//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21431 SUBJECT: LIGO/Virgo G296853: Identification of a GW Binary Merger Candidate DATE: 17/08/09 10:29:45 GMT FROM: Reed Clasey Essick at MIT The LIGO Scientific Collaboration and the Virgo Collaboration report: The gstlal CBC analysis identified candidate G296853 during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2017-08-09 08:28:21.747 UTC (GPS time: 1186302519.747). Virgo (V1) was observing at the time, but with a range only one quarter of that of L1, and data from V1 was not used when estimating this event’s significance. G296853 is an event of interest because its false alarm rate, as determined by the online analysis, is 7.51e-09 Hz or about one in 4 years, passing our stated alert threshold of ~1/month. The event's properties can be found at this URL: https://gracedb.ligo.org/events/G296853 This event was also identified in real-time by two other pipelines: Coherent WaveBurst (cWB) and Multi-Band Template Analysis (MBTA). A sky map is available at this time and can be retrieved from the GraceDB event page: * bayestar.fits.gz, a localization generated by BAYESTAR, distributed via GCN notice about 40 minutes after the event. At this time, the BAYESTAR map only uses information from H1 and L1. The 50% credible region spans about 316 deg2 and the 90% region about 1155 deg2, and the posterior probability is mostly confined to the Southern Hemisphere. The mean posterior distance is about 1 Gpc. The event appears consistent with the merger of two black holes at this time, and there is little chance either component was a neutron star. Updates on our analysis of this event, including updated localizations which include Virgo data, will be sent as they become available. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21432 SUBJECT: LIGO/Virgo G296853: IceCube neutrino observations DATE: 17/08/09 10:36:33 GMT FROM: Stefan Countryman at LIGO Scientific Collaboration I. Bartos, S. Countryman (Columbia), C. Finley (U Stockholm), E. Blaufuss (U Maryland), R. Corley, Z. Marka, S. Marka (Columbia) on behalf of the IceCube Collaboration We searched IceCube online track-like neutrino candidates (GFU) detected in a [-500,500] second interval about the LIGO-Virgo trigger G296853. We compared the candidate source directions of 4 temporally-coincident neutrinos to the BAYESTAR skymap, with the following parameters: # dt[s] RA[deg] Dec[deg] E[TeV] Sigma[deg] ------------------------------------------------------------------ 1. -310.02 65.9 -5.2 1.11 0.5 2. -128.45 74.0 -29.2 52.68 0.2 3. 361.60 164.0 -14.6 20.50 0.5 4. 438.49 121.1 -64.8 81.83 2.1 (dt--time from GW in [seconds]; RA/Dec--sky location in [degrees]; E--reconstructed secondary muon energy in [TeV]; Sigma--uncertainty of direction reconstruction in [degrees]) The analysis found NO COINCIDENT ONLINE TRACK-LIKE NEUTRINO CANDIDATES detected by IceCube within the 500 second window surrounding G296853 within the BAYESTAR skymap. A coincident neutrino-GW skymap has been posted to GraceDB (< https://gracedb.ligo.org/apiweb/events/G296853/files/ coinc_skymap_initial_icecube.png,0>). A JSON-formatted list of the above neutrinos can be downloaded from GraceDB at: In addition, we are performing coincident searches with other IceCube data streams, including the high-energy starting events (HESE) and Supernova triggers. HESE events have typical energies > 60 TeV and start inside the detector volume, leading to a relatively pure event sample with a high fraction of astrophysical neutrinos. The SN trigger system is sensitive to sudden increases in photomultiplier counts across the detector, which could indicate a burst of MeV neutrinos. We will submit separate GCN circulars if coincident HESE or SN triggers are found. