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This page lists all entries on GRB250404B in GRBweb

Summary GCN 40078 GCN 40630

Summary table
Variable	Value	Source
T0	18:36:10 UTC	GCN_circulars,IPN Triangulation
ra	273.6290°	GCN_circulars,IPN Triangulation
decl	-2.2510°	GCN_circulars,IPN Triangulation
GBM_located	False
mjd	60769.77511574074	GCN_circulars,IPN Triangulation

GCN 40078 table
GRB_name	GRB250404B
GCN_number	40078
Detection_method	AstroSat CZTI
Circular_text	TITLE: GCN CIRCULAR NUMBER: 40078 SUBJECT: GRB 250404B: AstroSat CZTI detection of a short burst DATE: 25/04/05 10:39:48 GMT FROM: Gaurav Waratkar at IIT Bombay S. Salunke (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a short duration GRB 250404B. The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2025-04-04 18:36:09.15 UTC. The measured peak count rate associated with the burst is 720 (+181, -101) counts/s above the background in the combined data of three quadrants (out of four), with a total of 375 (+52, -54) counts. The local mean background count rate was 292 (+10, -13) counts/s. Using cumulative rates, we measure a T90 of 0.79 (+0.04, -0.05) s. The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaked at 2025-04-04 18:36:08.40 UTC. The measured peak count rate associated with the burst is 665 (+73, -81) counts/s above the background in the combined data of all quadrants, with a total of 635 (+154, -167) counts. The local mean background count rate was 1266 (+14, -15) counts/s. Due to the intrinsic 1 s binning of veto data, we cannot reliably estimate a T90 from it. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=grb

GCN 40630 table
GRB_name	GRB250404B
GCN_number	40630
Detection_method	IPN Triangulation
t_trigger	18:36:10 UTC
ra	273.6290°
decl	-2.2510°
Circular_text	TITLE: GCN CIRCULAR NUMBER: 40630 SUBJECT: IPN triangulation of GRB 250404B DATE: 25/06/05 15:32:58 GMT FROM: Anna Ridnaia at Ioffe Institute A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars Odyssey team, D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, E. Burns on behalf of the IPN, S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, A. Tohuvavohu, and J. DeLaunay on behalf of the Swift-BAT team, G. Waratkar, J.Joshi, V. Bhalerao, D. Bhattacharya, and S. Vadawale, on behalf of the Astrosat-CZTI team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report: The short-duration GRB 250404B (AstroSat CZTI detection: Salunke et al., GCN Circ. 40078) was detected by Konus-Wind, Swift (BAT), AstroSat (CZTI), and Mars-Odyssey (HEND) at about 66970 s UT (18:36:10). The burst was outside the coded field of view of the BAT. We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 273.629 (18h 14m 31s) -2.251 ( -2d 15' 03") Corners: 273.108 (18h 12m 26s) -2.676 ( -2d 40' 35") 274.127 (18h 16m 31s) -1.659 ( -1d 39' 32") 274.151 (18h 16m 36s) -1.842 ( -1d 50' 30") 273.131 (18h 12m 31s) -2.866 ( -2d 51' 58") --------------------------------------------- The error box area is 768 sq. arcmin, and its maximum dimension is 1.6 deg (the minimum one is 9 arcmin). The Sun distance was 100 deg. This localization may be improved. A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB250404_T66970/IPN/ The HEALPix triangulation map is the multi-order HEALPix in units of probability density. The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.