GRB 250302A
GCN Circular 39548
Subject
GRB 250302A: Fermi GBM Final Real-time Localization
Date
2025-03-02T13:57:01Z (3 months ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 13:46:32 UT on 2 Mar 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250302A (trigger 762615997.991246 / 250302574).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 236.4, Dec = 12.2 (J2000 degrees, equivalent to J2000 15h 45m, 12d 11'), with a statistical uncertainty of 5.4 degrees.
The angle from the Fermi LAT boresight is 67.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250302574/quicklook/glg_skymap_all_bn250302574.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/bn250302574/quicklook/glg_healpix_all_bn250302574.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250302574/quicklook/glg_lc_medres34_bn250302574.gif
GCN Circular 39552
Subject
Fermi GRB 250302A: Global MASTER-Net observations report
Date
2025-03-02T21:33:42Z (3 months ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
email
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 250302A ( Fermi GBM team, GCN 39548) errorbox 21539 sec after notice time and 21575 sec after trigger time at 2025-03-02 19:46:08 UT, with upper limit up to 20.4 mag. The observations began at zenith distance = 43 deg. The sun altitude is -36.5 deg.
MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 250302A errorbox 22677 sec after notice time and 22713 sec after trigger time at 2025-03-02 20:05:06 UT, with upper limit up to 17.7 mag. The observations began at zenith distance = 77 deg. The sun altitude is -50.2 deg.
The galactic latitude b = 46 deg., longitude l = 22 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2796892
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
21605 | 2025-03-02 19:46:08 | MASTER-Tunka | (15h 31m 17.49s , +16d 30m 25.9s) | C | 60 | 19.8 |
21665 | 2025-03-02 19:46:08 | MASTER-Tunka | (15h 31m 17.49s , +16d 30m 25.9s) | C | 180 | 20.3 | Coadd
21678 | 2025-03-02 19:47:20 | MASTER-Tunka | (15h 39m 40.44s , +16d 31m 15.0s) | C | 60 | 19.8 |
21738 | 2025-03-02 19:47:20 | MASTER-Tunka | (15h 39m 40.44s , +16d 31m 14.9s) | C | 180 | 20.3 | Coadd
22064 | 2025-03-02 19:53:47 | MASTER-Tunka | (15h 41m 02.12s , +18d 25m 27.9s) | C | 60 | 19.8 |
22124 | 2025-03-02 19:53:47 | MASTER-Tunka | (15h 41m 02.11s , +18d 25m 27.9s) | C | 180 | 20.4 | Coadd
22137 | 2025-03-02 19:55:00 | MASTER-Tunka | (15h 49m 28.20s , +18d 23m 04.7s) | C | 60 | 19.7 |
22197 | 2025-03-02 19:55:00 | MASTER-Tunka | (15h 49m 28.20s , +18d 23m 04.6s) | C | 180 | 20.3 | Coadd
22210 | 2025-03-02 19:56:13 | MASTER-Tunka | (15h 31m 19.81s , +16d 32m 30.0s) | C | 60 | 19.9 |
22283 | 2025-03-02 19:57:25 | MASTER-Tunka | (15h 39m 34.02s , +16d 30m 56.3s) | C | 60 | 19.9 |
