GRB 231104A
GCN Circular 34937
Subject
GRB 231104A: Fermi GBM Final Real-time Localization
Date
2023-11-04T01:57:53Z (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 01:47:28 UT on 4 Nov 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 231104A (trigger 720755253.13875 / 231104075).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 8.0, Dec = 82.1 (J2000 degrees, equivalent to J2000 00h 32m, 82d 05'), with a statistical uncertainty of 1.0 degrees.
The angle from the Fermi LAT boresight is 32.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231104075/quicklook/glg_skymap_all_bn231104075.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/bn231104075/quicklook/glg_healpix_all_bn231104075.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231104075/quicklook/glg_lc_medres34_bn231104075.gif
GCN Circular 34938
Subject
GRB 231104A: Swift detection of a bright burst
Date
2023-11-04T02:34:58Z (2 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
Via
email
K. L. Page (U Leicester), J.D. Gropp (PSU), D. M. Palmer (LANL) and
M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 01:47:39 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 231104A (trigger=1194500). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 23.789, +83.791 which is
RA(J2000) = 01h 35m 09s
Dec(J2000) = +83d 47' 27"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The available BAT light curve (up to T+8s)
showed a complex structure with a duration of at least 12 sec.
The peak count rate was ~50,000 counts/sec (15-350 keV),
at ~0 sec after the trigger.
The XRT began observing the field at 01:49:10 UT, 90.2 seconds after
the BAT trigger. Using promptly downlinked data we find an
uncatalogued X-ray source with an enhanced position: RA, Dec 23.8113,
83.7912 which is equivalent to:
RA(J2000) = 01h 35m 14.7s
Dec(J2000) = +83d 47' 28"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 9 arcseconds from the BAT onboard position. This position
may be improved as more data are received; the latest position is
available at https://www.swift.ac.uk/sper.
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 860 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of
the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag.
The 8'x8' region for the list of sources generated on-board covers 100% of the
BAT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.157.
Burst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)
GCN Circular 34939
Subject
GRB231104A: LCOGT Optical Upper Limits
Date
2023-11-04T04:09:15Z (2 years ago)
From
Robert Strausbaugh at Eastern Illinois University <rstrausbaugh@eiu.edu>
Via
email
R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration:
We observed the Fermi GRB 231104A field (Fermi GBM team, GCN 34937) with the LCOGT 1-meter Sinistro instrument at the McDonald Observatory, USA site, on November 4, from 02:53 to 03:25 UT (corresponding to 1.10 to 1.63 hours from the GRB trigger time) with the SDSS r and i filters.
We performed a series of 3x300s exposures in each band. We do not detect a source within the Swift-XRT error region around the candidate X-ray source (Page et al., GCN 34938) in either band.
The following 5-sigma upper limits are calculated using the PanSTARRS catalog as reference:
r > 22.6
i > 21.8
These magnitudes are not corrected for galactic extinction.
GCN Circular 34940
Subject
GRB 231104A: Enhanced Swift-XRT position
Date
2023-11-04T08:03:51Z (2 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1654 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 231104A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 23.80633, +83.79348 which is equivalent
to:
RA (J2000): 01h 35m 13.52s
Dec (J2000): +83d 47' 36.5"
with an uncertainty of 2.2 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 34941
Subject
GRB 231104A: Swift/UVOT Upper Limits
Date
2023-11-04T12:44:11Z (2 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
Via
email
N. P. M. Kuin (UCL/MSSL) and K. L. Page (U. Leicester) report on behalf
of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 231104A
91 s after the BAT trigger (Page et al., GCN Circ. 34940). No optical
afterglow consistent with the XRT position (Goad et al., GCN Circ. 34940)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 91 241 147 >21.7
u_FC 304 553 246 >20.7
white 91 1709 411 >21.8
v 633 1758 117 >19.3
b 559 1684 117 >20.4
u 304 1659 343 >20.9
w1 683 1808 117 >19.7
m2 659 679 20 >18.6
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.156 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 34943
Subject
GRB 231104A: Fermi-LAT detection
Date
2023-11-04T16:29:52Z (2 years ago)
From
N. Di Lalla at Stanford University <niccolo.dilalla@stanford.edu>
Via
email
G. Principe (University of Trieste), F. Longo (University of Trieste), N. Di Lalla (Stanford University), D. Tak (Seoul National University) report on behalf of the Fermi-LAT Collaboration:
At 01:47:28 on November 04, 2023 Fermi-LAT detected high-energy emission from GRB 231104A, which was also detected by Fermi-GBM (trigger 720755253.13875 / 231104075, GCN 34937) and Swift (GCN 34938).
