GRB 250119C
GCN Circular 38990
Subject
GRB 250119C: Fermi GBM Final Real-time Localization
Date
2025-01-19T22:52:34Z (4 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 SHORT GRB
At 22:41:06 UT on 19 Jan 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250119C (trigger 759019271.302184 / 250119945).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 163.9, Dec = 15.1 (J2000 degrees, equivalent to J2000 10h 55m, 15d 05'), with a statistical uncertainty of 8.8 degrees.
The angle from the Fermi LAT boresight is 66.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250119945/quicklook/glg_skymap_all_bn250119945.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/bn250119945/quicklook/glg_healpix_all_bn250119945.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250119945/quicklook/glg_lc_medres34_bn250119945.gif
GCN Circular 39008
Subject
GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
Date
2025-01-22T02:44:45Z (4 months ago)
From
Samuele Ronchini at PSU <sjs8171@psu.edu>
Via
Web form
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 250119C onboard (T0: 2025-11-19T22:41:06.30 UTC, Fermi GCN 38990)
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 12.6 in a 0.256 s analysis time bin, starting at T0 - 0.064 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 12,500 deg2 and the 50% credible area is 4,093 deg2.
The integrated probability inside the coded field of view is 3%.
The NITRATES skymap is consistent with the Fermi localization.
A plot of the probability skymap can be viewed here:
[skymap_plot](https://guano.swift.psu.edu/trigger_report?id=759019301/#:~:text=Probability%20Skymap)
The probability skymap file can be downloaded from the link here
[skymap_fits_file](https://guano.swift.psu.edu/files/759019301/0_n_PROBMAP)
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=759019301
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 39030
Subject
GRB 250119C: Fermi GBM Observation
Date
2025-01-25T14:45:44Z (4 months ago)
From
Jacob Smith at Fermi-GBM Team <jrs0118@uah.edu>
Via
Web form
Jacob Smith (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
At 22:41:06.30 UT on 19 January 2025, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 250119C (trigger 759019271/250119945).
which was also detected by Swift/BAT-GUANO (Ronchini, S. et al. 2025, GCN 39008).
The Fermi GBM on-ground location is consistent with the Swift/BAT-GUANO position.
The angle from the Fermi LAT boresight is 66 degrees.
The GBM light curve consists of a single short emission episode with a duration (T90)
of about 1 s (50-300 keV). The time-averaged spectrum
from T0-0.2 to T0+0.2 s is best fit by
a power law function with an exponential high-energy cutoff. The power law index is -0.63 +/- 0.2 and the cutoff energy,
parameterized as Epeak, is 1120 +/- 420 keV.
The event fluence (10-1000 keV) in this time interval is
(5.4 +/- 0.4)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 4.9 +/- 0.7 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 Circular 39045
Subject
IPN triangulation of GRB 250119C
Date
2025-01-27T12:48:35Z (4 months ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
Web form
D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia,
and T. Cline on behalf of the Konus-Wind team,
A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,
E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team, report:
The long-duration GRB 250119C
(Fermi-GBM detection: The Fermi GBM team, GCN 38990;
Smith and Meegan, GCN 39030;
Swift-BAT/GUANO detection: Ronchini et al., GCN 39008)
was detected by Fermi (GBM trigger 759019271), Swift (BAT),
Konus-Wind, and INTEGRAL (SPI-ACS) at about 81666 s UT (22:41:06).
The burst was outside the coded field of view of the BAT.
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
158.335 (10h 33m 20s) +20.621 (+20d 37' 17")
Corners:
135.211 (09h 00m 51s) +18.215 (+18d 12' 54")
179.680 (11h 58m 43s) +14.804 (+14d 48' 15")
182.465 (12h 09m 52s) +23.952 (+23d 57' 06")
135.484 (09h 01m 56s) +27.480 (+27d 28' 47")
---------------------------------------------
The error box area is 393.4 sq. deg, and its maximum
dimension is 44.2 deg (the minimum one is 9.2 deg).
The Sun distance was 124 deg.
This localization may be improved.
The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM (GCN 38990) and Swift-BAT/GUANO (GCN 39008) localizations.
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB250119_T81666/IPN
The HEALPix triangulation map is the multi-order HEALPix in units of
probability density.