GRB 231123C
GCN Circular 35171
Subject
GRB 231123C: Fermi GBM Final Real-time Localization
Date
2023-11-23T20:08:55Z (2 years 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 19:58:25 UT on 23 Nov 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 231123C (trigger 722462310.383788 / 231123832).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 162.3, Dec = 45.9 (J2000 degrees, equivalent to J2000 10h 49m, 45d 53'), with a statistical uncertainty of 22.2 degrees.
The angle from the Fermi LAT boresight is 107.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231123832/quicklook/glg_skymap_all_bn231123832.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231123832/quicklook/glg_healpix_all_bn231123832.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231123832/quicklook/glg_lc_medres34_bn231123832.gif
GCN Circular 35179
Subject
GRB 231123C: Swift/BAT-GUANO detection of a short burst likely outside the coded FOV
Date
2023-11-24T18:30:16Z (2 years ago)
From
Aaron Tohuvavohu at University of Toronto <aaron.tohu@gmail.com>
Via
Web form
James DeLaunay (PSU), Gayathri Raman (PSU), Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:
Swift/BAT did not localize GRB 231123C onboard (T0: 2023-11-23T19:58:25 UTC, Fermi GBM Trig 722462310, GCN 35171).
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), detects the burst with a sqrt(TS) of 12.8 in a 0.6 s analysis time bin, starting at T0 - 0.08 s.
NITRATES results, independently, are ambiguous with respect to whether this burst originates from in or outside the BAT coded FOV, with a DeltaLLHOut of 7.6.
See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.
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 35184
Subject
GRB 231123C (short): Glowbug gamma-ray detection
Date
2023-11-24T23:38:43Z (2 years ago)
From
C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>
Via
Web form
C.C. Cheung, M. Kerr, J. E. Grove, R. Woolf (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge (MSFC), and M.S. Briggs (UAH) report:
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 231123C, which was also detected by Fermi/GBM and Swift/BAT-GUANO (GCN 35171, 35179).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2023-11-23 19:58:24.304 with a duration of 0.256 s and a total significance of about 11.5 sigma. The light curve comprises a single peak.
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=1.5 and a cutoff energy ("Epeak") of 322 keV. The modeled 10-10000 keV fluence is 2.4e-07 erg/cm^2.
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS. The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
Distribution Statement A: Approved for public release. Distribution is unlimited.
GCN Circular 35187
Subject
GRB 231123C: Insight-HXMT/HE detection
Date
2023-11-25T12:47:01Z (2 years ago)
From
yqzhang_cl@163.com
Via
Web form
Y.Q Zhang, S. L. Xiong, X. B. Li and C. K. Li
report on behalf of the Insight-HXMT team:
At 2023-11-23T19:58:25.38 (T0), Insight-HXMT/HE detected
GRB 231123C (trigger ID: HEB231123832) in a routine search of the data,
which was also observed by Fermi/GBM (Fermi GBM Team, GCN 35171),
Swift/BAT(James DeLaunay et al., GCN 35179) and
Glowbug (C. C. Cheung et al., GCN 35184).
The Insight-HXMT/HE light curve mainly consists of single
pulse with a duration (T90) of 0.41 s measured from T0-0.24 s.
The 1-ms peak rate, measured from T0-0.09 s, is 1741 cnts/sec.
The total counts from this burst is 291 counts.
URL_LC: http://twiki.ihep.ac.cn/pub/HXMT/GRBList/HEB231123832_lc.jpg
All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (deposited energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
the telescope.
Insight-HXMT is the first Chinese space X-ray telescope, which was
funded jointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about it could be found at:
http://www.hxmt.org.
GCN Circular 35205
Subject
GRB 231123C: Fermi GBM Observation
Date
2023-11-28T00:38:45Z (2 years ago)
From
Sarah Dalessi at UAH <sd0104@uah.edu>
Via
Web form
S. Dalessi (UAH), S. Lesage (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 19:58:25.38 UT on 23 November 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 231123C (trigger 722462310/231123832).
which was also detected by Swift/BAT-GUANO (J. DeLaunay et al. 2023, GCN 35179).
The Fermi Final Localization was reported in GCN 35171.
The angle from the Fermi LAT boresight is 90 degrees.
The GBM light curve single peak with a duration (T90)
of about 0.4 s (50-300 keV). The time-averaged spectrum
from T0-0.1 to T0+0.4 s is best fit by
a Power law function with alpha = -1.29 +/- 0.06.
The event fluence (10-1000 keV) in this time interval is
(3.3 +/- 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 5 +/- 1 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/"