The best LAT on-ground location is found to be
RA, Dec = 24.1, 84.0 (degrees, J2000)
with an error radius of 0.7 deg (90 % containment, statistical error only). This was 29 deg from the LAT boresight at the time of the trigger.
The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the trigger with high significance. The 100 MeV - 1 GeV photon flux in the time interval 0-400 s after the GBM trigger is (6.6 ± 2.2) E-06 ph/cm2/s.
The estimated integrated photon index above 100 MeV is -2.7 +/- 0.5. The highest-energy photon is a 530 MeV event which is observed 120 seconds after the GBM trigger.
The Fermi-LAT point of contact for this burst is Giacomo Principe (giacomo.principe@ts.infn.it).
The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.
GCN Circular 34944
Subject
GRB 231104A: Swift-XRT refined Analysis
Date
2023-11-04T16:55:30Z (2 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U.
Leicester), M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), V.
D'Elia (SSDC & INAF-OAR), A. Tohuvavohu (U. Toronto), D.N. Burrows
(PSU) and P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 6.6 ks of XRT data for GRB 231104A, from 72 s to 34.5
ks after the BAT trigger. The data comprise 62 s in Windowed Timing
(WT) mode (the first 9 s were taken while Swift was slewing) with the
remainder in Photon Counting (PC) mode.
The late-time light curve (from T0+10.9 ks) can be modelled with a
power-law decay with a decay index of alpha=1.08 (+/-0.22).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.93 (+0.28, -0.27). The
best-fitting absorption column is 7.9 (+1.1, -1.0) x 10^22 cm^-2, in
excess of the Galactic value of 1.3 x 10^21 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 9.9 x 10^-11 (3.0 x 10^-10) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 7.9 (+1.1, -1.0) x 10^22 cm^-2
Galactic foreground: 1.3 x 10^21 cm^-2
Excess significance: 12.5 sigma
Photon index: 1.93 (+0.28, -0.27)
If the light curve continues to decay with a power-law decay index of
1.08, the count rate at T+24 hours will be 0.017 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.7 x
10^-12 (5.0 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01194500.
This circular is an official product of the Swift-XRT team.
GCN Circular 34945
Subject
GRB 231104A: AstroSat CZTI detection
Date
2023-11-04T17:12:40Z (2 years ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>
Via
Web form
P. K. Navaneeth (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 a bright long-duration GRB 231104A which was also detected by Fermi-GBM (Fermi GBM Team, GCN Circ. 34937), and Swift-BAT (Page et al., GCN Circ. 34938).
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2023-11-04 01:47:40.35 UTC. The measured peak count rate associated with the burst is 1905 (+239, -231) counts/s above the background in the combined data of three quadrants (out of four), with a total of 2144 (+214, -227) counts. The local mean background count rate was 232 (+6, -7) counts/s. Using cumulative rates, we measure a T90 of 5 (+1, -1) s. We note that the total count measurements are affected by a 0.3s housekeeping dead time window that coincided with the burst. We also see a faint second peak, consistent with the light curve from Fermi-GBM and Swift-BAT, which is more prominently seen in the Veto detectors as reported below. However, the peak is too weak to make any contribution to the T90 measurements in the CZT lightcurve.
The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2023-11-04 01:47:38.43 UTC. The measured peak count rate associated with the burst is 3448 (+108, -118) counts/s above the background in the combined data of all quadrants, with a total of 14749 (+818, -888) counts. The local mean background count rate was 1357 (+7, -8) counts/s. We measure a T90 of 24 (+1, -18) s from the cumulative Veto light curve. This longer T90 arises from a clear detection of the second peak of the 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.
