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

[vsnet-grb-info 37978] GRB 250331C: Swift detection of a burst
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39959 SUBJECT: GRB 250331C: Swift detection of a burst DATE: 25/03/31 04:55:40 GMT FROM: David Palmer at LANL <palmer(a)lanl.gov> S. B. Cenko (GSFC), C. Gronwall (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 04:37:40 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 250331C (trigger=1299967). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 80.993, +33.029 which is RA(J2000) = 05h 23m 58s Dec(J2000) = +33d 01' 43" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 25 sec. The peak count rate was ~800 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 04:39:51.5 UT, 130.9 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 80.95740, 33.06310 which is equivalent to: RA(J2000) = 05h 23m 49.78s Dec(J2000) = +33d 03' 47.2" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 163 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 6.49 x 10^21 cm^-2 (Willingale et al. 2013). The initial flux in the 2.5 s image was 1.04e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 139 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain, extinction expected. Burst Advocate for this burst is S. B. Cenko (brad.cenko AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) View this GCN Circular online at https://gcn.nasa.gov/circulars/39959. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37977] GRB 250331B: Swift detection of a burst
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39958 SUBJECT: GRB 250331B: Swift detection of a burst DATE: 25/03/31 04:47:31 GMT FROM: David Palmer at LANL <palmer(a)lanl.gov> S. B. Cenko (GSFC), C. Gronwall (PSU), R. Gupta (NASA GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 04:19:43 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 250331B (trigger=1299965). Swift slewed to the burst after a brief delay to clear an observing constraint. The BAT on-board calculated location is RA, Dec 71.381, +43.805 which is RA(J2000) = 04h 45m 31s Dec(J2000) = +43d 48' 17" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peak structure with a duration of about 8 sec. The peak count rate was ~1400 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began observing the field at 04:24:57.3 UT, 313.9 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 71.37364, 43.81080 which is equivalent to: RA(J2000) = 04h 45m 29.67s Dec(J2000) = +43d 48' 38.9" with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 28 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time. A power-law fit to a spectrum formed from promptly downlinked event data does not constrain the column density. UVOT took a finding chart exposure of 150 seconds with the White filter starting 317 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain, extinction expected. Burst Advocate for this burst is S. B. Cenko (brad.cenko AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) View this GCN Circular online at https://gcn.nasa.gov/circulars/39958. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37976] GRB 250330A: SVOM/VT optical upper limit
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39957 SUBJECT: GRB 250330A: SVOM/VT optical upper limit DATE: 25/03/31 04:35:08 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Z.M. Wang, A. Li (BNU), L.P. Xin, H.L. Li, Y. L. Qiu, C. Wu, Z.H. Yao, Y. Xu, P.P. Zhang, J. Wang, Y.N. Ma, X.H. Han, H.B. Cai, J.Y. Wei(NAOC) report on behalf of the SVOM/VT team: SVOM performed two Target of Opportunity observations of GRB 250330A (Cenko et al., GCN 39938; Pathak, GCN 39944; Osborne et al., GCN 39947) in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously， starting at 2025-03-30T09:17:44 UT, and 2025-03-30T12:40:58 UT, respectively. No sources were detected in the stacked images within the XRT source position (Page, GCN 39940). The 3 sigma limits in VT_R is 21.7 mag (AB) with the exposure time of 3 x 100s at the medium time of 3.2 hours after the Swift BAT trigger, and 23.0 mag with the exposure of 12*120s, at the medium time of 6.8 hours after the burst. This result is consistent with the reports (Becerra, GCN 39941; Siegel et al., GCN 39948; Perez-Garcia et al., GCN 39949; Lipunov et al., GCN 39950). The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC),CAS. View this GCN Circular online at https://gcn.nasa.gov/circulars/39957. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37975] GRB 250331A: MAXI/GSC detection
