaldi (Politecnico and INFN Bari) and F. Longo (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 6, 2019, for possible high-energy (E > 100 MeV) gamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo trigger S190706ai (GCN 24998). 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 45% of the LIGO probability region at the time of the trigger (T0 = 2019-07-06 22:26:41.345 UTC), and reached full coverage at T0+1 ks. 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 2e-10 and 5e-09 [erg/cm^2/s]. The Fermi-LAT point of contact for this event is Elisabetta Bissaldi (elisabetta.bissaldi@ba.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: 25025 SUBJECT: LIGO/Virgo S190706ai: No counterpart candidates in the Swift/BAT Observations DATE: 19/07/07 21:01:21 GMT FROM: Takanori Sakamoto at AGU S. D. Barthelmy (NASA/GSFC), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), 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 S190706ai (LIGO/VIRGO Collaboration GCN Circ. 24998), where T0 is the LVC trigger time (2019-07-06T22:26:41.344 UTC). The center of the BAT FOV at T0 is RA = 107.468 deg, DEC = -29.539 deg, ROLL = 357.582 deg. The BAT Field of View (>10% partial coding) covers 0.41% of the integrated LVC localization probability, and 1.84% of the galaxy convolved probability (Evans et al. 2016). 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 ~ 7.91 x 10^-8 erg/s/cm^2. Event data are available from T0+29.4 s to T0+32.6 s. No significant detections are found in the 15-350 keV images made using T0+29.4 s and T0+32.6 s. BAT retains decreased, but significant, sensitivity to rate increases for gamma-ray events outside of its FOV. About 68.12% 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/S190706ai/web/source.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25027 SUBJECT: LIGO/Virgo S190706ai: No transient candidates from CALET observations DATE: 19/07/08 03:19:39 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. Ozawa, 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: At the trigger time of the compact binary merger candidate S190706ai, T0 = 2019-07-06 22:26:41.345 UT (The LIGO Scientific Collaboration and Virgo Collaboration, GCN Circ. 24998), the CALET Gamma-ray Burst Monitor (CGBM) high voltages were off (from T0-15 min to T0+12 min). The CALET Calorimeter (CAL) was operating in the high energy trigger mode at the trigger time of S190706ai, but the CAL FOV does not have any overlap with the LVC high probability localization region. The CAL FOV was centered at RA= 210.4 deg, DEC = -45.4 deg at T0. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25028 SUBJECT: LIGO/Virgo S190706ai: No counterpart candidates in KAIT observations DATE: 19/07/08 04:26:29 GMT FROM: Weikang Zheng at UC Berkeley Shaunak Modak, Yukei Murakami, Andrew Hoffman, Thomas de Jaeger, Sergiy Vasylyev, Benjamin Stahl, Keto Zhang, WeiKang Zheng, Nachiket Girish, 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 S190706ai (GCN 24998) 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 129 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 04:22:48, July 7th UT, about 5.9 hours after the trigger, and the last image at 07:18:41 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(July07) RA_J2000 Dec_J2000 ----------------------------------------------- G0777412 04:22:48 12:13:30.498 +61:02:32.7372 G0571516 04:23:57 12:14:48.589 +59:54:21.9384 G0564638 04:25:06 12:16:06.599 +60:35:13.2072 G0904927 04:26:16 12:17:20.5774 +60:52:59.4984 G0787109 04:27:25 12:17:49.7863 +61:29:39.5808 G1199777 04:28:34 12:19:32.0654 +62:09:19.7676 G0732275 04:29:44 