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb
GCN Circular 34946
Subject
GRB 231104A: AKO Upper Limit
Date
2023-11-04T19:20:58Z (2 years ago)
From
Mohammad Odeh at Al Khatim Observatory M44 <mshodeh@gmail.com>
Via
legacy email
Mohammad Odeh (Al-Khatim Observatory, AKO, operated by the International
Astronomical Center in Abu Dhabi, UAE) and Nidhal Guessoum (American
University of Sharjah, UAE) report:
We observed the Fermi GRB 231104A field (Fermi GBM team, GCN 34937) with
with our 0.36m f/7.7 robotic telescope on November 4, from 17:12 to 18:22
UT (corresponding to 16.6 hours from the GRB trigger time) using (Ic)
filter. We obtained 24x180 second images.
We do not detect a source within the Swift-XRT error region around the
candidate X-ray source (Page et al., GCN 34938).
The following 5-sigma upper limit is calculated using the ATLAS catalog as
reference:
Ic = 19.7
GCN Circular 34950
Subject
GRB 231104A: Fermi GBM Observation
Date
2023-11-05T05:31:07Z (2 years ago)
From
sumanbala2210@gmail.com
Via
Web form
S. Bala (USRA) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 01:47:28.14 UT on 04 November 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 231104A (trigger 720755253/231104075).
which was also detected by Swift BAT (K. L. Page et al. 2023, GCN 34938) and
Fermi LAT (G. Principe. et al. 2023, GCN 34943).
The Fermi GBM on-ground location is consistent with the Swift BAT position.
The angle from the Fermi LAT boresight is 32 degrees.
The GBM light curve Consist of three distinguishable pick with a duration (T90)
of about 44 s (50-300 keV). The time-averaged spectrum
from T0-3.6 to T0+62.0 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.07 +/- 0.01 and the cutoff energy,
parameterized as Epeak, is 539 +/- 22 keV.
The event fluence (10-1000 keV) in this time interval is
(5.59 +/- 0.06)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.6 s in the 10-1000 keV band is 2 +/- 0.2 ph/s/cm^2.
A Band function fits the spectrum equally well
with Epeak= 490 +/- 20 keV, alpha = -1.05 +/- 0.02 and beta = -2.6 +/- 0.2.
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 34951
Subject
GRB 231104A: NOT upper limit
Date
2023-11-05T11:47:50Z (2 years ago)
From
Zipei Zhu at NAOC <zpzhu@nao.cas.cn>
Via
email
Z. Zhu, D. Xu (NAOC), D.B. Malesani (Radboud Univ. and DAWN/NBI), A. de Ugarte Postigo (OCA-CNRS), Z. Gray (NOT) report on behalf of a larger collaboration:
We observed the field of GRB 231104A detected by Swift (Page et al., GCN 34938) and Fermi (Fermi GBM team, GCN 34937) using the the 2.56 m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observations started at 01:57:16 UT on 2023-11-05, i.e., ~ 1.0 day after the Swift/BAT trigger, and 9x200 s Sloan i-filter images were obtained.
No optical source is detected within or at the border of the Swift/XRT enhanced error circle (Goad et al., GCN 34940) down to upper limits of i > 24.2 mag (3-sigma), calibrated with the nearby Pan-STARRS stars and not corrected for Galactic extinction.
GCN Circular 34955
Subject
GRB 231104A: 3.6m DOT optical upper limit
Date
2023-11-06T18:02:21Z (2 years ago)
From
Rahul Gupta at Aryabhatta Research Institute of Observational Sciences (ARIES) India <rahulbhu.c157@gmail.com>
Via
email
Rahul Gupta, Amit K. Ror, Amar Aryan, and S. B. Pandey (ARIES) report on
behalf of a larger collaboration:
We observed the field of GRB 231104A detected by Fermi (Fermi GBM team, GCN
34937; Principe et al., GCN 34943), Swift (Page et al., GCN 34938), and
AstroSat (Navaneeth et al., GCN 34945) using the 3.6m Devasthal Optical
Telescope of ARIES Nainital. We have taken multiple frames having an
exposure time of 100 sec in the r and i filters, respectively. We do not
find any evidence of an afterglow candidate inside the Swift/XRT enhanced
error circle (Goad et al., GCN 34940), consistent with other non-detections
(Strausbaugh et al., GCN 34939; Kuin et al., GCN 34941; Odeh et al., GCN
34946; and Zhu et al., GCN 34951). We obtained the limiting mag of ~ 24 mag
(r-band) at ~ 0.9 days post-detection.
