GRB250421A

This page lists all entries on GRB250421A in GRBweb

Summary Fermi GBM GCN 40191 GCN 40201 GCN 40214

Summary table
Variable Value Source
GRB_name_Fermi GRB250421443
T0 10:38:30.832 UTC Fermi_GBM
ra 249.0600° Fermi_GBM
decl -59.8600° Fermi_GBM
pos_error 3.92e+00° Fermi_GBM
T90 10.24 s Fermi_GBM
T90_error 0.923 s Fermi_GBM
T90_start 10:38:30.832 UTC Fermi_GBM
fluence 2.51e-06 erg/cm² Fermi_GBM
fluence_error 3.03e-08 erg/cm² Fermi_GBM
T100 10.24 s
GBM_located True
mjd 60786.44341240741 Fermi_GBM
Fermi GBM table
GRB_name_Fermi GRB250421443
trigger_name bn250421443
ra 249.0600°
decl -59.8600°
pos_error 3.92e+00°
datum 2025-04-21
t_trigger 10:38:31.344 UTC
T90 10.24 s
T90_error 0.923 s
T90_start 10:38:30.832 UTC
fluence 2.51e-06 erg/cm²
fluence_error 3.03e-08 erg/cm²
flux_1024 5.66e+00 erg/cm²/s
flux_1024_error 3.47e-01 erg/cm²/s
flux_1024_time 2.75e+00 erg/cm²/s
flux_64 8.08e+00 erg/cm²/s
flux_64_error 1.54e+00 erg/cm²/s
GCN 40191 table
GRB_name GRB250421A
GCN_number 40191
Detection_method Fermi GBM final loc
t_trigger 10:38:31 UTC
ra 249.1000°
decl -59.9000°
Circular_text TITLE: GCN CIRCULAR NUMBER: 40191 SUBJECT: GRB 250421A: Fermi GBM Final Real-time Localization DATE: 25/04/21 10:48:59 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 10:38:31 UT on 21 Apr 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250421A (trigger 766924716.344264 / 250421443). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 249.1, Dec = -59.9 (J2000 degrees, equivalent to J2000 16h 36m, -59d 53'), with a statistical uncertainty of 3.8 degrees. The angle from the Fermi LAT boresight is 103.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250421443/quicklook/glg_skymap_all_bn250421443.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250421443/quicklook/glg_healpix_all_bn250421443.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250421443/quicklook/glg_lc_medres34_bn250421443.gif
GCN 40201 table
GRB_name GRB250421A
GCN_number 40201
Detection_method Fermi GBM Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 40201 SUBJECT: Fermi GRB 250421A: Global MASTER-Net observations report DATE: 25/04/22 06:17:02 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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 250421A ( Fermi GBM team, GCN 40191) errorbox 67295 sec after notice time and 67337 sec after trigger time at 2025-04-22 05:20:48 UT, with upper limit up to 18.9 mag. The observations began at zenith distance = 33 deg. The sun altitude is -68.2 deg. The galactic latitude b = -9 deg., longitude l = 328 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2848837 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 67368 | 2025-04-22 05:20:48 | MASTER-OAFA | (16h 29m 49.10s , -59d 22m 10.8s) | C | 60 | 18.4 | 67601 | 2025-04-22 05:24:42 | MASTER-OAFA | (16h 25m 54.95s , -61d 15m 16.6s) | C | 60 | 18.4 | 67790 | 2025-04-22 05:28:01 | MASTER-OAFA | (16h 37m 54.84s , -62d 00m 16.5s) | C | 40 | 17.4 | 67800 | 2025-04-22 05:28:01 | MASTER-OAFA | (16h 57m 07.49s , -61d 33m 46.3s) | C | 60 | 18.9 | 68001 | 2025-04-22 05:31:22 | MASTER-OAFA | (16h 29m 45.37s , -59d 21m 53.7s) | C | 60 | 18.3 | 68194 | 2025-04-22 05:34:44 | MASTER-OAFA | (16h 41m 10.93s , -60d 04m 07.5s) | C | 40 | 17.2 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
GCN 40214 table
GRB_name GRB250421A
GCN_number 40214
Detection_method AstroSat CZTI
Circular_text TITLE: GCN CIRCULAR NUMBER: 40214 SUBJECT: GRB 250421A: AstroSat CZTI detection DATE: 25/04/23 06:55:12 GMT FROM: Varun Bhalerao at IIT Bombay M. Tembhurnikar (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 long-duration GRB 250421A which was also detected by Fermi/GBM (Fermi GBM Team, GCN Circ. 40191) and Konus-Wind (IPN Notices). The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2025-04-21 10:38:34.50 UTC. The measured peak count rate associated with the burst is 137 (+34, -32) counts/s above the background in the combined data of three quadrants (out of four), with a total of 294 (+129, -105) counts. The local mean background count rate was 230 (+3, -5) counts/s. Using cumulative rates, we measure a T90 of 5.6 (+1.7, -3.3) s. The source was also faintly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2025-04-21 10:38:34.17 UTC. The measured peak count rate associated with the burst is 261 (+67, -71) counts/s above the background in the combined data of all quadrants, with a total of 623 (+290, -324) counts. The local mean background count rate was 1349 (+10, -10) counts/s. We measure a T90 of 4.8 (+1.3, -3.1) s from the cumulative Veto light curve. 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