GRB 231028A
GCN Circular 34893
Subject
GRB 231028A: Fermi GBM Final Real-time Localization
Date
2023-10-28T04:19:34Z (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 04:09:06 UT on 28 Oct 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 231028A (trigger 720158951.657448 / 231028173).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 214.3, Dec = 21.8 (J2000 degrees, equivalent to J2000 14h 17m, 21d 48'), with a statistical uncertainty of 1.0 degrees.
The angle from the Fermi LAT boresight is 23.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231028173/quicklook/glg_skymap_all_bn231028173.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/bn231028173/quicklook/glg_healpix_all_bn231028173.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231028173/quicklook/glg_lc_medres34_bn231028173.gif
GCN Circular 34894
Subject
GRB 231028A: Swift detection of a burst
Date
2023-10-28T04:28:17Z (2 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
Via
email
M. A. Williams (PSU), S. Dichiara (PSU), D. M. Palmer (LANL),
T. Sakamoto (AGU) and B. Sbarufatti (INAF-OAB) report on behalf of the
Neil Gehrels Swift Observatory Team:
At 04:09:09 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 231028A (trigger=1193078). Swift did not slew to the
GRB location due to an observing constraint.
The BAT on-board calculated location is
RA, Dec 214.029, +20.895 which is
RA(J2000) = 14h 16m 07s
Dec(J2000) = +20d 53' 42"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a complex peak
structure with a duration of at least 18 sec, although the immediately
available data is truncated at T+8s due to packet loss. The peak count
rate was ~8500 counts/sec (15-350 keV), at ~1 sec after the trigger.
Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 15:45 UT on 2023 November 22. There will thus be no XRT
or UVOT data for this trigger before this time.
Swift Triggers have recently been re-enabled while we are dealing
with attitude problems that can lead to star tracker Loss-of-Lock (LoL).
We are confident that this GRB was not caused by an LoL event because:
1) The Swift_BAT_Position notice did not indicate a LoL.
(See the comments section.)
2) This burst location was not near to a known bright source.
3) There was a simultaneous trigger by Fermi-GBM.
4) This is a rate-triggered burst on a 1.024 s timescale, while most LoL
false triggers have been 'Image Triggers' with duration 64 s and longer.
Observers should continue to be cautious (especially checking the
comments for LoL) in future GCN notices going forward.
Burst Advocate for this burst is M. A. Williams (mjw6837 AT psu.edu).
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 34897
Subject
Swift GRB 231028A: Global MASTER-Net observations report
Date
2023-10-28T22:40:30Z (2 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
legacy email
V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik, D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),
D. Buckley
(South African Astronomical Observatory),
O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)
MASTER-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB 231028A ( M. A. Williams et al., GCN 34894) errorbox 39827 sec after notice time and 39846 sec after trigger time at 2023-10-28 15:13:16 UT, with upper limit up to 14.5 mag. Observations started at twilight. The observations began at zenith distance = 78 deg. The sun altitude is -12.3 deg.
MASTER-Tunka robotic telescope located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the Swift GRB 231028A errorbox 65649 sec after notice time and 65669 sec after trigger time at 2023-10-28 22:23:38 UT, with upper limit up to 16.0 mag. Observations started at twilight. The observations began at zenith distance = 79 deg. The sun altitude is -14.4 deg.
The galactic latitude b = 69 deg., longitude l = 20 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2291906
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
39937 | MASTER-Kislovodsk | C | 180 | 13.6 |
40139 | MASTER-Kislovodsk | C | 180 | 13.0 |
40340 | MASTER-Kislovodsk | C | 180 | 14.5 |
41732 | MASTER-Kislovodsk | C | 180 | 13.0 |
65699 | MASTER-Tunka | C | 60 | 16.0 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 34899
Subject
GRB 231028A: Fermi GBM Detection
Date
2023-10-28T22:45:43Z (2 years ago)
From
Peter Veres at University of Alabama in Huntsville <veresp@gmail.com>
Via
Web form
P. Veres (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 04:09:06.66 UT on 28 October 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 231028A (trigger 720158951/231028173),
which was also detected by the Swift/BAT (Williams et al. 2023, GCN 34894).
