GRB250331D

This page lists all entries on GRB250331D in GRBweb

Summary Fermi GBM GCN 39961 GCN 39979 GCN 39982 GCN 39990 GCN 39998 GCN 40004 GCN 40005 GCN 40079

Summary table
Variable Value Source
GRB_name_Fermi GRB250331243
T0 5:49:15.735 UTC Fermi_GBM
ra 48.6572° GCN_circulars,Swift-XRT Other
decl 62.2833° GCN_circulars,Swift-XRT Other
T90 8.96 s Fermi_GBM
T90_error 1.81 s Fermi_GBM
T90_start 5:49:15.735 UTC Fermi_GBM
fluence 5.62e-07 erg/cm² Fermi_GBM
fluence_error 3.15e-08 erg/cm² Fermi_GBM
T100 8.96 s
GBM_located False
mjd 60765.242543229164 Fermi_GBM
Fermi GBM table
GRB_name_Fermi GRB250331243
trigger_name bn250331243
ra 21.1300°
decl 55.7300°
pos_error 7.81e+00°
datum 2025-03-31
t_trigger 5:49:17.015 UTC
T90 8.96 s
T90_error 1.81 s
T90_start 5:49:15.735 UTC
fluence 5.62e-07 erg/cm²
fluence_error 3.15e-08 erg/cm²
flux_1024 2.23e+00 erg/cm²/s
flux_1024_error 2.23e-01 erg/cm²/s
flux_1024_time -6.40e-01 erg/cm²/s
flux_64 3.52e+00 erg/cm²/s
flux_64_error 1.10e+00 erg/cm²/s
GCN 39961 table
GRB_name GRB250331D
GCN_number 39961
Detection_method Fermi GBM final loc
t_trigger 5:49:17 UTC
ra 21.1000°
decl 55.7000°
Circular_text TITLE: GCN CIRCULAR NUMBER: 39961 SUBJECT: GRB 250331D: Fermi GBM Final Real-time Localization DATE: 25/03/31 05:59:53 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 05:49:17 UT on 31 Mar 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250331D (trigger 765092962.014718 / 250331243). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 21.1, Dec = 55.7 (J2000 degrees, equivalent to J2000 01h 24m, 55d 42'), with a statistical uncertainty of 13.9 degrees. The angle from the Fermi LAT boresight is 12.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250331243/quicklook/glg_skymap_all_bn250331243.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/bn250331243/quicklook/glg_healpix_all_bn250331243.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250331243/quicklook/glg_lc_medres34_bn250331243.gif
GCN 39979 table
GRB_name GRB250331D
GCN_number 39979
Detection_method Swift Other
ra 48.5254°
decl 62.3060°
Circular_text TITLE: GCN CIRCULAR NUMBER: 39979 SUBJECT: GRB 250331D: Swift/BAT-GUANO arcminute localization of a burst during slew DATE: 25/03/31 17:36:04 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 250331D onboard (T0: 2025-03-31T05:49:17 UTC, Fermi GCN 39961). 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 burst occurred during a Swift slew. The imaging is performed using BatAnalysis tools (Parsotan et al. 2025 [https://arxiv.org/abs/2502.00278](https://arxiv.org/abs/2502.00278)). A confident location is found for the burst with SNR of 11.6 The BAT position is RA, Dec = 48.52543, 62.30596 deg which is RA(J2000) = 03h 14m 06.10s Dec(J2000) = +62d 18’ 21.5″ with an estimated uncertainty of 5 arcmin. This position is consistent with the Ferm/GBM localization (GCN 39961). XRT and UVOT follow-up has been requested. Results of follow-up observations will be reported in future circulars. 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 39982 table
GRB_name GRB250331D
GCN_number 39982
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 39982 SUBJECT: GRB 250331D: Swift ToO observations DATE: 25/03/31 18:37:26 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a ToO observation of the Swift/BAT-detected event GRB 250331D. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021825 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the Swift/BAT event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team.