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39956 SUBJECT: GRB 250331A: MAXI/GSC detection DATE: 25/03/31 03:44:29 GMT FROM: Yuta Kawakubo at Aoyama Gakuin University <kawakubo(a)phys.aoyama.ac.jp> K. Takagi, M. Nakajima (Nihon U.), Y. Kawakubo, M. Serino (AGU), H. Negoro, Y. Kudo, H. Shibui, H. Takahashi, K. Tatano, H. Nishio (Nihon U.), T. Mihara, S. Yamada, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, H. Hiramatsu, H. Nishikawa, Y. Kondo, S. Sasao, A. Yoshida (AGU), Y. Tsuboi, H. Sugai, N. Nagashima (Chuo U.), M. Shidatsu, Y. Niida, C. Kang, T. Nakamoto (Ehime U.), I. Takahashi, M. Niwano, N. Higuchi, Y. Yatsu (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, M. Kurihara (JAXA), Y. Ueda, Y. Okada, K. Fujiwara (Kyoto U.), M. Yamauchi, Y. Otsuki, T. Hasegawa, M. Nishio (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Sugizaki (Kanazawa U.), W. Iwakiri (Chiba U.), T. Kawamuro (Osaka U.) report on behalf of the MAXI team: The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 01:40:54 UT on March 31, 2025. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (124.987 deg, -18.636 deg) = (08 19 56, -18 38 09) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.25 deg and 0.2 deg, respectively. The roll angle of long axis from the north direction is 168.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 146 +- 23 mCrab (4.0-10.0keV, 1 sigma error). Without assumptions on the source constancy, we obtain a rectangular error box for the transient source with the following corners: (124.498, -17.690) deg = (08 17 59, -17 41 24) (J2000) (124.178, -17.935) deg = (08 16 42, -17 56 05) (J2000) (125.521, -19.513) deg = (08 22 05, -19 30 46) (J2000) (125.843, -19.266) deg = (08 23 22, -19 15 57) (J2000) There was no significant excess flux in the previous transit at 0:08 UT and in the next transit at 03:14 UT with an upper limit of 20 mCrab for each. View this GCN Circular online at https://gcn.nasa.gov/circulars/39956. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37974] SVOM/sb25033102: SVOM detection of an X-ray transient
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39955 SUBJECT: SVOM/sb25033102: SVOM detection of an X-ray transient DATE: 25/03/31 03:40:23 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Yinuo MA, Chao WU, Donghua ZHAO, Wenjin XIE (NAOC), Hatsune GOTO (CEA, Kanazawa Univ) on behalf of the SVOM mission team. At 2025-03-31T02:04:18 UTC (Tb) SVOM/ECLAIRs triggered on the X-ray transient labelled sb25033102 (SVOM burst-id sb25033102). The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network. This transient was only detected by the Count-Rate Trigger (CRT), which produced a sequence of 1 alerts. CRT provided the alert with the best signal-to-noise-ratio (SNR) of 15.10 in the [8-120] keV energy band over a time window of 20.48 seconds starting at Tb. The localization of the best alert is R.A., Dec 289.235, -18.527 degrees: RA (J2000) = 19h16m56.51s Dec (J2000) = -18d31m37.10s with a 90% C.L. radius of 5.48 arcmin (including systematic error of 2 arcmin added in quadrature). We notice that this transient also triggered SVOM/ECLAIRs at the 1.57 hours before, at 2025-03-31T00:29:51.04 (SVOM/sb25033101). Due to an external ToO was performing by SVOM, no immediate slew was performed on this transient. The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. The Burst Advocate (BA) on shift for this burst is Yinuo MA: mayn(a)bao.ac.cn Please contact the BA by email if you require additional information regarding the SVOM follow-up of this burst. View this GCN Circular online at https://gcn.nasa.gov/circulars/39955. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37973] GRB 250314A: VLA detection
