March 2025 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 38008] GRB 250330B: EIRSAT-1 GMOD Detection
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39989 SUBJECT: GRB 250330B: EIRSAT-1 GMOD Detection DATE: 25/03/31 23:14:24 GMT FROM: David Murphy at University College Dublin <david.murphy(a)ucd.ie> D. Murphy, J. Fisher, C. de Barra, P. McDermott, C. McKenna, A. Ulyanov, G. Finneran, G. Corcoran, L. Cotter, A. Empey, F. Gibson Kiely, J. Thompson, D. McKeown, A. Martin-Carrillo, L. Hanlon, S. McBreen, on behalf of the EIRSAT-1 team: EIRSAT-1 reports the detection of the short gamma-ray burst GRB 250330B by the Gamma-ray Module (GMOD) instrument, which was also detected by Fermi GBM (GCN [39951](https://gcn.nasa.gov/circulars/39951)) The GMOD detection was made starting at 2025-03-30 21:52:22.4 UTC. The GMOD light curve for GRB250330B, with 1.2s binning, shows a single peak, consistent with the detection by Fermi GBM. The spacecraft location at time of detection was 1.704 S, 7.769 E and an altitude of 407.7 km. The light curve for this event as measured by GMOD can be found here: https://grb.eirsat1.ie/250330B/250330B_LC_onboard_preliminary.png EIRSAT-1 is Ireland’s first satellite ([Doyle et al. Proceedings of the 4th SSEA, 2022](https://researchrepository.ucd.ie/bitstreams/2f3fdccb-6e36-4ac1-88cd-4e80feecf446/download)). It is a 2U CubeSat and carries onboard a number of experiments including the Gamma-Ray Module (GMOD), a novel, compact, gamma-ray detector ([Murphy et al, Experimental Astronomy, 53, 961–990, 2022](https://link.springer.com/article/10.1007/s10686-022-09842-z)) GMOD consists of a 25 mm × 25 mm × 40 mm Cerium Bromide scintillator coupled to SiPMs and is designed to detect gamma-ray bursts in the ~ 60 keV - 1.5 MeV range. EIRSAT-1 was developed in University College Dublin with support from ESA’s Fly Your Satellite! programme and was launched on 1st December 2023. View this GCN Circular online at https://gcn.nasa.gov/circulars/39989. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38007] GRB 250331E: Fermi GBM Final Real-time Localization
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39988 SUBJECT: GRB 250331E: Fermi GBM Final Real-time Localization DATE: 25/03/31 22:57:04 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 22:46:32 UT on 31 Mar 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250331E (trigger 765153997.78765 / 250331949). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 196.6, Dec = -27.7 (J2000 degrees, equivalent to J2000 13h 06m, -27d 41'), with a statistical uncertainty of 14.0 degrees. The angle from the Fermi LAT boresight is 73.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250331949/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250331949/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250331949/… View this GCN Circular online at https://gcn.nasa.gov/circulars/39988. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38006] GRB 250327A Swift-BAT refined analysis
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39987 SUBJECT: GRB 250327A Swift-BAT refined analysis DATE: 25/03/31 21:38:12 GMT FROM: Mike Moss at NASA GSFC <mikejmoss3(a)gmail.com> S. D. Barthelmy (GSFC), R. Gupta (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. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+843 sec from the recent telemetry downlink, we report further analysis of BAT GRB 250327A (trigger #1299088) (Parsotan, et al., GCN Circ. 39877). The BAT ground-calculated position is RA, Dec = 248.209, 61.610 deg which is RA(J2000) = 16h 32m 50.1s Dec(J2000) = +61d 36' 35.4" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 10%. The mask-weighted light curve shows a single main pulse lasting ~60 sec composed of several shorter pulses. The remainder of the burst emission is included in a dim tail. The T90 (15-350 keV) is 91.008 +- 12.21 sec (estimated error including systematics). The time-averaged spectrum from T+1.67 to T+109.928 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.28 +- 0.12. The fluence in the 15-150 keV band is 7.6 +- 0.5 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+24.49 sec in the 15-150 keV band is 2.1 +- 0.7 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/1299088 View this GCN Circular online at https://gcn.nasa.gov/circulars/39987. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38005] LIGO/Virgo/KAGRA S250331o: Updated Sky localization
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39986 SUBJECT: LIGO/Virgo/KAGRA S250331o: Updated Sky localization DATE: 25/03/31 19:50:46 GMT FROM: Michael J. Williams at University of Portsmouth <michael.williams(a)ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S250331o (GCN Circular 39953). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S250331o For the Bilby.multiorder.fits,0 sky map, the 90% credible region is well fit by an ellipse with an area of 18 deg2 described by the following DS9 region (right ascension, declination, semi-major axis, semi-minor axis, position angle of the semi-minor axis): icrs; ellipse(02h07m, +31d03m, 3.98d, 1.46d, 114.57d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 657 +/- 91 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 View this GCN Circular online at https://gcn.nasa.gov/circulars/39986. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38004] GRB 250329A: AbAO, Mondy and SAO RAS optical upper limits