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. For a description of the IceCube realtime alert system, please refer to < http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1610.01814>; for more information on joint neutrino and gravitational wave searches, please refer to . //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21433 SUBJECT: LIGO/Virgo G296853 ANTARES search DATE: 17/08/09 12:25:58 GMT FROM: Damien Dornic at CPPM/CNRS M. Ageron (CPPM/CNRS), B. Baret (APC/CNRS), A. Coleiro (IFIC & APC), D. Dornic (CPPM/CNRS), A. Kouchner (APC/Universite Paris Diderot), 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 G296853 event using the initial LIGO Bayestar probability map at event time. The ANTARES visibility at the time of the alert together with the 90% contour of the probability map are shown in: https://www.cppm.in2p3.fr/~dornic/events/G296853 (gwantares/ GW@ANT29). Considering the location probability provided by the LIGO collaboration, there is a 62% chance that the GW emitter was in the ANTARES field of view. No up-going muon neutrino candidate events were recorded within the 90% contour during a +/- 500s time-window centered on the G296853 event time. The expected number of atmospheric background events in the region visible by ANTARES is ~1.0e-2 in the +/- 500s time window. An extended search during +/- 1 hour gives no up-going neutrino coincidence. An estimate of the upper limit on the associated neutrino fluence will be sent in a subsequent circular. ANTARES, being installed in the Mediterranean Deep Sea, is the largest neutrino detector in the Northern Hemisphere. It is primarily sensitive to astrophysical neutrinos in the TeV-PeV energy range. At 10 TeV, the median angular resolution for muon neutrinos is below 0.5 degrees. In the range 1-100 TeV, ANTARES has the best sensitivity to a large fraction of the Southern sky. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21434 SUBJECT: LIGO/Virgo G296853: AGILE MCAL observations DATE: 17/08/09 13:54:41 GMT FROM: Francesco Verrecchia at ASDC, INAF-OAR A. Ursi, M. Cardillo (INAF/IAPS), F. Verrecchia (SSDC and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), G. Piano (INAF/IAPS), M. Pilia (INAF/OA-Cagliari), C. Pittori (SSDC and INAF/OAR), A. Bulgarelli (INAF/IASF-Bo), G. Minervini, A. Argan, Y. Evangelista (INAF/IAPS), N. Parmiggiani, A. Zoli, V. Fioretti (INAF/IASF-Bo), F. Lucarelli (SSDC and INAF/OAR), I. Donnarumma (ASI), F. Fuschino (INAF/IASF-Bo), M. Marisaldi (INAF/IASF-Bo and Bergen University), A. Giuliani (INAF/IASF-Mi), A. Trois (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 G296853 at T0 = 2017-08-09 08:28:21.747 UTC, a preliminary analysis of the AGILE MiniCALorimeter (MCAL) data found no event candidates within a time interval covering approximately -/+ 10 sec from the LIGO T0. 3-sigma ULs were computed for a 1 s integration time on different celestial positions within the G296853 90% localization region, taking into consideration the nearest triggered data acquisition (about 14 sec after the LIGO T0), resulting in typical values of the fluence UL ranging from 6.3e^-7 erg cm^-2 to 7.0e^-7 erg cm^-2 (assuming as spectral model a power law with photon index 1.4). The AGILE-MCAL detector is a CsI detector with a 4-pi FoV, working in the range 0.4 - 100 MeV. Additional analysis of AGILE data is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21435 SUBJECT: LIGO/Virgo G296853: MASTER follow up observations DATE: 17/08/09 14:22:10 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.M. Lipunov, E. Gorbovskoy, V.G.Kornilov, N.Tyurina, V.Shumkov, D.Kuvshinov, P.Balanutsa, O.Gress, A.Kuznetsov, M.I.Panchenko, A.V.Krylov, I.Gorbunov Lomonosov Moscow State University, Sternberg Astronomical Institute R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA) , National University of San Juan, Argentina H. Levato, C. Saffe Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San Juan, Argentina N.M. Budnev, O. Gress, K. Ivanov, S.Yazev Irkutsk State University V.Yurkov, Yu.Sergienko, A.Gabovich Blagoveschensk Educational State University, Blagoveschensk D.Buckley, S. Potter, M. Kotze, South African Astronomical Observatory R. Rebolo, M. Serra-Ricart, G. Israelian, N.Lodiu The Instituto de Astrofisica de Canarias A. Tlatov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory MASTER I robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in OAFA (Argentina) was starting survey on the LVC G296853 error-box 2548 sec after notice time and 5501 sec after trigger time at 2017-08-09 10:00:02 UT. The 5-sigma upper limit on our first (180s exposure) set is about 19.1 mag The covering map will be available at GraceDB. Object: Altitude: 71.13 Azimuth: 124.74 Sun: Altitude: -16.84 Azimuth: 261.53 Moon: Altitude: 30.34 Azimuth: 96.86 The object can be observed till sunrise at 2017-08-09 11:19:18 UT. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21436 SUBJECT: LIGO/Virgo G296853: Swift/BAT data search DATE: 17/08/09 16:34:28 GMT FROM: Amy Lien at GSFC/Swift 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(ASDC), S. Emery (UCL-MSSL), P.A. Evans (U. Leicester), P. Giommi (ASI), C. Gronwall (PSU), J. A. Kennea (PSU), H.A. Krimm (CRESST/GSFC/USRA), N.P.M. Kuin (UCL-MSSL), F.E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), B. Mingo (U. Leicester), 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. 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: We report the search results in the BAT data within T0 +/- 100 s of the LIGO event G296853 (LIGO/VIRGO Collaboration GCN Circ. 21431), where T0 is the LIGO trigger time (2017-08-09T08:28:21.747 UTC). The center of the BAT FOV at T0 is RA = 305.082 deg, DEC = 43.799 deg, ROLL = 340.755 deg. At T0, the BAT Field of View (>10% partial coding) covers 0.01% of the integrated LIGO localization probability. That is, there is no overlap between the BAT field of view and the LIGO probability region at T0. 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, respectively. 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 ~ 1.38 x 10^-7 erg/s/cm^2. BAT retains decreased, but significant, sensitivity to rate increases for gamma-ray events outside of its FOV. About 99.88% of the integrated LIGO 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 of those within the FOV. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21437 SUBJECT: LIGO/Virgo G296853: AGILE GRID observations DATE: 17/08/09 16:48:55 GMT FROM: Francesco Verrecchia at ASDC, INAF-OAR F. Verrecchia (SSDC and INAF/OAR), G. Piano (INAF/IAPS), M. Pilia (INAF/OA-Cagliari), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Ursi (INAF/IAPS), M. Cardillo, A. Bulgarelli (INAF/IASF-Bo), C. Pittori (SSDC and INAF/OAR), N. Parmiggiani (INAF/IASF-Bo), I. Donnarumma (ASI), A. Giuliani (INAF/IASF-Mi), F. Lucarelli (ASDC and INAF/OAR), G. Minervini (INAF/IAPS), F. Longo (Univ. Trieste and INFN Trieste), F. Fuschino (INAF/IASF-Bo), Y. Evangelista (INAF/IAPS), M. Marisaldi (INAF/IASF-Bo and Bergen University), A. Argan (INAF/IAPS), A. Trois (INAF/OA-Cagliari), V. Fioretti (INAF/IASF-Bo), report on behalf of the AGILE Team: In response to the LIGO/Virgo GW trigger G296853 (GCN #21431), we performed an analysis of the AGILE Gamma-Ray Imaging Detector (GRID) data on different timescales. On LIGO trigger time (T0=2017-08-09 08:28:21.747 UTC) the GRID exposure covered more than the 95% of the LIGO localization region, observed at off-axis angles between 5 and 55 deg. An analysis of the data in the energy range 50 MeV - 10 GeV was performed on timescales from 2 to 100 sec centered at T0. Preliminary values of 3-sigma upper limits (UL) obtained within the accessible G296853 localization region are reported below: from 1.4e-06 to 6.0e-06 erg cm^-2 s^-1 for integration time of 2s from 1.4e-07 to 5.6e-07 erg cm^-2 s^-1 for integration time of 20s from 3.1e-08 to 8.4e-08 erg cm^-2 s^-1 for integration time of 100s These ULs apply to a large fraction of the GRID-exposed LIGO localization region. 