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39954 SUBJECT: GRB 250314A: VLA detection DATE: 25/03/31 02:49:59 GMT FROM: Tanmoy Laskar at U of Utah <tanmoylaskar(a)gmail.com> Nayana A. J. (UC Berkeley), T. Laskar (University of Utah), R. Margutti (UC Berkeley), K. D. Alexander (University of Arizona), R. Chornock (UC Berkeley), E. Berger (Harvard University), W. Fong (Northwestern University), P. Schady (University of Bath), and G. Schroeder (Cornell University) report: "We carried out Karl G. Jansky Very Large Array (VLA) observations of the high-redshift (z ~ 7.3; Malesani et al., GCN 39732; Rakotondrainibe et al., GCN 39743) SVOM/ECLAIRs GRB 250314A (Wang et al., GCN 39719) beginning on 2025 March 21 06:26 UTC (6.7 days after the burst) at multiple frequencies. In preliminary analysis, we detect a radio counterpart with a flux density of ~ 0.1 mJy at 17 GHz, and position: RA (J2000) = 13:25:12.16 Dec (J2000) = -05:16:55.07 with a (statistical) uncertainty of 0.6" in each coordinate. This position is consistent with the optical position (Malesani et al., GCN 39727). Further observations are planned. We thank the VLA staff for scheduling and executing these observations" View this GCN Circular online at https://gcn.nasa.gov/circulars/39954. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37972] LIGO/Virgo/KAGRA S250331o: Identification of a GW compact binary merger candidate
by GCN Circulars 31 Mar '25

31 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39953 SUBJECT: LIGO/Virgo/KAGRA S250331o: Identification of a GW compact binary merger candidate DATE: 25/03/31 02:06:54 GMT FROM: Gyoik Kim at Yonsei University <gyoik_kim(a)yonsei.ac.kr> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S250331o during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2025-03-31 01:34:48.438 UTC (GPS time: 1427420106.438). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], PyCBC Live [4], and SPIIR [5] analysis pipelines. S250331o is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S250331o After parameter estimation by RapidPE-RIFT [6], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that at least one of the compact objects is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 23 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is well fit by an ellipse with an area of 27 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, +31d24m, 4.57d, 1.87d, 116.86d) Marginalized over the whole sky, the a posteriori luminosity distance estimate is 582 +/- 120 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] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. PRD 109, 042008 (2024) doi:10.1103/PhysRevD.109.042008 [4] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [5] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [6] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/39953. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37971] Fermi GRB 250330B: Global MASTER-Net observations report
by GCN Circulars 30 Mar '25

30 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39952 SUBJECT: Fermi GRB 250330B: Global MASTER-Net observations report DATE: 25/03/30 23:15:59 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 GRB 250330B ( Fermi GBM team, GCN 39951) errorbox 54 sec after notice time and 92 sec after trigger time at 2025-03-30 21:53:54 UT, with upper limit up to 17.4 mag. The observations began at zenith distance = 77 deg. The sun altitude is -59.7 deg. The galactic latitude b = 16 deg., longitude l = 206 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2828695 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 102 | 2025-03-30 21:53:54 | MASTER-SAAO | (07h 22m 19.10s , +12d 01m 03.3s) | C | 20 | 17.1 | 141 | 2025-03-30 21:54:33 | MASTER-SAAO | (07h 22m 19.82s , +12d 01m 05.9s) | C | 20 | 17.0 | 186 | 2025-03-30 21:55:12 | MASTER-SAAO | (07h 22m 20.65s , +12d 01m 08.5s) | C | 30 | 17.1 | 240 | 2025-03-30 21:56:01 | MASTER-SAAO | (07h 22m 21.73s , +12d 01m 11.2s) | C | 40 | 17.0 | 304 | 2025-03-30 21:57:00 | MASTER-SAAO | (07h 22m 23.03s , +12d 01m 14.3s) | C | 50 | 16.9 | 378 | 2025-03-30 21:58:10 | MASTER-SAAO | (07h 22m 24.54s , +12d 01m 18.1s) | C | 60 | 16.9 | 629 | 2025-03-30 22:02:21 | MASTER-SAAO | (07h 36m 00.30s , +13d 19m 14.0s) | C | 60 | 17.4 | 709 | 2025-03-30 22:03:40 | MASTER-SAAO | (07h 36m 01.77s , +13d 19m 17.5s) | C | 60 | 17.4 | 788 | 2025-03-30 22:04:59 | MASTER-SAAO | (07h 36m 03.30s , +13d 19m 20.6s) | C | 60 | 17.4 | 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/39952. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37970] GRB 250330B: Fermi GBM Final Real-time Localization
