GRB250228A

This page lists all entries on GRB250228A in GRBweb

Summary Fermi GBM GCN 39547 GCN 39674 GCN 39680

Summary table
Variable Value Source
GRB_name_Fermi GRB250228308
T0 7:23:45.965 UTC Fermi_GBM
ra 94.9000° Fermi_GBM
decl -46.8100° Fermi_GBM
pos_error 8.54e+00° Fermi_GBM
T90 0.576 s Fermi_GBM
T90_error 0.375 s Fermi_GBM
T90_start 7:23:45.965 UTC Fermi_GBM
fluence 1.54e-07 erg/cm² Fermi_GBM
fluence_error 6.00e-09 erg/cm² Fermi_GBM
T100 0.576 s
GBM_located True
mjd 60734.30817089121 Fermi_GBM
Fermi GBM table
GRB_name_Fermi GRB250228308
trigger_name bn250228308
ra 94.9000°
decl -46.8100°
pos_error 8.54e+00°
datum 2025-02-28
t_trigger 7:23:46.157 UTC
T90 0.576 s
T90_error 0.375 s
T90_start 7:23:45.965 UTC
fluence 1.54e-07 erg/cm²
fluence_error 6.00e-09 erg/cm²
flux_1024 4.85e-01 erg/cm²/s
flux_1024_error 1.88e-01 erg/cm²/s
flux_1024_time 1.28e-01 erg/cm²/s
flux_64 2.38e+00 erg/cm²/s
flux_64_error 8.27e-01 erg/cm²/s
GCN 39547 table
GRB_name GRB250228A
GCN_number 39547
Detection_method Fermi GBM Other
ra 94.9000°
decl -46.8100°
Circular_text TITLE: GCN CIRCULAR NUMBER: 39547 SUBJECT: GRB 250228A: Fermi GBM Final Localization DATE: 25/03/02 09:43:31 GMT FROM: Marianna Dafčíková at Masaryk University <500025@mail.muni.cz> The Fermi GBM team reports the detection of a likely SHORT GRB "At 07:23:46.16 UT on 28 February 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250228A (trigger 762420231/250228308). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 94.90, Dec = -46.81 (J2000 degrees, equivalent to J2000 6h 19m, -46d 48'), with a statistical uncertainty of 11.91 degrees. The angle from the Fermi LAT boresight is 27 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250228308/quicklook/glg_skymap_all_bn250228308.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/bn250228308/quicklook/glg_healpix_all_bn250228308.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250228308/quicklook/glg_lc_medres34_bn250228308.gif"
GCN 39674 table
GRB_name GRB250228A
GCN_number 39674
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 39674 SUBJECT: GRB 250228A: Swift/BAT-GUANO localization skymap of a likely short burst DATE: 25/03/11 20:10:49 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 250228A onboard (T0: 2025-02-28T07:23:46.16 UTC, Fermi GCN 39547) 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 8.03 in a 0.128 s analysis time bin, starting at T0 - 0.096 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 14,714 deg2 and the 50% credible area is 5,217 deg2. The integrated probability inside the coded field of view is <1%. The joint NITRATES+GBM localization has a 90% credible area of 1171 deg2 and a 50% credible area of 304 deg2 A plot of the probability skymap can be viewed here: [skymap_plot](https://guano.swift.psu.edu/trigger_report?id=762420261/#:~: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/762420261/0_n_PROBMAP) [joint_skymap_fits_file](https://guano.swift.psu.edu/files/762420261/0_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=762420261 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 39680 table
GRB_name GRB250228A
GCN_number 39680
Detection_method Fermi GBM Det
t_trigger 7:23:46.160 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 39680 SUBJECT: GRB 250228A: Fermi GBM Observation DATE: 25/03/12 07:13:25 GMT FROM: Utkarsh Pathak at IIT Bombay U. Pathak (IIT Bombay), M. Dafčíková (Masaryk U.), and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 07:23:46.16 UT on 28 February 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250228A (trigger 762420231/250228308). which was also detected by Swift/BAT-GUANO (Ronchini et al. 2025, GCN 39674). The Fermi GBM on-ground location is consistent with the Swift/BAT position. The angle from the Fermi LAT boresight is 27 degrees. The GBM light curve consists of a weak pulse from a single emission episode with a duration (T90) of about 0.6 s (50-300 keV). The time-averaged spectrum from T0-0.5 to T0+0.3 s is best fit by a simple power law function with index -1.45 +/- 0.1. The event fluence (10-1000 keV) in this time interval is (2.0 +/- 0.3)E-07 erg/cm^2. The 64-ms peak photon flux measured starting from T0-0.064 s in the 10-1000 keV band is 4.3 +/- 0.9 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/"