GRB 231004A
GCN Circular 34795
Subject
GRB 231004A: Fermi GBM Final Real-time Localization
Date
2023-10-04T08:33:54Z (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 LONG GRB
At 08:23:35 UT on 4 Oct 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 231004A (trigger 718100620.108376 / 231004350).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 68.3, Dec = -9.9 (J2000 degrees, equivalent to J2000 04h 33m, -9d 54'), with a statistical uncertainty of 3.4 degrees.
The angle from the Fermi LAT boresight is 94.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231004350/quicklook/glg_skymap_all_bn231004350.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/bn231004350/quicklook/glg_healpix_all_bn231004350.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231004350/quicklook/glg_lc_medres34_bn231004350.gif
GCN Circular 34804
Subject
GRB 231004A: CALET Gamma-Ray Burst Monitor detection
Date
2023-10-05T18:15:41Z (2 years ago)
From
Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>
Via
Web form
S. Ricciarini (U of Florence), A. Yoshida, T. Sakamoto,
S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U),
S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii, Y. Akaike,
K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The long GRB 231004A (Fermi GBM Final Real-time Localization: Fermi GBM team,
GCN Circ. 34795) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 08:23:32.70 UTC on 4 October 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1380443018/).
The burst signal was seen by only the SGM detector.
The burst light curve shows a multi-peaked structure that starts
at T+2.1 sec, peaks at T+2.9 sec, and ends at T+4.1 sec.
The T90 and T50 durations measured by the SGM data are 1.7 +/- 0.2 sec
and 1.1 +/- 0.3 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1380443018/index.html
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 34812
Subject
GRB 231004A: Glowbug gamma-ray detection
Date
2023-10-11T19:55:47Z (2 years ago)
From
C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>
Via
Web form
M. Kerr, C.C. Cheung, 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 231004A, which was also detected by Fermi/GBM and CALET (GCN 34795, 34804).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2023-10-04 08:23:33.360 with a duration of 4.1 s and a total significance of about 29.0 sigma. The light curve comprises a single broad 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=1.3 and a cutoff energy ("Epeak") of 298 keV. The modeled 10-10000 keV fluence is 2.2e-06 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 34868
Subject
GRID detection of GRB 231004A
Date
2023-10-21T13:16:40Z (2 years ago)
From
GRID Student Team at Tsinghua University <grid@tsinghua.edu.cn>
Via
Web form
Chenyu Wang and Zirui Yang report on behalf of the GRID Collaboration:
The long-duration GRB 231004A (Fermi/GBM detection: GCN Circular 34795, IceCube detection: GCN Circular 34797, CALET detection: GCN Circular 34804, Glowbug detecton: GCN Circular 34812) was also detected with three GRID detectors, GRID-03B, GRID-04, and GRID-07, onboard two different CubeSats.
The event was triggered by GRID on 2023-10-04 at 08:23:35.0 UTC. The measured burst duration (T90) in the 30-2000 keV range is approximately 6.1 +/- 1.0 seconds.
GRID is a student-led project to monitor the transient gamma-ray sky with multiple detectors onboard different nanosatellites in the era of multi-messenger astronomy. For more information about GRID, please refer to the following references: https://doi.org/10.1007/s10686-019-09636-w and https://doi.org/10.1007/s10686-021-09819-4.