22586 | 2025-03-02 20:02:28 | MASTER-Tunka | (15h 23m 46.12s , +16d 31m 47.0s) | C | 60 | 20.0 |
22646 | 2025-03-02 20:02:28 | MASTER-Tunka | (15h 23m 46.12s , +16d 31m 47.0s) | C | 180 | 20.3 | Coadd
22744 | 2025-03-02 20:05:06 | MASTER-Kislovodsk | (15h 31m 05.90s , +18d 24m 03.2s) | C | 60 | 13.6 |
22820 | 2025-03-02 20:06:23 | MASTER-Tunka | (15h 40m 59.24s , +18d 26m 16.1s) | C | 60 | 19.8 |
22823 | 2025-03-02 20:06:26 | MASTER-Kislovodsk | (15h 20m 24.78s , +14d 35m 08.1s) | C | 60 | 14.4 |
22893 | 2025-03-02 20:07:36 | MASTER-Tunka | (15h 49m 30.08s , +18d 24m 37.9s) | C | 60 | 19.8 |
22904 | 2025-03-02 20:07:46 | MASTER-Kislovodsk | (15h 28m 43.31s , +14d 36m 18.2s) | C | 60 | 13.6 |
22967 | 2025-03-02 20:08:49 | MASTER-Tunka | (15h 31m 14.39s , +16d 31m 14.0s) | C | 60 | 19.8 |
23042 | 2025-03-02 20:10:04 | MASTER-Tunka | (15h 39m 39.86s , +16d 31m 01.5s) | C | 60 | 19.7 |
23160 | 2025-03-02 20:12:03 | MASTER-Kislovodsk | (15h 36m 12.34s , +14d 34m 34.1s) | C | 60 | 15.6 |
23240 | 2025-03-02 20:13:23 | MASTER-Kislovodsk | (15h 44m 23.73s , +14d 35m 43.7s) | C | 60 | 14.7 |
23337 | 2025-03-02 20:14:59 | MASTER-Tunka | (15h 23m 42.86s , +16d 33m 11.8s) | C | 60 | 19.9 |
23413 | 2025-03-02 20:16:15 | MASTER-Tunka | (15h 30m 58.44s , +12d 44m 41.7s) | C | 60 | 19.8 |
23473 | 2025-03-02 20:16:15 | MASTER-Tunka | (15h 30m 58.44s , +12d 44m 41.7s) | C | 180 | 20.1 | Coadd
23480 | 2025-03-02 20:17:22 | MASTER-Kislovodsk | (15h 31m 02.91s , +18d 23m 56.7s) | C | 60 | 16.9 |
23486 | 2025-03-02 20:17:29 | MASTER-Tunka | (15h 39m 05.45s , +12d 43m 05.6s) | C | 60 | 19.7 |
23546 | 2025-03-02 20:17:29 | MASTER-Tunka | (15h 39m 05.45s , +12d 43m 05.5s) | C | 180 | 20.1 | Coadd
23560 | 2025-03-02 20:18:42 | MASTER-Kislovodsk | (15h 20m 23.76s , +14d 37m 26.2s) | C | 60 | 17.0 |
23561 | 2025-03-02 20:18:43 | MASTER-Tunka | (15h 41m 05.86s , +18d 25m 13.1s) | C | 60 | 19.8 |
23637 | 2025-03-02 20:19:59 | MASTER-Tunka | (15h 49m 27.79s , +18d 25m 54.4s) | C | 60 | 19.7 |
23639 | 2025-03-02 20:20:02 | MASTER-Kislovodsk | (15h 28m 43.11s , +14d 36m 08.7s) | C | 60 | 16.8 |
23712 | 2025-03-02 20:21:15 | MASTER-Tunka | (15h 31m 16.75s , +16d 31m 55.3s) | C | 60 | 19.9 |
23772 | 2025-03-02 20:21:15 | MASTER-Tunka | (15h 31m 16.75s , +16d 31m 55.1s) | C | 180 | 19.8 | Coadd
23785 | 2025-03-02 20:22:27 | MASTER-Tunka | (15h 39m 40.80s , +16d 32m 51.7s) | C | 60 | 19.8 |
23799 | 2025-03-02 20:22:42 | MASTER-Kislovodsk | (15h 21m 17.81s , +12d 41m 36.6s) | C | 60 | 17.1 |
23959 | 2025-03-02 20:25:22 | MASTER-Kislovodsk | (15h 36m 07.19s , +14d 35m 28.8s) | C | 60 | 17.1 |
24039 | 2025-03-02 20:26:41 | MASTER-Kislovodsk | (15h 44m 26.50s , +14d 36m 37.5s) | C | 60 | 17.0 |
24080 | 2025-03-02 20:27:23 | MASTER-Tunka | (15h 23m 42.84s , +16d 32m 51.8s) | C | 60 | 19.9 |
24154 | 2025-03-02 20:28:37 | MASTER-Tunka | (15h 30m 58.25s , +12d 44m 31.8s) | C | 60 | 19.7 |