The limiting magnitudes quoted are not corrected for the Galactic
extinction in the direction of the burst. Photometric calibration is
performed using the standard stars from the Pan-STARRS catalog.
This circular may be cited. 3.6m Devasthal Optical Telescope (DOT) is
the recently commissioned facility in the Northern Himalayan region of
India (long:79 41 04E, lat:29 21 40N, alt:2540m) owned and operated by the
Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital (
https://www.aries.res.in). Authors of this GCN circular thankfully
acknowledge consistent support from the staff members to run and maintain
the 3.6m DOT.
GCN Circular 34957
Subject
GRB 231104A: NuSTAR Observation of the prompt emission
Date
2023-11-06T19:21:51Z (2 years ago)
From
Brian Grefenstette at Caltech/NuSTAR <bwgref@srl.caltech.edu>
Via
Web form
B. Grefenstette reports on behalf of the NuSTAR Search for INteresting Gamma-ray Signals (SINGS) working group:
The NuSTAR SINGS working group reports the discovery of prompt emission from a potential GRB 231104A in the NuSTAR CsI anti-coincidence shields and the CdZnTe imagers. This GRB was identified through a blind search using the CsI shield rates. Details of the search algorithm will be described in a future paper.
The CsI data are recorded at 1 Hz and show a broad burst with multiple peaks. The initial NuSTAR trigger had a T0 of 2023-11-04T01:47:31, though offline analysis shows that a initial rise in the shield of 2023-11-04T01:47:37, which is consistent with the onset time reported by Ferm GBM (Bala et al, GCN Circ 34950). Peak 1-sec count rates were ~4,000 counts per second in both the FPMA and FPMB shield units. Typical background rates are ~1,000 counts per second. The burst was detected in both the CdZnTe detectors as well as in the shields.
Using the localization from Swift (Palmer et al, GCN Circ 34938):
RA(J2000) = 01h 35m 09s
Dec(J2000) = +83d 47' 27"
…the burst was ~100-degrees from the instrument boresight.
The main burst lasts for ~6-s. Two narrow (<1-s) peaks can be seen in both the 1-Hz CsI shield rates and in the CdZnTe detectors.
The automated light curve report for this GRB, discovery report, off-line analysis of the shield data, and the CdZnTe lightcurves can be found here:
https://nustarsoc.caltech.edu/NuSTAR_Public/grbs/reports/2023/231104A/
Information on NuSTAR SINGS can be found here:
https://nustarsoc.caltech.edu/NuSTAR_Public/grbs/
NuSTAR is a NASA Small Explorer mission led by Caltech and managed by JPL for NASA’s Science Mission Directorate in Washington.
GCN Circular 34958
Subject
GRB 231104A: Wendelstein Optical/Infrared Observations
Date
2023-11-06T20:45:59Z (2 years ago)
From
m.busmann@physik.lmu.de
Via
Web form
Malte Busmann (LMU), Daniel Gruen (LMU), Brendan O’Connor (CMU), Julius Gassert (LMU), Lei Hu (CMU), Antonella Palmese (CMU), Christoph Ries (LMU), Arno Riffeser (LMU/MPE), Michael Schmidt (LMU), Ananya Shankar (LMU):
We observed the position of GRB 231104A (Fermi GBM team, GCN 34937; Page et al., GCN 34938) with the 2m Fraunhofer telescope at Wendelstein Observatory, Germany. Observations were obtained using the 3kk imager in the r, z, and K bands simultaneously starting on 2023-11-06 at 12:09:53 UT with a total exposure of 6,021 seconds.
At the position of the XRT source (Goad et al., GCN 34940) we do not detect any source within 15” to depth r> 23.6 and K>21.0 AB mag at 2.4 days after the GRB trigger. The magnitudes are not corrected for Milky Way extinction and the photometry was calibrated against nearby stars in the PS1 and 2MASS catalogs.