GCN 39990 table
GRB_name GRB250331D
GCN_number 39990
Detection_method Fermi GBM Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 39990 SUBJECT: Fermi GRB 250331D: Global MASTER-Net observations report DATE: 25/04/01 00:03:05 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-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 250331D ( Fermi GBM team, GCN 39961) errorbox 62486 sec after notice time and 62523 sec after trigger time at 2025-03-31 23:11:20 UT, with upper limit up to 17.9 mag. The observations began at zenith distance = 71 deg. The sun altitude is -35.8 deg. The galactic latitude b = -7 deg., longitude l = 128 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2829033 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 62554 | 2025-03-31 23:11:20 | MASTER-Kislovodsk | (02h 54m 34.96s , +65d 33m 33.8s) | C | 60 | 17.7 | 63431 | 2025-03-31 23:25:58 | MASTER-Kislovodsk | (02h 54m 36.68s , +65d 33m 23.8s) | C | 60 | 17.9 | 64508 | 2025-03-31 23:43:54 | MASTER-Kislovodsk | (02h 53m 45.13s , +65d 44m 21.5s) | C | 60 | 17.7 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
GCN 39998 table
GRB_name GRB250331D
GCN_number 39998
Detection_method Swift-XRT Other
ra 48.6572°
decl 62.2833°
Circular_text TITLE: GCN CIRCULAR NUMBER: 39998 SUBJECT: GRB 250331D: Swift-XRT observations DATE: 25/04/01 08:59:42 GMT FROM: Phil Evans at U of Leicester A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), S. Dichiara (PSU), J.A. Kennea (PSU), D.N. Burrows (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Swift/BAT-detected burst GRB 250331D, collecting 5.3 ks of Photon Counting (PC) mode data between T0+45.2 ks and T0+68.1 ks. Two uncatalogued X-ray sources have been detected within the estimated 3-sigma Swift/BAT error region (493 arcsec), however none of them is above the RASS limit or shows definitive signs of fading. Therefore, at the present time we cannot identify which, if any, is the afterglow. Details of these sources are given below: Source 2: RA (J2000): 48.6572 = 03:14:37.72 Dec (J2000): +62.2833 = +62:16:59.7 Error: 3.5 arcsec (radius, 90% conf. [Enhanced position]) Count-rate: (7.4 [+1.6, -1.4])e-3 ct s^-1 Distance: 235 arcsec from Swift/BAT position. Flux: (3.18 [+0.67, -0.61])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV) Source 4: RA (J2000): 48.7705 = 03:15:4.93 Dec (J2000): +62.3734 = +62:22:24.1 Error: 5.9 arcsec (radius, 90% conf.) Count-rate: (1.77 [+0.95, -0.72])e-3 ct s^-1 Distance: 476 arcsec from Swift/BAT position. Flux: (1.19 [+0.64, -0.49])e-10 erg cm^-2 s^-1 (observed, 0.3-10 keV) A catalogued source was also detected within the estimated 3-sigma Swift/BAT error region (493 arcsec). Two uncatalogued sources were also detected too far from the GRB position to be likely afterglow candidates. The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/ToO_GRBs/00021825. This circular is an official product of the Swift-XRT team.
GCN 40004 table
GRB_name GRB250331D
GCN_number 40004
Detection_method Fermi GBM Det
t_trigger 5:49:17.010 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 40004 SUBJECT: GRB 250331D: Fermi GBM observation DATE: 25/04/01 13:33:45 GMT FROM: Elisabetta Bissaldi at Politecnico and INFN Bari E. Bissaldi (Politecnico and INFN Bari), C. Meegan (UAH) and A. Holzmann Airasca (Univ. Trento and INFN Bari) report on behalf of the Fermi GBM Team: "At 05:49:17.01 UT on 31 March 2025, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 250331D (trigger 765092962 / 250331243), which was also detected by the Swift/BAT-GUANO (Ronchini et al. 2025, GCN 39979). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 27 degrees. The GBM light curve consists of a single emission episode with a duration (T90) of about 9 s (50-300 keV). The time-averaged spectrum from T0-2.5 s to T0+6.4 s is adequately fit by a power law function with an exponential high-energy cutoff. The power law index is -1.12 +/- 0.27 and the cutoff energy, parameterized as Epeak, is 91 +/- 20 keV. The event fluence (10-1000 keV) in this time interval is (6.1 +/- 0.8)E-07 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.64 s in the 10-1000 keV band is 2.2 +/- 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/"