24230 | 2025-03-02 20:29:53 | MASTER-Tunka | (15h 39m 07.48s , +12d 45m 31.1s) | C | 60 | 19.7 |
24278 | 2025-03-02 20:30:40 | MASTER-Kislovodsk | (15h 31m 07.61s , +18d 24m 25.8s) | C | 60 | 17.4 |
24305 | 2025-03-02 20:31:07 | MASTER-Tunka | (15h 41m 01.62s , +18d 25m 42.8s) | C | 60 | 19.8 |
24365 | 2025-03-02 20:31:07 | MASTER-Tunka | (15h 41m 01.62s , +18d 25m 42.8s) | C | 180 | 20.2 | Coadd
24749 | 2025-03-02 20:38:31 | MASTER-Tunka | (15h 30m 53.25s , +16d 35m 14.6s) | C | 60 | 19.9 |
24939 | 2025-03-02 20:41:41 | MASTER-Kislovodsk | (15h 21m 11.94s , +12d 41m 22.0s) | C | 60 | 17.7 |
25098 | 2025-03-02 20:44:21 | MASTER-Kislovodsk | (15h 36m 07.54s , +14d 36m 59.1s) | C | 60 | 17.5 |
25178 | 2025-03-02 20:45:41 | MASTER-Kislovodsk | (15h 44m 23.92s , +14d 35m 10.2s) | C | 60 | 17.4 |
25423 | 2025-03-02 20:49:46 | MASTER-Tunka | (15h 23m 44.45s , +16d 35m 47.7s) | C | 60 | 20.0 |
25497 | 2025-03-02 20:50:59 | MASTER-Tunka | (15h 30m 54.18s , +12d 45m 40.7s) | C | 60 | 19.9 |
25569 | 2025-03-02 20:52:11 | MASTER-Tunka | (15h 39m 10.58s , +12d 46m 23.3s) | C | 60 | 19.8 |
25643 | 2025-03-02 20:53:25 | MASTER-Tunka | (15h 40m 57.76s , +18d 27m 42.0s) | C | 60 | 20.0 |
25715 | 2025-03-02 20:54:38 | MASTER-Tunka | (15h 49m 22.96s , +18d 28m 04.2s) | C | 60 | 19.8 |
25788 | 2025-03-02 20:55:51 | MASTER-Tunka | (15h 31m 18.68s , +16d 34m 38.3s) | C | 60 | 19.8 |
25861 | 2025-03-02 20:57:04 | MASTER-Tunka | (15h 39m 32.28s , +16d 33m 01.3s) | C | 60 | 19.8 |
26164 | 2025-03-02 21:02:06 | MASTER-Tunka | (15h 23m 47.97s , +16d 36m 20.0s) | C | 60 | 19.7 |
26237 | 2025-03-02 21:03:20 | MASTER-Tunka | (15h 30m 50.25s , +12d 47m 05.1s) | C | 60 | 19.6 |
26311 | 2025-03-02 21:04:33 | MASTER-Tunka | (15h 39m 02.80s , +12d 47m 29.2s) | C | 60 | 19.5 |
26385 | 2025-03-02 21:05:48 | MASTER-Tunka | (15h 41m 03.56s , +18d 28m 19.9s) | C | 60 | 18.6 |
26460 | 2025-03-02 21:07:03 | MASTER-Tunka | (15h 46m 29.50s , +12d 46m 38.1s) | C | 60 | 19.8 |
26537 | 2025-03-02 21:08:19 | MASTER-Tunka | (15h 54m 41.53s , +12d 44m 47.4s) | C | 60 | 19.8 |
26838 | 2025-03-02 21:13:21 | MASTER-Tunka | (15h 23m 46.02s , +16d 36m 09.2s) | C | 60 | 20.1 |
26914 | 2025-03-02 21:14:37 | MASTER-Tunka | (15h 30m 49.86s , +12d 46m 41.0s) | C | 60 | 20.0 |
27078 | 2025-03-02 21:17:20 | MASTER-Tunka | (15h 39m 08.10s , +12d 47m 46.3s) | C | 60 | 20.0 |
27150 | 2025-03-02 21:18:33 | MASTER-Tunka | (15h 46m 26.15s , +12d 46m 38.9s) | C | 60 | 20.0 |
27222 | 2025-03-02 21:19:44 | MASTER-Tunka | (15h 54m 37.57s , +12d 47m 02.5s) | C | 60 | 20.0 |
27300 | 2025-03-02 21:21:02 | MASTER-Tunka | (15h 38m 21.62s , +14d 40m 25.5s) | C | 60 | 20.1 |
27373 | 2025-03-02 21:22:15 | MASTER-Tunka | (15h 46m 43.50s , +14d 39m 54.8s) | C | 60 | 20.1 |