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: 21438 SUBJECT: LIGO/Virgo G296853: Fermi GBM Observations DATE: 17/08/09 17:03:59 GMT FROM: Adam Goldstein at Fermi/GBM A. Goldstein (USRA) reports on behalf of the GBM-LIGO Group: L. Blackburn (CfA), M. S. Briggs (UAH), J. Broida (Carleton College), E. Burns (NASA/GSFC), J. Camp (NASA/GSFC), T. Dal Canton (NASA/GSFC), N. Christensen (Carleton College), V. Connaughton (USRA), R. Hamburg (UAH), C. M. Hui (NASA/MSFC), P. Jenke (UAH), D. Kocevski (NASA/MSFC), N. Leroy (LAL), T. Littenberg (NASA/MSFC), J. McEnery (NASA/GSFC), R. Preece (UAH), J. Racusin (NASA/GSFC), P. Shawhan (UMD), K. Siellez (GATech), L. Singer (NASA/GSFC), J. Veitch (Birmingham), P. Veres (UAH), C. Wilson-Hodge (NASA/MSFC) At the G296853 event time, GBM was taking data and viewing the entire un-occulted sky approximately 67 degrees from Earth center (RA = 66.9, DEC = +23.4), which includes 49% of the LIGO Bayestar probability map. There was a single GBM on-board trigger within 1 hour after the event time. However, this trigger was likely due to a terrestrial gamma-ray flash and unrelated to the G296853 event. The untargeted ground-based search of GBM data for short-duration GRBs (Briggs et al., in prep) found a low-reliability short GRB candidate ~76 minutes after the G296853 event time, although the localization of this candidate is entirely inconsistent with the Bayestar map. The targeted search of the GBM data ([1], [2]) also did not find a significant gamma-ray signal. This search processes time scales of 0.256 to 8.192 s within 30 s of the LIGO event. No interesting gamma-ray candidate was found within this time window. Further analysis and upper limits will be reported later. [1] L. Blackburn et al. 2015, ApjS 217, 8 [2] A. Goldstein et al. arXiv:1612.02395 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21439 SUBJECT: LIGO/Virgo G296853: Fermi-LAT search for high-energy gamma-ray counterpart DATE: 17/08/09 20:07:38 GMT FROM: Giacomo Vianello at Stanford U/Fermi LAT F.Longo (University and INFN, Trieste), N.Omodei, G.Vianello (Stanford), D.Kocevski (NASA/MSFC) and S.Buson (NASA/GSFC) report on behalf of the Fermi-LAT team: We have searched data collected by the Fermi Large Area Telescope (LAT) for possible high-energy (E > 100 MeV) gamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo trigger G296853. At the time of the trigger (T0 = 2017-08-09 02:01:16.492 UTC, 523960106.748 MET), none of the LIGO Bayestar probability map was in the LAT field of view. Part of the region entered the LAT field of view 1700 seconds after T0, and we reached 100% cumulative coverage within ~2.7 ks after the trigger. 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. We performed a search for a transient counterpart within the 90% contour of the LIGO map in the time window from T0 to T0 + 10 ks. We also performed a search which adapted the time interval of the analysis to the exposure of each region of the sky. No significant candidate counterpart was found. Similarly, the Automated Science Processing search, which looks for variation in flux from known sources and for new transients on different time scales (Chiang 2012), did not detect any new transient consistent within the 90% contour of the G296853 map, during a six-hour interval from T0-2hr to T0+4hr. The Fermi-LAT point of contact for this event is Francesco Longo (francesco.longo@ts.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: 21440 SUBJECT: LIGO/Virgo G296853: no INTEGRAL data at the time of the event DATE: 17/08/09 21:13:12 GMT FROM: Carlo Ferrigno at ISDC/INTEGRAL C. Ferrigno (ISDC, University of Geneva, CH) on behalf of the INTEGRAL group: V. Savchenko (ISDC, University of Geneva, CH) S. Mereghetti (IASF-Milano, Italy), E. Kuulkers (ESTEC/ESA, The Netherlands), A. Bazzano (IAPS-Roma, Italy), E. Bozzo, T. J.-L. Courvoisier (ISDC, University of Geneva, CH) S. Brandt (DTU - Denmark) R. Diehl (MPE-Garching, Germany) L. Hanlon (UCD, Ireland) P. Laurent (APC, Saclay/CEA, France) A. Lutovinov (IKI, Russia) J.P. Roques (CESR, France) R. Sunyaev (IKI, Russia) P. Ubertini (IAPS-Roma, Italy) The INTEGRAL satellite requires continuous contact between the spacecraft and a ground station for operations and data down-link. Unfortunately, at the time of the LIGO/Virgo trigger G296853 (2017-08-09 08:28:21.747 UTC), there was a scheduled ground-station outage. Therefore, no INTEGRAL data are available on 2017-08-09 between 06:40:13 and 12:24:39 UTC, preventing any investigation of the presence of an electromagnetic signal temporally coincident with this gravitational wave trigger. The field of view of the imaging instruments has not covered the high-probability region of the LIGO event at any time after the trigger and it will not in the coming days. As a consequence, no search of a possible GRB afterglow-like signal is foreseeable. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21445 SUBJECT: LIGO/Virgo G296853: MASTER SN detection near center error-area DATE: 17/08/10 16:40:38 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.M. Lipunov, E. Gorbovskoy, V.G.Kornilov, N.Tyurina, V.Shumkov, D.Kuvshinov, P.Balanutsa, O.Gress, A.Kuznetsov, M.I.Panchenko, A.V.Krylov, I.Gorbunov Lomonosov Moscow State University, Sternberg Astronomical Institute R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA) , National University of San Juan, Argentina H. Levato, C. Saffe Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San Juan, Argentina N.M. Budnev, O. Gress, K. Ivanov, S.Yazev Irkutsk State University V.Yurkov, Yu.Sergienko, A.Gabovich Blagoveschensk Educational State University, Blagoveschensk D.Buckley, S. Potter, M. Kotze, South African Astronomical Observatory R. Rebolo, M. Serra-Ricart, G. Israelian, N.Lodiu The Instituto de Astrofisica de Canarias A. Tlatov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory MASTER OT J013646.48-140323.5 discovery - PSN in 6.3"E,13.1"S of barred spiral PGC005976 During LIGO G296853 area inspection MASTER-SAAO(see Lipunov et al., GCN 21435) auto-detection system (Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered possible SuperNova explosion in PGC005976 galaxy at position (RA, Dec) = 01h 36m 46.48s -14d 03m 23.5s on 2017-08-09.91543 UT (Gress et al., Atel #10631). The OT (PSN) unfiltered magnitude is 17.1m (mlim=18.8). This OT is seen in 4 inspection images. There is no minor planet at this place. We have reference image on 2016-08-27.02894 UT with unfiltered mlim= 20.3m. This PSN is located in spiral in 6.3"E,13.1"S of barred PGC005976 with Btc=14.82, Vgsr=12113km/s Corresponding distance is ~ 170 Mpc. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/013646.48-140323.5.png This message can be citted. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21446 SUBJECT: LIGO/Virgo G296853: Super-AGILE observations DATE: 17/08/10 17:54:06 GMT FROM: Francesco Verrecchia at ASDC, INAF-OAR Y. Evangelista (INAF/IAPS), E. Del Monte (INAF/IAPS), F. Verrecchia (SSDC and INAF/OAR), M. Feroci (INAF/IAPS), E. Costa (ASI), A. Trois (INAF/OA-Cagliari), G. Piano (INAF/IAPS), M. Pilia (INAF/OA-Cagliari), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Ursi (INAF/IAPS), M. Cardillo, A. Bulgarelli (INAF/IASF-Bo), C. Pittori (SSDC and INAF/OAR), N. Parmiggiani (INAF/IASF-Bo), I. Donnarumma (ASI), A. Giuliani (INAF/IASF-Mi), F. Lucarelli (ASDC and INAF/OAR), G. Minervini (INAF/IAPS), F. Longo (Univ. Trieste and INFN Trieste), F. Fuschino (INAF/IASF-Bo), M. Marisaldi (INAF/IASF-Bo and Bergen University), A. Argan (INAF/IAPS), V. Fioretti (INAF/IASF-Bo), report on behalf of the AGILE Team: In response to the LIGO/Virgo GW trigger G296853 (GCN #21431, T0=2017-08-09 08:28:21.747 UTC) we analyzed the AGILE/Super-AGILE (SA) photon-by-photon data obtaining no significant detection in the 20-60 keV light curve for the interval T0 +/- 100s with different bin sizes (from 0.05 s to 16 s). The Super-AGILE FoV covered about 20% of the LIGO 90% localization region, observed at off-axis angles between 10 and 35 deg. A 3-sigma upper-limit (UL) in the 20-60 keV energy band has been derived for an integration time of 1 s, and varies between 2.2 x 10^-8 erg cm^-2 for 10° off-axis position to 7.0 x10^-8 erg cm^-2 at 30° off-axis position. These measurements were obtained with AGILE observing a large portion of the sky in spinning mode. Additional analysis of SuperAGILE data is in progress. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21448 SUBJECT: LIGO/Virgo G296853: HAWC follow-up DATE: 17/08/10 19:10:13 GMT FROM: Israel Martinez-Castellanos at UMD/HAWC I. Martinez-Castellanos (University of Maryland, College Park) and A.J. Smith (University of Maryland, College Park) on behalf of the HAWC Collaboration: HAWC performed a follow-up of LIGO trigger G296853. At the time of the trigger only a small portion (6%) of the probability distribution overlapped with HAWC field of view (FOV), and it was located at a large zenith angle where the sensitivity is poorest. The real-time search was preformed and identified no candidate counterparts. Additionally we searched for longer duration emission integrating the next transit of the LIGO contour through HAWC's FOV. The most probable location transited 1-3hrs after the trigger (~41deg from zenith at culmination). In total, 52% of the LIGO probability contour was observed. There were no significant detections (5-sigma). HAWC is a TeV gamma ray water Cherenkov array located in the state of Puebla, Mexico. It is sensitive to the energy range ~0.5-100TeV, and monitors 2/3 of the sky every day with an instantaneous field-of-view of ~2 sr. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21456 SUBJECT: LIGO/Virgo G296853 : MAXI/GSC observations DATE: 17/08/11 11:48:06 GMT FROM: Satoshi Sugita at Tokyo Inst. of Tech. S. Sugita, N. Kawai (Tokyo Tech), M. Serino (RIKEN), H. Negoro (Nihon U.), S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N.Isobe, R. Shimomukai (JAXA), T. Mihara, M. Sugizaki, S. Nakahira, W. Iwakiri, M. Shidatsu, M. Matsuoka (RIKEN), T. Yoshii, Y. Tachibana, S. Harita, Y. Muraki, K. Morita (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, Y. Kitaoka, T. Hashimoto (AGU), H. Tsunemi, T. Yoneyama (Osaka U.), M. Nakajima, T. Kawase, A. Sakamaki (Nihon U.), Y. Ueda, T. Hori, A. Tanimoto, S. Oda (Kyoto U.), Y. Tsuboi, Y. Nakamura, R. Sasaki (Chuo U.), M. Yamauchi, C. Hanyu, K, Hidaka (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team: We examined the MAXI/GSC all-sky X-ray images (2-20 keV) obtained in the orbit and the day after the LVC trigger G296853 at 2017-08-09 08:28:21.747 UTC (GCN 21431). At the trigger time of G296853, the high-voltage of MAXI/GSC was off, and it was turned on at T0+1114 sec. GSC scanned more than 83% of the whole sky in the 92-min orbit, which includes 92.7% of the 90% region in the bayestar skymap scanned from 08:49:51 to 09:00:11 UTC (T0+1289 to 1909 sec). One day image obtained between 08-09 08:49:51 and 08-10 08:09:40 UTC covers 100% of the 90% region in the bayestar skymap. No significant new source was found in these images. The 2-20 keV 1-sigma (3-sigma) averaged upper limits obtained from the one-orbit and one-day images in the bayestar skymap are 12(36) and 3(9) mCrab, respectively. If you require information of X-ray flux by MAXI/GSC at specific coordinates, please contact the submitter of this circular by email. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21457 SUBJECT: LIGO/Virgo G296853: Insight-HXMT observations DATE: 17/08/11 14:41:44 GMT FROM: Shaolin Xiong at IHEP J. Y. Liao, X. B. Li, C. K. Li, M. Y. Ge, Y. Huang, S. L. Xiong, Y. Liu, C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu, J. L. Zhao, A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, H. Y. Wang, 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 LIGO trigger time (T0=2017-08-09 08:28:21.747 UTC). At T0, more than 95% of the LIGO localization region was covered by the Insight-HXMT without occultation by the Earth. Within T0 +/- 1000 s, no significant events (SNR > 5 sigma) are found in a search of the Insight-HXMT raw light curves with time scales of 20 ms, 50 ms, 0.2 s and 1 s, respectively. Only one particle event lasting about 180 s was found at T0-680 s, which is caused by the orbital environment thus has no relation with the LIGO event. With the three typical GRB Band spectral models, three integration time (1 s, 10 s, and 100 s) and the LIGO localization region, the 3-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): 1s: 1.4e-07 to 2.6e-07 erg cm^-2 10s: 4.5e-07 to 9.1e-07 erg cm^-2 100s: 1.6e-06 to 3.1e-06 erg cm^-2 Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV): 1s: 2.2e-07 to 3.9e-07 erg cm^-2 10s: 7.2e-07 to 1.4e-06 erg cm^-2 100s: 2.5e-06 to 4.6e-06 erg cm^-2 Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV): 1s: 5.2e-07 to 7.5e-07 erg cm^-2 10s: 1.6e-06 to 2.5e-06 erg cm^-2 100s: 5.8e-06 to 8.4e-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 (record 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 telescope. The analysis results presented above are preliminary; refined results will be reported later. 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 about it could be found at: http://www.hxmt.org/index.php/enhome . //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21459 SUBJECT: LIGO/Virgo G296853: BOOTES-1 and GTC optical observations DATE: 17/08/11 17:02:15 GMT FROM: Alberto J. Castro-Tirado at IAA-CSIC A. J. Castro-Tirado (IAA-CSIC and ISA-UMA), C. PĂ©rez del Pulgar and R. MartĂ­n Márquez (ISA-UMA), A. CastellĂłn (UMA), M. JelĂ­nek (ASU-CAS), R. Cunniffe, Y. Hu and A. González-RodrĂ­guez (IAA-CSIC), P. Peseev, G. GĂłmez and A. Alonso (GRANTECAN), on behalf of a larger collaboration report: In response to the LIGO/Virgo GW Binary Merger Candidate G296853 on Aug 9, 08:28 UT (GCNC 21431), a mosaic of unfiltered images covering 80% of the GraceDB skymap (above -45 in Dec) was taken starting on Aug 10, 01:30 UT (i.e. 17 hr later) with the wide-field imager at the BOOTES-1 station located at the ESAt/INTA-CEDEA in MazagĂłn (Huelva, Spain), down to a R = 12 limiting magnitude. In addition to this, data for several selected fields within the skymap center were gathered the same night with the 10.4m GTC telescope (+OSIRIS spectrograph) in riz filters down to R = 21.5, with the images quality being affected by the nearby full moon and the poor transparency due to the dust from Sahara. A more detailed analysis of the data is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21467 SUBJECT: LIGO/Virgo G296853: Liverpool Telescope classification of MASTER OT J013646.48-140323.5 DATE: 17/08/12 19:54:24 GMT FROM: Chris Copperwheat at LJMU ArI C.M.Copperwheat (LJMU), I.A.Steele (LJMU) reports on behalf of D.Bersier (LJMU), M.Bode (LJMU), C.Collins (LJMU), M.Darnley (LJMU), D.Galloway (Monash), A.Gomboc (Nova Gorica), S.Kobayashi (LJMU), A. Levan (Warwick), P.Mazzali (LJMU), C.Mundell (Bath), E.Pian (Pisa), D. Pollacco (Warwick), D. Steeghs (Warwick), N.Tanvir (Leicester), K. Ulaczyk (Warwick), K.Wiersema (Leicester) and the GROWTH (Global Relay of Observatories Watching Transients Happen) collaboration. --- We observed MASTER OT J013646.48-140323.5, originally reported in GCN #21445, on 2017-08-12 at 03:25UT using the SPRAT spectrograph on the Liverpool Telescope. The spectra we obtain are fairly poor quality due to the proximity of the moon. Using SNID (Blondin & Tonry, 2007, ApJ, 666, 1024) we tentatively classify this transient as a SN Ia or Ib at around 7 days before peak, with a redshift consistent with the distance of the nearby galaxy (170Mpc, as reported in GCN #21445). -- ------------------------------------------------------ C.M.Copperwheat Astrophysics Research Institute, Liverpool John Moores University ------------------------------------------------------ http://telescope.livjm.ac.uk ------------------------------------------------------ Email: c.m.copperwheat@ljmu.ac.uk Tel: +44 (0)151 231 2914 Fax: +44 (0)151 231 2921 ------------------------------------------------------ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21496 SUBJECT: LIGO/Virgo G296853: Pierre Auger Observatory neutrino follow-up DATE: 17/08/16 13:42:51 GMT FROM: Jaime Alvarez-Muniz at Pierre Auger Observatory J. Alvarez-Muniz, F. Pedreira, E. Zas (Univ. Santiago de Compostela, Spain), K. H. Kampert & M. Schimp (Bergische Universitat, Wuppertal, Germany) on behalf of the Pierre Auger Collaboration. In response to the LIGO/Virgo GW trigger G296853 (GCN #21431, T0=2017-08-09 08:28:21.747 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 G296853 as well as 1 day after it. 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 NOT coincident with the LIGO 90% localization region at the time T0 of the merger alert. The LIGO 90% localization region maximally overlapped with the Auger fov for the first time ~ 7 hours after the merger. 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 from GW events with Auger, please refer to: https://journals.aps.org/prd/pdf/10.1103/PhysRevD.94.122007 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21501 SUBJECT: LIGO/Virgo G296853 TZAC TAROT observations DATE: 17/08/17 08:38:15 GMT FROM: Michel Boer at CESR-CNRS A. Klotz (IRAP/CNRS/UPS), R. Laugier (ARTEMIS/CNRS/UCA/OCA), K. Noysena (ARTEMIS/IRAP), M. Boer (ARTEMIS/CNRS/UCA/OCA) report on behalf of the TZAC collaboration: The field of the LVC candidate event G296853 was observed with TCH (TAROT-Chile field 1.9 x 1.9 deg2), TCA (TAROT Calern, field 1.9 x 1.9deg2) and TRE (TAROT La RĂ©union field 4.0 x 4.0 deg2) from Aug. 9, 2017 at 10h10m11s UT to Aug. 11, 2017, at 1h52m39s under good to variable conditions. 122 images lasting 120s each where generated. Fields observed at least twice have been checked for new sources with an upper limit of R > 17.5. For the other fields the analysis is still in progress. List of fields that were observed, centered on (RA, DEC) : TCH: 19.242 -20.171, 18.001 -22.035, 20.079 -22.035 from 2017-08-09T10:10:11 to 2017-08-09T10:36:30 TCA: 19.514 -20.193, 20.369 -22.057, 18.368 -22.060 from 2017-08-10T00:39:49 to 2017-08-10T02:40:38 TCH: 18.061 -22.126, 20.074 -22.119, 19.227 -20.264 from 2017-08-10T02:40:38 to 2017-08-10T04:17:29 TRE: 18.996 -30.232, 20.632 -26.034, 19.565 -30.232, 20.966 -26.033, 18.161 -34.430, from 2017-08-10T21:58:50 to 2017-08-11T01:50:39 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21697 SUBJECT: LIGO/Virgo G296853: VLT observations by GLGW Hunters DATE: 17/08/25 15:34:40 GMT FROM: Graham P Smith at U of Birmingham M. Jauzac (Durham), G. P. Smith (Birmingham), J. Richard (Lyon), M. Bianconi (Birmingham), C. P. L. Berry (Birmingham), W. M. Farr (Birmingham), R. Massey (Durham), A. Robertson (Durham), K. Sharon (Michigan), A. Vecchio (Birmingham), J. Veitch (Glasgow) The Gravitationally-lensed Gravitational Wave Hunters collaboration report observations of strong-lensing galaxy clusters located within the sky localisation of the LIGO/Virgo trigger G296853 (LVC GCN Circ. 21413). Following Smith et al. (arXiv:1707.03412) we searched the skymap for strong-lensing galaxy clusters that lie within the 90% credible sky localisation. Abell 2895 was the closest strong-lensing galaxy cluster to the peak probability in the skymap. We observed this cluster with MUSE on VLT on the nights of August 9, 14, and 16. MUSE spans a 1x1 arcminute field of view with a wavelength range of 4650-9300 Angstroms. Analysis of these data is ongoing. Colleagues with complementary data are welcome to contact us with a view to collaboration. We thank the staff at ESO for their outstanding support of our observing programmes. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21748 SUBJECT: LIGO/Virgo G296853: PIRATE observations DATE: 17/08/29 12:59:11 GMT FROM: Dean Roberts at PIRATE D. Roberts, U. Kolb & M.Morrell (The Open University) reporting on behalf of the PIRATE group: We observed 34 separate fields within the bayestar skymap of the LIGO/Virgo candidate G296853 using our 0.43m robotic telescope at Teide Observatory, Tenerife, Spain. We acquired over 768 images across 7 nights of observations, all images were obtained using the R filter and 60s exposure length. Initial observations began at 2017-08-10T02:24:29, approximately 17 hours after the initial GCN alert was received. A detailed list of all the fields observed can be found on GraceDB under the EMObservations tab. Preliminary analysis suggests no new transients were detected in any of the observing fields down to a limiting magnitude ~18. Further analysis is ongoing. -- The Open University is incorporated by Royal Charter (RC 000391), an exempt charity in England & Wales and a charity registered in Scotland (SC 038302). The Open University is authorised and regulated by the Financial Conduct Authority in relation to its secondary activity of credit broking.