GCN 40005 table
GRB_name GRB250331D
GCN_number 40005
Detection_method Optical
ra 48.2603°
decl 62.3076°
Circular_text TITLE: GCN CIRCULAR NUMBER: 40005 SUBJECT: GRB250331D: AbAO optical observations DATE: 25/04/01 14:15:27 GMT FROM: Alexei Pozanenko at IKI, Moscow N. Pankov (HSE, IKI), R. Ya. Inasaridze (AbAO), A. Pozanenko (IKI) report on behalf of IKI GRB-FuN: We observed the entire localisation region of BAT-GUANO/Swift of GRB250331D (Ronchini et al., GCN 39979), initially detected by GBM/Fermi (Fermi GBM team, GCN 39961) with AS-32 telescope of AbAO starting on 2025-03-31 (UT) 18:56:37. We report the results of optical transient searches in five XRT/Swift localisations reported in https://www.swift.ac.uk/ToO_GRBs/00021825/ and (Melandri et al., GCN 39998). Details of the preliminary photometry of the stacked image and the sources detected so far are given below. Date UT start t-T0 Filter Exp. UL(3sigma) Telescope (mid, d) (s) 2025-03-31 18:56:37 0.56447 R 61x60 20.8 AS-32 XRT #1 ------ RA = 48.26026d Dec = 62.30756d Err90 = 5.1" Inside the XRT error circle the single source is detected: RA = 48.25957d +/- 0.05" Dec = 62.30756 +/- 0.02" R(AbAO) = 13.24 +/- 0.05 USNO-B1.0 R2 = 13.39 XRT #2 ------ RA = 48.65718d Dec = 62.28326d Err90 = 3.5" Inside the XRT error circle the single source is detected: RA = 48.66142d +/- 0.14" Dec = 62.28324d +/- 0.07" R(AbAO) = 18.72 +/- 0.07 USNO-B1.0 R2 = 18.97 XRT #3 ------ RA = 48.86152d Dec = 62.34017d Err90 = 7.0" Inside the XRT error circle the single source is detected: RA = 48.85897d +/- 0.12" Dec = 48.85897d +/- 0.06" R(AbAO) = 18.64 +/- 0.07 USNO-B1.0 R2 = 18.93 XRT #4 ------ RA = 48.77053d Dec = 62.37337d Err90 = 5.9" Inside the XRT error circle the single source is detected: RA = 48.76831d +/- 0.3" Dec = 62.37292d +/- 0.3" R(AbAO) = 19.68 +/- 0.26 USNO-B1.0 R2 = 19.94 XRT #5 ------ RA = 48.3703896d Dec = 62.10607d Err90 = 6.9" Inside the XRT error circle the single source is detected: RA = 48.37039d +/- 0.3" Dec = 62.10664d +/- 0.3" R(AbAO) ~ 21.0 PS1 r = 21.17 +/- 0.15, i = 20.21 +/- 0.06 We did not identify any variable sources in any of the XRT localisations ( https://www.swift.ac.uk/ToO_GRBs/00021825/).
GCN 40079 table
GRB_name GRB250331D
GCN_number 40079
Detection_method Swift-XRT Other
ra 48.6572°
decl 62.2833°
Circular_text TITLE: GCN CIRCULAR NUMBER: 40079 SUBJECT: GRB 250331D: Swift-XRT afterglow detection DATE: 25/04/05 12:24:26 GMT FROM: Phil Evans at U of Leicester A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), S. Dichiara (PSU), J.A. Kennea (PSU), D.N. Burrows (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has conducted further observations of the field of the Swift/BAT-detected burst GRB 250331D. The observations now extend from T0+45.3 ks to T0+406.9 ks and have a total exposure time of 8.6 ks. Of the sources previously reported, "Source 2" is fading with >3-sigma significance, and is therefore likely the GRB afterglow. Using 3064 s of PC mode data and 2 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 48.65718, +62.28326 which is equivalent to: RA (J2000): 03h 14m 37.72s Dec(J2000): +62d 16' 59.8" with an uncertainty of 3.5 arcsec (radius, 90% confidence). This position is 3.9 arcmin from the Swift/BAT position. There is evidence that the source may be fading, however we cannot constrain the decay at the current time. The results of the XRT-team automatic analysis of the likely afterglow are at https://www.swift.ac.uk/ToO_GRBs/00021825/Source2.php. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021825. This circular is an official product of the Swift-XRT team.