GRB250312A

This page lists all entries on GRB250312A in GRBweb

Summary Swift GCN 39686 GCN 39689 GCN 39693 GCN 39697 GCN 39765 GCN 39829

Summary table
Variable Value Source
T0 13:24:17 UTC GCN_circulars,Swift Det
ra 29.5191° Swift
decl -42.3960° Swift
pos_error 2.46e-04° Swift
GBM_located False
mjd 60746.558530092596 GCN_circulars,Swift Det
Swift table
GRB_name GRB250312A
t_trigger 13:24:17 UTC
ra 29.5191°
decl -42.3960°
pos_error 2.46e-04°
GCN 39686 table
GRB_name GRB250312A
GCN_number 39686
Detection_method Swift Det
t_trigger 13:24:17 UTC
ra 29.5100°
decl -42.4040°
Circular_text TITLE: GCN CIRCULAR NUMBER: 39686 SUBJECT: GRB 250312A: Swift detection of a burst DATE: 25/03/12 13:41:19 GMT FROM: K.L. Page at U Leicester A. Melandri (INAF-OAR), V. D'Elia (SSDC & INAF-OAR), J. J. DeLaunay (PSU), S. Dichiara (PSU), R. Gupta (NASA GSFC), J. A. Kennea (PSU), M. J. Moss (GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB) and M. A. Williams (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 13:24:17 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 250312A (trigger=1294765). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 29.510, -42.404 which is RA(J2000) = 01h 58m 02s Dec(J2000) = -42d 24' 15" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Only the first 8 seconds of the BAT light curve are immediately available. This limited data shows a complex peak structure that extends beyond the T+8s cut-off. The peak count rate was ~1800 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 13:26:33.0 UT, 135.4 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source with an enhanced position: RA, Dec 29.51911, -42.39599 which is equivalent to: RA(J2000) = 01h 58m 04.59s Dec(J2000) = -42d 23' 45.6" with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 37 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 in excess of the Galactic value (1.79 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3 (+2.65/-2.31) x 10^21 cm^-2 (90% confidence). The initial flux in the 2.5 s image was 7.29e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 427 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 expected extinction corresponding to E(B-V) of 0.017. Burst Advocate for this burst is A. Melandri (andrea.melandri AT inaf.it). 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/)
GCN 39689 table
GRB_name GRB250312A
GCN_number 39689
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 39689 SUBJECT: Swift GRB 250312A: Global MASTER-Net observations report DATE: 25/03/12 18:04:11 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs 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 250312A ( A. Melandri et al., GCN 39686) errorbox 15966 sec after notice time and 16003 sec after trigger time at 2025-03-12 17:51:00 UT, with upper limit up to 18.2 mag. Observations started at twilight. The observations began at zenith distance = 54 deg. The sun altitude is -11.5 deg. The galactic latitude b = -69 deg., longitude l = 264 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2809737 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 16093 | MASTER-SAAO | C | 180 | 17.1 | 16292 | MASTER-SAAO | C | 180 | 18.2 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
GCN 39693 table
GRB_name GRB250312A
GCN_number 39693
Detection_method Swift-XRT Det
ra 29.5195°
decl -42.3961°
Circular_text TITLE: GCN CIRCULAR NUMBER: 39693 SUBJECT: GRB 250312A: Enhanced Swift-XRT position DATE: 25/03/12 22:04:03 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 1241 s of XRT Photon Counting mode data and 2 UVOT images for GRB 250312A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 29.51954, -42.39605 which is equivalent to: RA (J2000): 01h 58m 4.69s Dec (J2000): -42d 23' 45.8" with an uncertainty of 2.4 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN 39697 table
GRB_name GRB250312A
GCN_number 39697
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 39697 SUBJECT: GRB 250312A: Swift-XRT refined Analysis DATE: 25/03/13 01:21:03 GMT FROM: Phil Evans at U of Leicester D.N. Burrows (PSU), M. A. Williams (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), S. Dichiara (PSU) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 8.3 ks of XRT data for GRB 250312A, from 385 s to 34.7 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The light curve can be modelled with a power-law decay with a decay index of alpha=0.51 (+/-0.06). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.80 (+0.22, -0.21). The best-fitting absorption column is 1.3 (+0.7, -0.6) x 10^21 cm^-2, in excess of the Galactic value of 1.8 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.9 x 10^-11 (4.7 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.3 (+0.7, -0.6) x 10^21 cm^-2 Galactic foreground: 1.8 x 10^20 cm^-2 Excess significance: 3.0 sigma Photon index: 1.80 (+0.22, -0.21) If the light curve continues to decay with a power-law decay index of 0.51, the count rate at T+24 hours will be 0.022 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.5 x 10^-13 (1.0 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01294765. This circular is an official product of the Swift-XRT team.
GCN 39765 table
GRB_name GRB250312A
GCN_number 39765
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 39765 SUBJECT: GRB250312A: Swift/UVOT Upper Limits DATE: 25/03/17 20:21:01 GMT FROM: Mike Siegel at PSU/Swift MOC M. H.Siegel (PSU) and A. Melandri (INAF-OAR) on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 250312A 464s after the BAT trigger (Melandri et al., GCN Circ. 39686). No optical afterglow consistent with the enhanced XRT position (Evans et al., GCN Circ. 39693) is detected in the initial UVOT exposures.Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white (fc) 464 1563 165 >20.47 white 743 1563 223 >20.50 b 718 1539 38 >18.84 b 6529 33943 1081 >20.52 u 6324 23538 403 >19.80 uvw1 21814 22713 885 >19.99 uvm2 10515 16904 1012 >19.85 uvw2 6939 28312 1082 >20.24 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.015 in the direction of the burst (Schlegel et al. 1998).
GCN 39829 table
GRB_name GRB250312A
GCN_number 39829
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 39829 SUBJECT: GRB 250312A: GECAM-A detection DATE: 25/03/22 05:44:25 GMT FROM: zhengchao_astro@foxmail.com Jia-Cong Liu, Shao-Lin Xiong, Peng Zhang, Yan-Qiu Zhang, Chen-Wei Wang (IHEP) report on behalf of the GECAM team: GECAM-A detected a long burst, GRB 250312A, at 2025-03-12T13:24:17 UTC (denoted as T0), which was also observed by Swift/BAT (A. Melandri et al. 2025, GCN 39686). According to the GECAM-A light curves in about 50-200 keV, this burst mainly consists of a pulse with a T90 of about 5.0 ± 0.2 s. The GECAM light curve can be found here: https://www.bursthub.cn//admin/static/gecamgrb250312A.png We note that these results are preliminary. Refined analysis will be reported.  Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two microsatellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).