27442 | 2025-03-02 21:23:24 | MASTER-Tunka | (15h 55m 28.03s , +10d 51m 13.2s) | C | 60 | 20.0 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 39675
Subject
GRB 250302A: Swift/BAT-GUANO localization skymap of a burst
Date
2025-03-11T20:10:52Z (3 months ago)
Edited On
2025-03-12T12:34:52Z (3 months ago)
From
Samuele Ronchini at PSU <sjs8171@psu.edu>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Jimmy DeLaunay at Penn State <delauj2@gmail.com>
Via
Web form
James DeLaunay (PSU), Samuele Ronchini (PSU), Aaron Tohuvavohu (Caltech), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:
Swift/BAT did not localize GRB 250302A onboard (T0: 2025-03-02T13:46:32.99 UTC, Fermi trig 762615997)
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 17.3 in a 16.384 s analysis time bin, starting at T0 - 4.096 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 2,445 deg2 and the 50% credible area is 462 deg2.
The integrated probability inside the coded field of view is <1%.
The NITRATES skymap is consistent with the Fermi localization reported in the final position notice (GCN 39548). The combined Fermi/GBM+NITRATES 90% credible area is 152 deg2 and the 50% credible area is 46 deg2.
A plot of the probability skymap can be viewed here:
[skymap_plot](https://guano.swift.psu.edu/trigger_report?id=762616028/#:~: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/762616028/0_n_PROBMAP)
[joint_skymap_fits_file](https://guano.swift.psu.edu/files/762616028/0_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=762616028
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 Circular 39688
Subject
GRB 250302A: Fermi GBM Observation
Date
2025-03-12T17:18:02Z (3 months ago)
From
Marianna Dafčíková at Masaryk University <500025@mail.muni.cz>
Via
Web form
M. Dafcikova (MUNI) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 13:46:32.99 UT on 02 March 2025, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 250302A (trigger 762615997/250302574).
which was also detected by Swift/BAT-GUANO (DeLaunay et al. 2025, GCN 39675).
The Fermi GBM on-ground location is consistent with the Swift/BAT position.
The angle from the Fermi LAT boresight is 67 degrees.
The GBM light curve consists of multiple peaks with a duration (T90)
of about 56 s (50-300 keV). The time-averaged spectrum
from T0-3.6 to T0+71.2 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.49 +/- 0.06 and the cutoff energy,
parameterized as Epeak, is 394 +/- 135 keV.
The event fluence (10-1000 keV) in this time interval is
(8.8 +/- 0.5)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+10 s in the 10-1000 keV band is 2.5 +/- 0.2 ph/s/cm^2.
A Band function fits the spectrum equally well with Epeak = 324 +/- 194
keV, alpha = -1.48 +/- 0.09 and beta = -2.0 +/- 0.3.
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/"