GRB250226B

This page lists all entries on GRB250226B in GRBweb

Summary Fermi GBM GCN 39503 GCN 39505 GCN 39519 GCN 39673 GCN 39690

Summary table
Variable Value Source
GRB_name_Fermi GRB250226938
T0 22:30:23 UTC GCN_circulars,Fermi GBM final loc
ra 284.4200° Fermi_GBM
decl -10.8200° Fermi_GBM
pos_error 2.82e+00° Fermi_GBM
T90 25.857 s Fermi_GBM
T90_error 1.056 s Fermi_GBM
T90_start 22:30:23.699 UTC Fermi_GBM
fluence 8.99e-06 erg/cm² Fermi_GBM
fluence_error 3.45e-08 erg/cm² Fermi_GBM
T100 26.556 s
GBM_located True
mjd 60732.9377662037 GCN_circulars,Fermi GBM final loc
Fermi GBM table
GRB_name_Fermi GRB250226938
trigger_name bn250226938
ra 284.4200°
decl -10.8200°
pos_error 2.82e+00°
datum 2025-02-26
t_trigger 22:30:23.123 UTC
T90 25.857 s
T90_error 1.056 s
T90_start 22:30:23.699 UTC
fluence 8.99e-06 erg/cm²
fluence_error 3.45e-08 erg/cm²
flux_1024 9.70e+00 erg/cm²/s
flux_1024_error 2.49e-01 erg/cm²/s
flux_1024_time 1.73e+00 erg/cm²/s
flux_64 1.55e+01 erg/cm²/s
flux_64_error 1.09e+00 erg/cm²/s
GCN 39503 table
GRB_name GRB250226B
GCN_number 39503
Detection_method Fermi GBM final loc
t_trigger 22:30:23 UTC
ra 284.4000°
decl -10.8000°
Circular_text TITLE: GCN CIRCULAR NUMBER: 39503 SUBJECT: GRB 250226B: Fermi GBM Final Real-time Localization DATE: 25/02/26 22:40:51 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 22:30:23 UT on 26 Feb 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250226B (trigger 762301828.12293 / 250226938). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 284.4, Dec = -10.8 (J2000 degrees, equivalent to J2000 18h 57m, -10d 48'), with a statistical uncertainty of 1.9 degrees. The angle from the Fermi LAT boresight is 71.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250226938/quicklook/glg_skymap_all_bn250226938.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/bn250226938/quicklook/glg_healpix_all_bn250226938.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250226938/quicklook/glg_lc_medres34_bn250226938.gif
GCN 39505 table
GRB_name GRB250226B
GCN_number 39505
Detection_method Fermi GBM Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 39505 SUBJECT: Fermi GRB 250226B: Global MASTER-Net observations report DATE: 25/02/26 23:31:13 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-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 250226B ( Fermi GBM team, GCN 39503) errorbox 99 sec after notice time and 134 sec after trigger time at 2025-02-26 22:32:37 UT, with upper limit up to 16.4 mag. Observations started at twilight. The observations began at zenith distance = 75 deg. The sun altitude is -13.9 deg. The galactic latitude b = -7 deg., longitude l = 24 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2792989 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 150 | 2025-02-26 22:32:37 | MASTER-Tunka | (18h 59m 50.08s , -12d 13m 54.5s) | C | 30 | 16.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
GCN 39519 table
GRB_name GRB250226B
GCN_number 39519
Detection_method INTEGRAL
Circular_text TITLE: GCN CIRCULAR NUMBER: 39519 SUBJECT: GRB 250226B: INTEGRAL SPI-ACS and PICsIT detection DATE: 25/02/27 14:32:17 GMT FROM: Aishwarya L Thakur at INAF-IAPS, Rome James Craig Rodi(a), Aishwarya Linesh Thakur(a), Patrizia Barria(a,b), Giulia Gianfagna(a), Lorenzo Natalucci(a,b), Luigi Piro(a), report: GRB 250226B was discovered by Fermi/GBM (GCN 39503) at 2025-02-26T22:30:23 (UTC). In a SPI-ACS light curve above 80 keV, we find a signal temporally coincident with the GBM detection, having an approximate duration of ~ 20 sec. The signal consists of multiple pulses over this duration. The strongest pulse of this signal is also detected in the IBIS/PICsIT data. The approximate peak count rate in SPI-ACS is 95,000 cts/s for E>80 keV, over a median background rate of 63,000 cts/s. This work is based on observations with INTEGRAL, an ESA project with instruments and a science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, and Spain), and with the participation of Russia and the USA. The SPI-ACS detector system has been provided by MPE Garching/Germany. ----- (a) INAF/IAPS-Rome (b) ICSC National Research Centre for High-Performance Computing
GCN 39673 table
GRB_name GRB250226B
GCN_number 39673
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 39673 SUBJECT: GRB 250226B: Swift/BAT-GUANO localization skymap of a likely long GRB DATE: 25/03/11 20:10:47 GMT FROM: Samuele Ronchini at PSU Samuele Ronchini (PSU), James DeLaunay (PSU), Aaron Tohuvavohu (Caltech), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT did not localize GRB 250226B onboard (T0: 2025-02-26T22:30:23.12 UTC, Fermi GCN 39503, INTEGRAL GCN 39519) The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 15.1 in a 1.024 s analysis time bin, starting at T0 + 1.79 s. Using the NITRATES analysis, parameter estimation was performed to obtain the localization of this burst in the form of a HEALPIX Multi-Order Coverage (MOC) skymap. This localization accounts for both statistical and systematic errors. More details in the creation and calibration of these maps will soon be published (DeLaunay et al. 2025. in prep) The 90% credible area is 3,416 deg2 and the 50% credible area is 994 deg2. The integrated probability inside the coded field of view is 6%. The joint NITRATES+GBM localization has a 90% credible area of 165 deg2 and a 50% credible area of 36 deg2 A plot of the probability skymap can be viewed here: [skymap_plot](https://guano.swift.psu.edu/trigger_report?id=762301858/#:~:text=Probability%20Skymap) The probability skymap and joint skymap files can be downloaded from the links here [skymap_fits_file](https://guano.swift.psu.edu/files/762301858/0_n_PROBMAP) [joint_skymap_fits_file](https://guano.swift.psu.edu/files/762301858/0_n_JOINTMAP) Instructions on how to read and manipulate this map can be found here: https://guano.swift.psu.edu/documentation More details about this burst can be found on the trigger report page here: https://guano.swift.psu.edu/trigger_report?id=762301858 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
GCN 39690 table
GRB_name GRB250226B
GCN_number 39690
Detection_method Fermi GBM Det
t_trigger 22:30:23.120 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 39690 SUBJECT: GRB 250226B: Fermi GBM Observation DATE: 25/03/12 20:16:32 GMT FROM: Jacob Smith at Fermi-GBM Team Jacob Smith (UAH) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: At 22:30:23.12 UT on 26 February 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250226B (trigger 762301828/250226938). which was also detected by INTEGRAL SPI-ACS (J. Rodi, et al. 2025, GCN 39519) and Swift/BAT-GUANO (S. Ronchini, et al., 2025, GCN 39673). The angle from the Fermi LAT boresight is 71 degrees. The GBM light curve consists of multiple peaks with a duration (T90) of about 26 s (50-300 keV). The time-averaged spectrum from T0+0.003 to T0+27.457 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.09 +/- 0.03 and the cutoff energy, parameterized as Epeak, is 1688 +/- 250 keV. The event fluence (10-1000 keV) in this time interval is (1.60 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.7 s in the 10-1000 keV band is 9.7 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/