12:20:24.5472 +61:05:59.9388 G0698214 04:30:53 12:20:54.5875 +61:59:34.9656 G0565645 04:32:11 12:22:30.8093 +63:54:11.2788 G0682903 04:33:20 12:23:01.0913 +61:42:26.2044 G0765680 04:34:29 12:23:05.2368 +63:13:21.1764 G1908371 04:35:39 12:23:42.9859 +62:56:25.4904 G0790650 04:36:48 12:24:08.4082 +63:38:49.7184 G1709689 04:38:03 12:24:12.24 +58:50:13.308 G0605386 04:39:13 12:24:24.895 +61:50:36.8124 G0656354 04:40:22 12:24:26.2243 +61:31:48.8316 G0634570 04:41:31 12:24:41.8104 +63:23:31.812 G0584909 04:42:41 12:24:42.7039 +61:28:14.8044 G0682297 04:43:50 12:25:19.6802 +61:45:06.7968 G0726198 04:44:59 12:25:43.3375 +62:45:37.7532 G0735369 04:46:09 12:25:44.0587 +61:31:12.7416 G0592302 04:47:18 12:25:53.2325 +62:25:44.652 G0689229 04:48:27 12:27:20.1526 +63:09:45.6264 G0251572 04:49:37 12:28:02.3621 +63:31:13.3752 G0648442 04:50:46 12:29:30.9082 +62:48:36.2376 G0722728 04:51:57 12:30:12.1363 +56:42:07.9812 G0367866 04:53:07 12:31:17.8308 +57:49:48.8172 G0687685 04:54:16 12:31:50.2625 +58:21:28.9296 G0579241 04:55:34 12:31:53.8111 +64:39:09.4824 G0800642 04:56:43 12:31:53.9318 +62:40:16.4964 G0749448 05:06:43 12:32:17.069 +63:57:21.6324 G0801641 05:09:04 12:34:43.7952 +61:24:53.604 G0695406 05:10:13 12:34:51.9103 +58:55:00.21 G0769962 05:11:23 12:34:54.1663 +61:42:25.74 G0505896 05:13:41 12:36:11.4038 +58:04:16.9428 G0606955 05:14:51 12:36:48.977 +62:04:38.4348 G0777685 05:16:00 12:39:54.3677 +61:12:41.4072 G0577774 05:17:09 12:40:07.8295 +62:46:10.4916 G0606869 05:18:18 12:40:34.6764 +62:49:17.382 G0697940 05:19:28 12:41:22.4779 +61:42:42.2856 G0641380 05:21:46 12:42:03.6475 +59:51:16.596 G0818263 05:22:56 12:42:05.4235 +63:06:44.982 G0779598 05:24:05 12:42:23.7158 +60:08:04.8696 G0570567 05:25:15 12:42:39.1003 +61:41:09.4524 G0718455 05:26:24 12:42:54.4519 +63:16:37.5168 G0554983 05:27:35 12:43:00.9559 +56:43:50.5956 G0554755 05:28:46 12:43:05.8154 +63:34:51.4956 G0722161 05:29:56 12:43:19.7827 +58:57:53.6148 G0575799 05:31:05 12:43:51.599 +62:30:25.9416 G0823782 05:32:14 12:45:21.5954 +61:41:39.3756 G0086390 05:33:24 12:47:15.3991 +62:28:53.04 G0783845 05:34:33 12:48:03.0542 +62:36:33.2676 G0623276 05:35:43 12:48:33.7721 +62:27:39.1428 G0810253 05:36:52 12:48:39.9281 +62:37:03.18 G0556824 05:38:01 12:48:40.6054 +59:16:31.71 G0688939 05:39:11 12:49:23.3386 +58:25:15.6612 G0484524 05:40:22 12:50:13.5461 +63:33:58.0752 G0727440 05:47:09 12:52:05.3978 +60:31:45.6888 G0418402 05:48:27 12:52:08.335 +62:53:11.6664 G0790841 05:49:36 12:52:16.0253 +62:40:39.8568 G0695820 05:50:45 12:52:27.7368 +60:04:00.9444 G0551902 05:51:55 12:52:44.5092 +59:15:56.2356 G0797074 05:53:04 12:53:57.9859 +58:17:38.2164 G0562164 05:54:13 12:54:36.1817 +62:13:44.7852 G0741937 05:55:23 12:54:57.4769 +61:27:10.7568 G0644214 05:56:32 12:55:10.6421 +64:15:52.4592 G0752137 05:57:41 12:55:36.7457 +60:10:57.6552 G0792093 05:58:51 12:55:53.1847 +58:19:49.2852 G1463818 06:00:00 12:55:58.3483 +59:06:51.2316 G0644569 06:01:09 12:55:58.7292 +62:08:48.5952 G0763378 06:02:19 12:56:08.0016 +58:45:23.9364 G0501647 06:03:34 12:56:14.3299 +56:52:24.4236 G0764293 06:04:50 12:56:42.0593 +63:05:15.72 G0811967 06:05:59 12:57:12.1471 +63:37:41.5092 G0669049 06:07:08 12:57:57.5026 +62:26:22.4556 G0820710 06:08:18 12:58:20.7715 +61:30:39.33 G0733157 06:09:27 12:59:33.7025 +60:29:04.8624 G0581776 06:10:36 13:01:00.9706 +59:50:56.4504 G0668949 06:11:46 13:01:50.31 +58:19:35.6736 G0811935 06:12:55 13:02:32.6734 +61:28:02.118 G0767619 06:14:04 13:02:39.0307 +62:29:39.084 G0767436 06:15:13 13:02:57.5573 +62:28:51.7764 G0649830 06:16:23 13:04:11.88 +61:11:41.298 G0568950 06:17:32 13:05:01.9226 +60:46:11.0136 G0567935 06:18:41 