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39985 SUBJECT: GRB 250329A: AbAO, Mondy and SAO RAS optical upper limits DATE: 25/03/31 19:48:32 GMT FROM: Alexei Pozanenko at IKI, Moscow <grb.alex(a)gmail.com> N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP), R. Ya. Inasaridze (AbAO), A. S. Moskvitin (SAO RAS), O. I. Spiridonova (SAO RAS), Yu. V. Sotnikova (SAO RAS), A. Ghosh (CAPP, University of Johannesburg), S. Razzaque (CAPP, University of Johannesburg) and IKI GRB-FuN report We observed the field of GRB 250329A (Wang et al., GCN 39916; Dichiara et al., GCN 39924) in the R filter with the 0.7-meter AS-32 telescope of the Abastumani Observatory (AbAO), in the R filter with the 1.5-meter AZT-33IK telescope of the Sayan Solar Observatory (Mondy) and in the Rc filter with the 1-meter Zeiss-1000 of SAO RAS. We do not detect the OT (Watson et al., GCN 39915; Wang et al., GCN 39917; Schneider et al., GCN 39918; Ghosh et al., GCN 39922; Ferro et al., GCN 39927) down to the following limits. Date UT start t-T0 Filter Exp. UL(3sigma) Telescope (mid, d) (s) 2025-03-29 17:07:10 0.56824 R 98 x 60 21.7 AS-32 2025-03-29 19:11:57 0.64726 R 38 x 120 22.7 AZT-33IK 2025-03-29 20:00:02 0.66837 Rc 7 x 300 22.3 Zeiss-1000 Photometry is based on nearby USNO-B1.0 stars and is not corrected for Galactic extinction RA Dec R2 197.4269 9.4669 15.26 197.4732 9.4981 13.49 197.4408 9.5091 15.64 View this GCN Circular online at https://gcn.nasa.gov/circulars/39985. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38003] Fermi trigger No 765078057: Global MASTER-Net observations report
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39984 SUBJECT: Fermi trigger No 765078057: Global MASTER-Net observations report DATE: 25/03/31 19:31:03 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB250331.07 (trigger No 765078057,06h 45m 38.40s , -32d 23m 24.0s, R=9.26) errorbox 56780 sec after notice time and 62879 sec after trigger time at 2025-03-31 19:08:51 UT, with upper limit up to 19.3 mag. The observations began at zenith distance = 30 deg. The sun altitude is -32.9 deg. The galactic latitude b = -15 deg., longitude l = 242 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2828891 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 62909 | 2025-03-31 19:08:51 | MASTER-SAAO | (06h 42m 35.05s , -35d 00m 33.0s) | C | 60 | 19.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39984. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38002] GRB 250329B: CAHA 2.2m telescope optical limit
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39983 SUBJECT: GRB 250329B: CAHA 2.2m telescope optical limit DATE: 25/03/31 18:52:11 GMT FROM: Youdong HU at INAF-OAB <huyoudong072(a)hotmail.com> A. J. Castro-Tirado, E. Fernandez-Garcia, I. Perez-Garcia, S.-Y. Wu, M. D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy (IAA-CSIC), Y.-D. Hu (GXU), and A. Fernandez-Martin, J. F. Agui Fernandez (CAHA) on behalf of a larger collaboration, report: Following the detection of GRB 250329B by SVOM/ECLAIRs (Xie et al. GCNC 39925), we triggered the 2.2m CAHA telescope (+ CAFOS) at the Calar Alto Observatory (Almeria, Spain). Images were gathered starting on Mar. 30 01:33:35 UT (i.e. ~13.4 hours after trigger) in Sloan-riz and clear bands for the error region. On the co-added z band image (90 x 10 s), no optical transient detected, includeing the afterglow detected by Swift/XRT (Beardmore et al. GCNC 39939, P. Evans GCNC 39971), which down to 22.5 mag. This non-detection is consistent with the reports from GWAC-F50A (Xin et al. GCNC 39926), Mephisto (Chen et al. GCNC 39929), SVOM/VT (Xin et al. GCNC 39931), SVOM/C-GFT (Wu et al. GCNC 39935), SVOM/F-GFT (Rakotondrainibe et al. GCNC 39945). We thank the staff at Calar Alto observatory for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/39983. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38001] GRB 250331D: Swift ToO observations
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39982 SUBJECT: GRB 250331D: Swift ToO observations DATE: 25/03/31 18:37:26 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a ToO observation of the Swift/BAT-detected event GRB 250331D. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021825 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the Swift/BAT event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/39982. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38000] Swift GRB 250331C: Global MASTER-Net observations report
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39981 SUBJECT: Swift GRB 250331C: Global MASTER-Net observations report DATE: 25/03/31 18:16:57 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB 250331C ( S. B. Cenko et al., GCN 39959) errorbox 48174 sec after notice time and 48531 sec after trigger time at 2025-03-31 18:06:32 UT, with upper limit up to 18.0 mag. The observations began at zenith distance = 75 deg. The sun altitude is -20.0 deg. The galactic latitude b = -1 deg., longitude l = 174 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2828956 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 48622 | MASTER-SAAO | C | 180 | 17.9 | 48821 | MASTER-SAAO | C | 180 | 18.0 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39981. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37999] Swift GRB 250331B: Global MASTER-Net observations report
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39980 SUBJECT: Swift GRB 250331B: Global MASTER-Net observations report DATE: 25/03/31 17:47:41 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB 250331B ( S. B. Cenko et al., GCN 39958) errorbox 47556 sec after notice time and 47612 sec after trigger time at 2025-03-31 17:33:15 UT, with upper limit up to 16.9 mag. Observations started at twilight. The observations began at zenith distance = 85 deg. The sun altitude is -13.0 deg. The galactic latitude b = -1 deg., longitude l = 161 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2828939 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 47702 | MASTER-SAAO | C | 180 | 16.5 | 47902 | MASTER-SAAO | C | 180 | 16.7 | 48101 | MASTER-SAAO | C | 180 | 16.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39980. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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