GRB 221126A
GCN Circular 32985
Subject
GRB 221126A: Fermi GBM Final Real-time Localization
Date
2022-11-26T13:18:03Z (3 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
The Fermi GBM team reports the detection of a likely LONG GRB
At 13:07:29 UT on 26 Nov 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 221126A (trigger 691160854.94316 / 221126547).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 143.5, Dec = 13.1 (J2000 degrees, equivalent to J2000 09h 33m, 13d 05'), with a statistical uncertainty of 1.2 degrees.
The angle from the Fermi LAT boresight is 22.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn221126547/quicklook/glg_skymap_all_bn221126547.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn221126547/quicklook/glg_healpix_all_bn221126547.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn221126547/quicklook/glg_lc_medres34_bn221126547.gif
GCN Circular 32987
Subject
GRB 221126A: Swift/BAT-GUANO detection outside the coded FOV
Date
2022-11-27T18:14:59Z (3 years ago)
From
Aaron Tohuvavohu at U Toronto <aaron.tohu@gmail.com>
Gayathri Raman (PSU), James DeLaunay (UAlabama), Aaron Tohuvavohu (U
Toronto), Jamie A. Kennea (PSU) report:
Swift/BAT did not localize GRB 221126A onboard (T0:
2022-11-26T13:07:29 UTC, Fermi/GBM GCN 32985).
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,
arXiv:2111.01769), detects the burst with a sqrt(TS) of 11.9 in a
4.096 s analysis time bin.
NITRATES results indicate a burst coming from outside the FOV, with
DeltaLLHOut of -1.
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 32990
Subject
GRB 221126A: AstroSat CZTI detection
Date
2022-11-28T13:58:27Z (3 years ago)
From
Gaurav Waratkar at IIT,Bombay <gauravwaratkar@iitb.ac.in>
M. Dixit (IITB), V. Prasad (IUCAA), G. Waratkar (IITB), A. Vibhute
(IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA),
A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the
AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al.,
2021, JApA, 42, 73) showed the detection of long GRB 221126A which was
also detected by Fermi-GBM (GCN Cir. 32985) and Swift/BAT-GUANO (GCN
Cir. 32987).
The source was clearly detected in the 20-200 keV energy range. The
light curve peaks at 2022-11-26 13:07:28.950 UTC. The measured peak
count rate associated with the burst is 590.6 (+51.2, -55.0) counts/s
above the background in the combined data of all quadrants, with a total
of 2093 (+254, -271) counts. The local mean background count rate was
433.4 (+2.7, -3.0) counts/s. Using cumulative rates, we measure a T90 of
4.89 (+4.45, -1.03) s.
It was also clearly detected in the CsI anticoincidence (Veto) detector
in the 100-500 keV energy range. The light curve peaks at 2022-11-26
13:07:28.640 UTC. The measured peak count rate is 663.6 (+72.1, -79.1)
counts/s above the background in the combined Veto data of all
quadrants, with a total of 1770 (+234, -259) counts. The local mean
background count rate was 1410.0 (+4.9, -5.4) counts/s. We measure a T90
of 4.18 (+1.11, -1.24) s from the cumulative Veto light curve.
CZTI GRB detections are reported regularly on the payload site at
http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led
consortium of institutes across India, including VSSC, URSC, IUCAA, SAC,
and PRL. The Indian Space Research Organisation funded, managed, and
facilitated the project.
GCN Circular 32992
Subject
GRB 221126A: AGILE detection
Date
2022-11-28T17:26:49Z (3 years ago)
From
Claudio Casentini at INAF-IAPS <claudio.casentini@inaf.it>
C. Casentini, A. Ursi (INAF/IAPS), F. Lucarelli (SSDC, and INAF/OAR),
M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), C. Pittori, F.
Verrecchia
(SSDC, and INAF/OAR), A. Argan, M. Cardillo, Y. Evangelista, L. Foffano,
E. Menegoni, G. Piano (INAF/IAPS), A. Addis, L. Baroncelli, A. Bulgarelli,
A. Di Piano, V. Fioretti, G. Panebianco, N. Parmiggiani (INAF/OAS-Bologna),
M. Romani (INAF/OA-Brera), M. Marisaldi (INAF/OAS-Bologna, Bergen
University),
M. Pilia, A. Trois (INAF/OA Cagliari), F. Longo (Uni. Trieste, INFN
Trieste),
I. Donnarumma (ASI), A. Giuliani (INAF/IASF-Mi) and P. Tempesta
(TeleSpazio),
report on behalf of the AGILE Team:
The AGILE satellite detected the GRB 221126A at T0 = 2022-11-26 13:07:29 s
(UTC), reported by Fermi/GBM (GCN #32985), Swift/BAT (GCN #32987) and
AstroSat CZTI (GCN #32990).
The burst is clearly visible in the AGILE scientific ratemeters of the
AntiCoincidence, (AC-Top; 50-200 keV) detector. The event lasted about 6 s
and it released a total number of 25792 counts in the AC-Top detector
(above a background rate of 3388 Hz). The AGILE ratemeters light curves
can be found at http://www.agilescienceapp.it/notices/GRB221126A.png.
At the T0, the event was 51.82 deg off-axis.
Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert
Notices can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html.
GCN Circular 32994
Subject
GRB 221126A: Fermi GBM observation
Date
2022-11-29T11:59:03Z (3 years ago)
From
Andreas von Kienlin at MPE <azk@mpe.mpg.de>
A. von Kienlin (MPE) and C. Meegan (UAH) report on behalf of the Fermi GBM
Team:
"At 13:07:29.94 UT on 26 November 2022, the Fermi Gamma-Ray Burst Monitor
(GBM)
triggered and located GRB 221126A (trigger 691160854 / 221126547).
This event was also observed by Swift/BAT-GUANO (GCN 32987), AstroSat CZTI
(GCN 32990)
and AGILE (GCN 32992).
The GBM position is reported in the Fermi-GBM Final on-ground Localization
(GCN 32985).
The angle from the Fermi LAT boresight is 22 degrees.
The GBM light curve shows a structured pulse with a duration (T90) of about
7 s (50-300 keV).
The time-averaged spectrum from T0-0.90 s to T0+8.32 s is best fit by a
power law function
with an exponential high-energy cutoff. The power law index is -0.94 +/-
0.03 and the cutoff energy,
parameterized as Epeak, is 194 +/- 8 keV
The event fluence (10-1000 keV) in this time interval is (9.29 +/- 0.02)E-06
erg/cm^2. The 1.024-sec
peak photon flux measured starting from T0+4.224 s in the 10-1000 keV band
is 15.7 +/- 0.4 ph/s/cm^2.
A Band function fits the spectrum equally well with Epeak= 190 +/- 10 keV,
alpha = -0.92 +/- 0.04
and beta = -3.1 +/- 0.6.
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/"