13:05:22.8626 +61:08:10.0572 G0849452 06:19:51 13:05:32.7758 +60:09:56.0232 G0421347 06:21:00 13:05:47.395 +58:51:08.6472 G0717926 06:28:47 13:06:13.9601 +60:13:02.8452 G1101781 06:29:56 13:06:43.3594 +59:48:47.844 G0570323 06:31:06 13:07:36.9103 +62:12:57.6 G0714491 06:32:15 13:08:07.1484 +60:23:06.2268 G0740340 06:33:24 13:08:24.785 +61:11:30.228 G0814561 06:34:34 13:08:46.5235 +62:16:17.796 G0556963 06:35:43 13:09:14.3153 +62:10:29.9568 G0628708 06:36:52 13:10:04.3286 +60:13:26.8068 G0549578 06:38:02 13:13:13.0555 +60:18:49.7664 G0033113 06:39:11 13:14:52.5257 +60:39:36.8784 G0558654 06:40:20 13:15:10.3747 +60:53:39.9264 G0558303 06:41:30 13:15:12.257 +62:19:34.932 G0714157 06:42:39 13:15:30.7618 +62:07:44.7888 G0709856 06:43:46 13:15:35.0611 +62:07:28.7652 G0615460 06:44:56 13:18:16.8934 +60:26:03.8616 G0798909 06:46:05 13:19:46.9555 +60:38:22.2684 G0827200 06:47:14 13:19:48.1385 +61:37:53.2776 G0825855 06:48:24 13:21:02.1936 +60:52:09.2352 G0566092 06:49:35 13:34:42.5501 +62:34:28.1352 G0698400 06:50:48 14:04:00.2453 +64:40:57.6948 G0561012 06:52:03 14:49:21.6101 +63:16:14.2392 G0776134 06:53:14 15:14:51.3024 +61:39:30.2184 G1089302 06:54:25 15:26:38.2982 +60:56:35.268 G0316711 06:55:36 15:37:36.2074 +63:00:37.8216 G1023955 06:56:46 15:38:32.0287 +61:59:43.494 G0945305 06:57:55 15:44:08.7744 +61:41:54.9636 G0763071 06:59:04 15:46:17.6366 +60:40:21.5796 G1360591 07:00:14 15:47:14.436 +60:47:25.926 G1304744 07:01:23 15:50:53.3167 +61:58:44.0292 G1136264 07:02:32 15:51:01.1976 +60:09:07.092 G1333265 07:05:59 15:52:31.8641 +61:43:45.4152 G1354931 07:07:08 15:53:49.8449 +61:49:45.5628 G1475851 07:08:17 15:55:35.6837 +61:26:18.6108 G1465876 07:09:27 15:56:52.4633 +61:23:46.8096 G1401373 07:10:36 15:57:09.9828 +59:58:29.8164 G1152826 07:11:45 15:59:01.6992 +59:24:21.69 G1165822 07:12:55 15:59:06.8042 +60:32:33 G1179202 07:14:04 16:00:27.0482 +60:20:44.1312 G0872216 07:15:13 16:01:42.2206 +61:52:06.5316 G1420196 07:16:23 16:03:14.945 +61:50:34.4652 G0916525 07:17:32 16:04:50.1636 +59:33:48.9276 G1097215 07:18:41 16:09:06.4855 +60:52:14.1672 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25049 SUBJECT: LIGO/Virgo S190706ai: Updated sky localization DATE: 19/07/10 20:19:20 GMT FROM: Siddharth Mohite at U of Wisconsin-Milwaukee The LIGO Scientific Collaboration and the Virgo Collaboration report: We have conducted further analysis of the LIGO and Virgo data around the time of the compact binary coalescence (CBC) candidate S190706ai (GCN 24998). Parameter estimation has been performed using LALInference [1] and a new sky map, LALInference.offline.fits.gz, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S190706ai LALInference.offline.fits.gz is the preferred sky map at this time. The 90% credible region is 826 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 5263 ± 1402 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: 25052 SUBJECT: LIGO/Virgo S190706ai: Upper limits from Insight-HXMT/HE observations DATE: 19/07/11 00:40:16 GMT FROM: QiBin Yi at IHEP, HXMT Y. G. Zheng, C. Cai, S. Xiao, Q. B. Yi, Q. Luo, 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 S190706ai event (GCN #24998), trigger time 2019-07-06T22:26:41.344 UTC. At T0, about 64% 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=181 deg, DEC=57 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: 3.0e-08 erg cm^-2 10 s: 9.1e-08 erg cm^-2 Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV): 1 s: 5.0e-08 erg cm^-2 10 s: 1.5e-07 erg cm^-2 Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV): 1 s: 2.3e-07 erg cm^-2 10 s: 6.8e-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.