We thank the staff of the Wendelstein Observatory for obtaining these observations.
GCN Circular 34961
Subject
GRB 231104A: FRAM-ORM optical limit
Date
2023-11-07T13:35:15Z (2 years ago)
From
Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek@asu.cas.cz>
Via
legacy email
Alzbeta Malenakova, Martin Jelinek and Jan Strobl (ASU CAS Ondrejov, CZ),
Sergey Karpov, Martin Masek, Petr Janecek, Jakub Jurysek,
Jan Ebr, Ronan Cunniffe, Petr Travnicek and Michael Prouza
(Institute of Physics, Prague, CZ)
report:
The 25cm robotic telescope FRAM-ORM at La Palma (Spain) reacted robotically
to the Fermi-GBM/Swift/Fermi-LAT/AstroSat CZTI alert of GRB 231104A (Bala
et al., GCNC 34937, Page et al., GCNC 34938 and Goad et al., GCNC 34940,
Principe. et al. 2023, GCNC 34943, Navaneeth et al., GCNC 34945), obtaining
a series of 20s unfiltered images starting at 01:48:10.3 UT, i.e. 31.3s
post trigger, covering the third gamma ray episode of the GRB.
We do not detect any new source in comparison to Atlas Refcat 2.0 (Tonry et
al., 2018) neither in single images (detection limit r'>17.6) nor in a
combined 40x20s frame (mean exp time 960s post trigger, with a limit
r'>18.6) similarly to Strausbaugh et al. (GCNC 34939), Kuin et al. (GCNC
34941), Odeh et al. (GCNC 34946), Zhu et al. (GCNC 34951), Gupta et al.
(GCNC 34955) and Busman et al. (GCNC 34958).
GCN Circular 34964
Subject
GRB 231104A: Swift-BAT refined analysis
Date
2023-11-08T01:28:51Z (2 years ago)
From
Sibasish Laha at GSFC <sibasish.laha@nasa.gov>
Via
email
M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa),C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),
T. Sakamoto (AGU),(i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 231104A (trigger #1194500)
(Page et al., GCN Circ. 34938). The BAT ground-calculated position is
RA, Dec = 23.824, 83.794 deg which is
RA(J2000) = 01h 35m 17.8s
Dec(J2000) = +83d 47' 38.7"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 89%.
The BAT light curve shows a complex structure with a duration of ~ 80 sec.
T90 (15-350 keV) is 46.77 +- 1.54 sec (estimated error including systematics).
The time-averaged spectrum from T-13.39 to T+55.84 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.24 +- 0.03. The fluence in the 15-150 keV band is 1.3 +- 0.0 x 10^-05 erg/cm2.
The 1-sec peak photon flux measured from T+0.24 sec in the 15-150 keV band
is 24.8 +- 0.6 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1194500/BA/
GCN Circular 35008
Subject
GRB 231104A: VZLUSAT-2 detection
Date
2023-11-13T11:04:18Z (2 years ago)
From
Marianna Dafčíková at Masaryk University <500025@mail.muni.cz>
Via
Web form
M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU) -- the VZLUSAT-2/GRB payload collaboration.
The long-duration GRB 231104A (Fermi/GBM detection: GCN 34937; Fermi/LAT detection: GCN 34943; Swift/BAT detection: GCN 34938; AstroSat detection: GCN 34945; NuSTAR detection: GCN 34957; Konus/WIND trigger at 2023-11-04 01:47:39.141 UT, INTEGRAL/SPI-ACS peak detection at 2023-11-04 ~01:47:40 UT) was detected by the GRB detector on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/).
The data acquisition was performed by the GRB detector unit no. 1. The detection was confirmed at the peak time 2023-11-04 01:47:39 UTC. The T90 duration is 26 s and the significance during T90 reaches 21 sigma.
The light curve obtained by VZLUSAT-2 is available here:
https://vzlusat2.konkoly.hu/static/share/GRB231104A_GCN_VZLUSAT2.pdf
All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/hea/VZLUSAT-2/
The GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral.