April 2024 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 34099] LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
by GCN Circulars 23 Apr '24

23 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36256 SUBJECT: LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations DATE: 24/04/23 14:44:02 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma <rosa.becerra(a)roma2.infn.it> Rosa L. Becerra (UTOV), Alan M. Watson (UNAM), Simone Dichiara (PSU), Eleonora Troja (UTOV), Nat Butler (ASU), William H. Lee (UNAM), Alexander Kutyrev (GSFC/UMD), Tsvetelina Dimitrova (ASU), Keneth Garcia Cifuentes (UNAM), Camila Angulo Valdez (UNAM), Margarita Pereyra (UNAM) and Océlotl Lopez (UNAM) report: We observed LIGO/Virgo/KAGRA S240422ed (GCN #36236) with the DDOTI/OAN wide-field imager at the Observatorio Astronomico Nacional on Sierra San Pedro Martir (http://ddoti.astroscu.unam.mx) on the night of 2024-04-23 UTC. We tiled the LVK localization with two pointings covering about 104 square degrees and including about 42% of the probability in the current BAYESTAR map. We observed from 2024-04-23 03:15 UTC to 2024-04-23 05:04 UTC (from T+5.7 to T+7.5 hours after the event) obtaining a total of 54 minutes of exposure across the fields in the w filter, with 10-sigma limiting magnitudes of w~19 and constrained by the horizon. Comparing our observations to the USNO-B1 and PanSTARRS PS1 DR2 catalogs we detect no uncatalogued sources within the observed field to our 10-sigma limit. Further observations are planned. We thank the staff of the Observatorio Astronomico Nacional in San Pedro Martir. View this GCN Circular online at https://gcn.nasa.gov/circulars/36256. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 34098] GRB 240419A: Swift-BAT refined analysis
by GCN Circulars 23 Apr '24

23 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36255 SUBJECT: GRB 240419A: Swift-BAT refined analysis DATE: 24/04/23 13:00:27 GMT FROM: Mike Moss at NASA GSFC <mikejmoss3(a)gmail.com> T. Parsotan (GSFC), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. H. Siegel (PSU) (i.e. the Swift-BAT team): Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 240419A (trigger #1222955) (Siegel, et al., GCN Circ. 36169). The BAT ground-calculated position is RA, Dec = 94.505, -44.964 deg which is RA(J2000) = 06h 18m 01.3s Dec(J2000) = -44d 57' 50.2" with an uncertainty of 3.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 89%. The mask-weighted light curve shows two dim pulses at T0-7 s and T0+0 s, respectively. The T90 (15-350 keV) is 3.00 +- 1.41 sec (estimated error including systematics). The time-averaged spectrum from T-0.43 to T+2.57 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.71 +- 0.38. The fluence in the 15-150 keV band is 8.4 +- 2.1 x 10^-08 erg/cm2. The 1-sec peak photon flux measured from T+0.57 sec in the 15-150 keV band is 0.6 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1222955 View this GCN Circular online at https://gcn.nasa.gov/circulars/36255. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 34097] GRB 240418A: Swift-BAT refined analysis
by GCN Circulars 23 Apr '24

23 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36254 SUBJECT: GRB 240418A: Swift-BAT refined analysis DATE: 24/04/23 12:59:27 GMT FROM: Mike Moss at NASA GSFC <mikejmoss3(a)gmail.com> D. M. Palmer (LANL), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), T. Parsotan (GSFC), T. Sakamoto (AGU), M. H. Siegel (PSU) (i.e. the Swift-BAT team): Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 240418A (trigger #1222885) (Siegel, et al., GCN Circ. 36162). The BAT ground-calculated position is RA, Dec = 239.342, 23.632 deg which is RA(J2000) = 15h 57m 22.0s Dec(J2000) = +23d 37' 54.4" with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 79%. The mask-weighted light curve shows a single, dim pulse peaking at T0+5 s. The T90 (15-350 keV) is 12.00 +- 3.61 sec (estimated error including systematics). The time-averaged spectrum from T-0.47 to T+12.53 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.99 +- 0.31. The fluence in the 15-150 keV band is 2.3 +- 0.5 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+4.53 sec in the 15-150 keV band is 0.5 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1222885 View this GCN Circular online at https://gcn.nasa.gov/circulars/36254. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 34096] LXT240402A/GRB240402B: Chandra X-ray detection
by GCN Circulars 23 Apr '24

23 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36253 SUBJECT: LXT240402A/GRB240402B: Chandra X-ray detection DATE: 24/04/23 12:55:40 GMT FROM: muskan.yadav(a)students.uniroma2.eu M. Yadav, E. Troja, Y. -H. Yang, and R. L. Becerra (U. Rome) report: Following the detection of the fast X-ray transient LXT 240402A (Xu et al., GCN 36016) associated with GRB 240402B (Wang et al., GCN 36017), we performed observations of the field with the Chandra X-ray Observatory starting at UT 00:48 on April 15, 2024 for a total exposure of 16 ks. An X-ray source is detected with high significance at the location of the optical counterpart (Yang at al., GCN 36094). Using the spectral parameters of the EP-FXT detection (Jia et al., GCN 36022) we derive an X-ray flux of 8*10^-14 erg s^-1 cm^-2 (0.5-10 keV), consistent with the Swift/XRT observations (Martin-Carrillo et al., GCN 36114). We thank Pat Slane and the CXO staff for quickly arranging and executing the observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/36253. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 34095] LIGO/Virgo/KAGRA S240423br: Retraction of GW compact binary merger candidate
by GCN Circulars 23 Apr '24

23 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36252 SUBJECT: LIGO/Virgo/KAGRA S240423br: Retraction of GW compact binary merger candidate DATE: 24/04/23 11:54:40 GMT FROM: Irina Dvorkin <dvorkin(a)iap.fr> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: The trigger S240423br is no longer considered to be a candidate of interest. Looking at the data, the trigger was due to non-stationary noise in the LIGO Livingston detector. Pipeline and data quality experts recommended a retraction. View this GCN Circular online at https://gcn.nasa.gov/circulars/36252. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 34094] LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from ATLAS observations
by GCN Circulars 23 Apr '24

23 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36251 SUBJECT: LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from ATLAS observations DATE: 24/04/23 11:29:53 GMT FROM: S. Srivastav at Oxford <shubhamsrivastav(a)gmail.com> S. Srivastav (Oxford), S. J. Smartt (QUB/Oxford), K. W. Smith, D. R. Young, M. Nicholl, M. D. Fulton, T. Moore, A. Aamer, C. R. Angus, M. McCollum, S. Sim, J. Weston, X. Sheng (QUB), L. Shingles (GSI/QUB), J. Sommer (LMU/QUB), J. Gillanders, H. Stevance, L. Rhodes, A. Andersson (Oxford), L. Denneau, J. Tonry, H. Weiland, A. Lawrence, R. Siverd (IfA, University of Hawaii), N. Erasmus, W. Koorts (South African Astronomical Observatory), J. Anderson (ESO), A. Jordan, V. Suc (UAI, Obstech) A. Rest (STScI), T.-W. Chen (NCU), C. Stubbs (Harvard): We report observations of the skymap of the NSBH/BNS merger event S240422ed (The LIGO-Virgo-Kagra Collaboration, GCN 36236) with the ATLAS survey (Tonry et al., 2018, PASP, 13, 164505). ATLAS is a quadruple 0.5m optical telescope survey system (Hawaii, South Africa, Chile) employing two filters, cyan and orange. In our primary NASA mission for Near-Earth Object discovery, we cover the entire visible night sky every 24 hrs to magnitude depths m ~ 19.5, weather and Moon permitting. We targeted the accessible skymap of S240422ed with a sequence of quads (4 x 110 s images) obtained at each pointing position. Data acquisition began at MJD 60422.9653 or 2024-04-22 23:10:01.920 (UTC), 0.8 hrs after the LVC initial alert and 1.6 hrs after the merger event. The images were processed with the ATLAS pipeline, and reference images were subtracted. Transient candidates were identified and run through our standard filtering procedures (Smith et al., 2020, PASP, 132, 1). We covered 242 square degrees of the bilby.fits skymap 90% area, and covered a sky region totalling 77% of the event's full localisation likelihood. Observations lasted between ~1.6 hrs to 7.2 hrs after the NSBH/BNS merger. We found no plausible new transient sources that had not been previously detected by ATLAS before the merger event or reported to the IAU Transient name server. The 5-sigma depths of our images were typically 18.7 < m_o < 19.5 AB mag. We are reporting all discoveries to the TNS, where they can be tracked, classified, searched, and commented upon. We encourage further information to be reported on the TNS object pages. The Asteroid Terrestrial-impact Last Alert System (ATLAS) project is primarily funded to search for Near-Earth asteroids through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; byproducts of the NEO search include images and catalogs from the survey area. This work was partially funded by Kepler/K2 grant J1944/80NSSC19K0112 and HST GO-15889, and STFC grants ST/T000198/1 and ST/S006109/1. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen's University Belfast, the Space Telescope Science Institute, the South African Astronomical Observatory, and The Millennium Institute of Astrophysics (MAS), Chile. View this GCN Circular online at https://gcn.nasa.gov/circulars/36251. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 34093] GRB 240419A: Possible ATCA radio detection
by GCN Circulars 23 Apr '24

23 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36250 SUBJECT: GRB 240419A: Possible ATCA radio detection DATE: 24/04/23 09:51:22 GMT FROM: Gemma Anderson at Curtin U <gemma.anderson(a)curtin.edu.au> S. Chastain (UNM), G. E. Anderson (Curtin University), J. K. Leung (U. Toronto/HUJI), L. Rhodes (U. Oxford), S. D. Ryder (Macquarie), A. Gulati (U. Sydney), A. J. van der Horst (GWU), on behalf of the PanRadio GRB collaboration The Australia Telescope Compact Array (ATCA) performed rapid follow-up observations of GRB 240419A (Siegel et al., GCN 36169) at 5.5, 9, and 18 GHz as part of the Long-term ATCA "PanRadio GRB" follow-up programme C3542 (PI. Anderson). ATCA began observing at 2024-04-19 04:00 UT (2.2 hours post-burst) up until 12:30 UT. In our preliminary analysis, we have a marginal detect of 63 +/- 18 microJy/beam at 18 GHz that is coincident with the enhanced XRT position (Goad et al., GCN 36174). We obtain 3 sigma upper limits of 39 and 42 microJy/beam at 5.5 and 9.0, respectively. Further observations are planned. We thank the CSIRO Space and Astronomy staff for supporting these observations. We acknowledge the Gomeroi people as the traditional owners of the Observatory site. The Australia Telescope Compact Array is part of the Australia Telescope National Facility (https://ror.org/05qajvd42) which is funded by the Australian Government for operation as a National Facility managed by CSIRO. View this GCN Circular online at https://gcn.nasa.gov/circulars/36250. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 34092] GRB 240421B: ATCA radio observations
by GCN Circulars 23 Apr '24

23 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36249 SUBJECT: GRB 240421B: ATCA radio observations DATE: 24/04/23 09:50:08 GMT FROM: Gemma Anderson at Curtin U <gemma.anderson(a)curtin.edu.au> G. E. Anderson (Curtin University), L. Rhodes (U. Oxford), J. K. Leung (U. Toronto/HUJI), S. Chastain (UNM), A. Gulati (U. Sydney), A. J. van der Horst (GWU), on behalf of the PanRadio GRB collaboration The Australia Telescope Compact Array (ATCA) performed rapid-response observations of GRB 240421B (Williams et al., GCN 36208) at 5.5, 9, 16.7 and 21.2 GHz as part of the Long-term ATCA "PanRadio GRB" follow-up programme C3542 (PI. Anderson). ATCA observed from 2024-04-21 17:00 UT (7.3 hours post-burst) to 2024-04-22 01:40 UT. In our preliminary analysis, we find no radio source coincident with the enhanced XRT position (Beardmore et al., GCN 36213) with 3 sigma upper limits of 57, 54, 60, 90 microJy/beam at 5.5, 9.0, 16.7 and 21.2 GHz, respectively. We thank the CSIRO Space and Astronomy staff for supporting these observations. We acknowledge the Gomeroi people as the traditional owners of the Observatory site. The Australia Telescope Compact Array is part of the Australia Telescope National Facility (https://ror.org/05qajvd42) which is funded by the Australian Government for operation as a National Facility managed by CSIRO. View this GCN Circular online at https://gcn.nasa.gov/circulars/36249. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 34091] LIGO/Virgo/KAGRA S240422ed: WINTER near-infrared J-band observations
by GCN Circulars 23 Apr '24

23 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36248 SUBJECT: LIGO/Virgo/KAGRA S240422ed: WINTER near-infrared J-band observations DATE: 24/04/23 08:10:26 GMT FROM: Viraj Karambelkar at Indian Inst of Tech,Bombay <karambelkarvraj21197(a)gmail.com> Viraj Karambelkar (Caltech), Geoffrey Mo (MIT), Robert Stein (Caltech), Nathan Lourie (MIT), Danielle Frostig (MIT), Tomas Ahumada (Caltech), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) We observed the localization region of the LVK trigger S240422ed (GCN 36236) with the 1.2 sq. degree WINTER camera on the Palomar 1-m telescope (Lourie et al. 2021). We obtained images in the near-IR J-band of the Bilby sky map (GCN 36240). Our observations began at 2024-04-23T03:04 UTC, ~5.5 hours after the GW event time, and lasted for ~2.5 hours. Our observations covered ~14% of the localization probability, and achieved a 5-sigma depth ranging between m_J = 16 - 17 mag (AB) depending on the sensor temperature. The observations have been reported to TreasureMap (Wyatt et al. 2020). The images were processed through the WINTER data reduction pipeline implemented using mirar (https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.10888436). We cross-matched all sources with the alert stream from the Zwicky Transient Facility (GCN 36246). We found 153 candidates and rejected them as variable stars. Further analysis is underway. WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucille Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research. View this GCN Circular online at https://gcn.nasa.gov/circulars/36248. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 34090] LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
by GCN Circulars 23 Apr '24

23 Apr '24

TITLE: GCN CIRCULAR NUMBER: 36247 SUBJECT: LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation DATE: 24/04/23 07:47:35 GMT FROM: Volodymyr Savchenko at UNIGE, EPFL <volodymyr.savchenko(a)epfl.ch> 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 S240422ed (GCN 36236). At the time of the event (2024-04-22 21:35:13 UTC, hereafter T0), INTEGRAL was operating in nominal mode. The peak of the event localization probability was at an angle of 113 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (5.6% of optimal) response of ISGRI, strongly suppressed (27% of optimal) response of IBIS/Veto, and near-optimal (72% of optimal) response of SPI-ACS. The background within +/-300 seconds around the event was rather stable (excess variance 1.3). 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 1.9e-07 erg/cm^2 (within the 50% probability containment region of the source localization) for a burst lasting less than 1 s with a characteristic short GRB spectrum (an exponentially cut off power law with alpha=-0.5 and Ep=600 keV) occurring at any time in the interval within 300 s around T0. For a typical long GRB spectrum (Band function with alpha=-1, beta=-2.5, and Ep=300 keV), the derived peak flux upper limit is ~1.7e-07 (5.4e-08) erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range. We report for completeness and in order of FAP, all excesses identified in the search region. We find: 10 likely background excesses: T-T0 | scale | S/N | flux ( x 1e-06 erg/cm2/s) | FAP -8.75 | 0.35 | 4.2 | 4.54 +/- 0.998 +/- 1.63 | 0.0646 39.6 | 2.5 | 3.2 | 1.3 +/- 0.369 +/- 0.466 | 0.225 14.7 | 0.05 | 5 | 1.47 +/- 0.274 +/- 0.526 | 0.228 46.7 | 0.45 | 3.7 | 3.49 +/- 0.877 +/- 1.25 | 0.485 -112 | 2.55 | 3.3 | 1.33 +/- 0.365 +/- 0.477 | 0.49 -25.5 | 0.5 | 3.3 | 3.03 +/- 0.83 +/- 1.09 | 0.521 -33.7 | 0.3 | 3.7 | 0.44 +/- 0.108 +/- 0.158 | 0.56 -18.7 | 0.05 | 4.1 | 1.19 +/- 0.271 +/- 0.426 | 0.607 -44.1 | 0.3 | 3.7 | 0.438 +/- 0.108 +/- 0.157 | 0.663 -46.7 | 0.5 | 3.4 | 3.08 +/- 0.831 +/- 1.1 | 0.747 Note that FAP estimates (especially at timescales above 2s) may be possibly further affected by enhanced non-stationary local background noise. This list excludes any excesses for which FAP is close to unity. We note that no independent IBAS alerts happened in the vicinity. SPI-ACS data can be retrieved and interactively explored in MMODA with this link: https://www.astro.unige.ch/mmoda/?DEC=-29.74516667&RA=265.97845833&T1=2024-… INTEGRAL follow-up alert was distributed to SCIMMA through HERMES few minutes after the trigger GCN: https://hermes.lco.global/message/4200a286-c463-437b-8363-6fd6b6df5d73 All results quoted are preliminary. This circular is an official product of the INTEGRAL Multi-Messenger team. Note that we send GCNs Circulars only when one of the following conditions is met: merger contains at least one neutron star, a singificant counterpart is reported. [1] Savchenko et al. 2017, A&A 603, A46 [2] Savchenko et al. 2012, A&A 541A, 122S View this GCN Circular online at https://gcn.nasa.gov/circulars/36247. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

2025

2024

2023

2022

2021

vsnet-grb-info April 2024