by GCN Circulars 30 Mar '25

30 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39951 SUBJECT: GRB 250330B: Fermi GBM Final Real-time Localization DATE: 25/03/30 22:03:10 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 SHORT GRB At 21:52:22 UT on 30 Mar 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250330B (trigger 765064347.102666 / 250330911). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 114.1, Dec = 13.3 (J2000 degrees, equivalent to J2000 07h 36m, 13d 18'), with a statistical uncertainty of 3.1 degrees. The angle from the Fermi LAT boresight is 81.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250330911/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250330911/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250330911/… View this GCN Circular online at https://gcn.nasa.gov/circulars/39951. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37969] Fermi GRB 250330A: Global MASTER-Net observations report
by GCN Circulars 30 Mar '25

30 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39950 SUBJECT: Fermi GRB 250330A: Global MASTER-Net observations report DATE: 25/03/30 19:16:02 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 GRB 250330A ( Fermi GBM team, GCN 39944) errorbox 41642 sec after notice time and 41678 sec after trigger time at 2025-03-30 17:42:16 UT, with upper limit up to 18.5 mag. Observations started at twilight. The observations began at zenith distance = 69 deg. The sun altitude is -14.6 deg. The galactic latitude b = -16 deg., longitude l = 316 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2828018 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 41709 | 2025-03-30 17:42:16 | MASTER-SAAO | (16h 01m 09.95s , -72d 45m 24.7s) | C | 60 | 18.1 | 41788 | 2025-03-30 17:43:36 | MASTER-SAAO | (16h 28m 26.03s , -72d 45m 15.7s) | C | 60 | 18.2 | 41868 | 2025-03-30 17:44:56 | MASTER-SAAO | (16h 02m 18.38s , -74d 39m 19.9s) | C | 60 | 18.0 | 41947 | 2025-03-30 17:46:15 | MASTER-SAAO | (16h 32m 49.13s , -74d 37m 47.3s) | C | 60 | 18.3 | 42026 | 2025-03-30 17:47:34 | MASTER-SAAO | (15h 04m 24.83s , -74d 37m 14.9s) | C | 60 | 18.4 | 42106 | 2025-03-30 17:48:54 | MASTER-SAAO | (15h 34m 57.62s , -74d 38m 25.7s) | C | 60 | 18.4 | 42186 | 2025-03-30 17:50:14 | MASTER-SAAO | (15h 09m 38.19s , -72d 45m 00.7s) | C | 60 | 18.2 | 42265 | 2025-03-30 17:51:33 | MASTER-SAAO | (15h 36m 45.01s , -72d 44m 01.7s) | C | 60 | 18.3 | 42345 | 2025-03-30 17:52:52 | MASTER-SAAO | (16h 01m 11.29s , -72d 45m 24.8s) | C | 60 | 18.2 | 42424 | 2025-03-30 17:54:12 | MASTER-SAAO | (16h 28m 23.83s , -72d 44m 12.1s) | C | 60 | 18.2 | 42866 | 2025-03-30 18:01:34 | MASTER-SAAO | (16h 02m 13.55s , -74d 39m 54.2s) | C | 60 | 17.9 | 42945 | 2025-03-30 18:02:53 | MASTER-SAAO | (16h 32m 48.33s , -74d 40m 05.2s) | C | 60 | 18.3 | 43025 | 2025-03-30 18:04:13 | MASTER-SAAO | (15h 04m 23.51s , -74d 37m 45.9s) | C | 60 | 18.4 | 43104 | 2025-03-30 18:05:32 | MASTER-SAAO | (15h 34m 50.67s , -74d 39m 22.5s) | C | 60 | 18.5 | 43184 | 2025-03-30 18:06:52 | MASTER-SAAO | (15h 09m 34.64s , -72d 44m 00.2s) | C | 60 | 18.2 | 43263 | 2025-03-30 18:08:11 | MASTER-SAAO | (15h 36m 38.09s , -72d 44m 59.8s) | C | 60 | 18.3 | 43343 | 2025-03-30 18:09:31 | MASTER-SAAO | (16h 01m 06.13s , -72d 44m 09.8s) | C | 60 | 18.2 | 45719 | 2025-03-30 18:49:07 | MASTER-SAAO | (16h 28m 13.93s , -72d 47m 17.6s) | C | 60 | 18.2 | 45798 | 2025-03-30 18:50:26 | MASTER-SAAO | (16h 02m 10.31s , -74d 39m 28.3s) | C | 60 | 18.1 | 45878 | 2025-03-30 18:51:46 | MASTER-SAAO | (16h 32m 34.04s , -74d 40m 31.3s) | C | 60 | 18.3 | 46778 | 2025-03-30 19:06:46 | MASTER-SAAO | (15h 04m 04.80s , -74d 39m 00.1s) | C | 60 | 18.5 | 46858 | 2025-03-30 19:08:05 | MASTER-SAAO | (15h 34m 34.17s , -74d 41m 15.3s) | C | 60 | 18.4 | 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/39950. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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