The Fermi GBM Final Real-time Localization (GCN 34893) is consistent with the Swift position.
The GBM light curve consists of multiple peaks with a duration (T90)
of about 34.8 s (50-300 keV). The time-averaged spectrum
from T0-4.1 to T0+43.0 s is best fit by
a Band function with Epeak = 157 +/- 11 keV,
alpha = -0.72 +/- 0.06, and beta = -2.13 +/- 0.08.
The event fluence (10-1000 keV) in this time interval is
(1.95 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+4.0 s in the 10-1000 keV band is 14.8 +/- 0.4 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 34900
Subject
GRB 231028A: Glowbug gamma-ray detection
Date
2023-10-29T03:45:23Z (2 years ago)
From
J. Eric Grove at U.S. Naval Research Laboratory <eric.grove@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 231028A, which was also detected by Fermi/GBM (GCN 34893, 34899) and Swift/BAT (GCN 34894).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2023-10-28 04:09:01.344 with a duration of 47.1 s and a total significance of about 91.2 sigma. The light curve comprises a structured main peak with at least two following peaks.
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=1.9 and a cutoff energy ("Epeak") of 198 keV. The modeled 10-10000 keV fluence is 9.8e-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 34901
Subject
GRB 231028A: AstroSat CZTI detection
Date
2023-10-29T03:47:02Z (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 long GRB 231028A which was also detected by Fermi-GBM (Fermi GBM Team, GCN Circ. 34893, Veres et al., GCN Circ. 34899), Swift-BAT (Williams et al., GCN Circ. 34894), and Glowbug (Kerr et al., GCN Circ. 34900).
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2023-10-28 04:09:14.25 UTC. The measured peak count rate associated with the burst is 66 (+42, -4) counts/s above the background in the combined data of two quadrants (out of four), with a total of 273 (+88, -85) counts. The local mean background count rate was 156 (+1, -4) counts/s. Using cumulative rates, we measure a T90 of 7.8 (+0.9, -3.0) s. We caution that there was a 0.3 s readout dead time in CZTI after the detection of the burst. Hence, the T90 can be as large as 8.7 s for this GRB, with a lower limit of 4.8 s as estimated above by cumulative rates.
The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2023-10-28 04:09:13.77 UTC. The measured peak count rate associated with the burst is 605 (+74, -72) counts/s above the background in the combined data of all quadrants, with a total of 2924 (+529, -560) counts. The local mean background count rate was 1508 (+6, -7) counts/s. We measure a T90 of 6.2 (+2.3, -1.3) s from the cumulative Veto light curve.
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 34909
Subject
GRB 231028A: CALET Gamma-Ray Burst Monitor detection
Date
2023-10-30T04:07:26Z (2 years ago)
From
Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>
Via
Web form
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), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The long GRB 231028A (Fermi GBM Final Real-time Localization:
Fermi GBM team, GCN Circ. 34893; Swift detection: Williams et al.,
GCN Circ. 34894; Fermi GBM Detection: Veres et al., GCN Circ. 34899;
Glowbug gamma-ray detection: Kerr et al., GCN Circ. 34900;
AstroSat CZTI detection: Navaneeth et al., GCN Circ. 34901)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 04:09:04.43
UTC on 28 October 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1382501309/index.html).
The burst signal was seen by all CGBM detectors.
The burst light curve shows a multi-peaked structure that starts
at T+0.25 sec, peaks at T+6.5 sec, and ends at T+47.5 sec.
The T90 and T50 durations measured by the SGM data are 36.1 +/- 1.2 sec
and 6.9 +/- 1.1 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1382501309/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 34914
Subject
GRB 231028A: Swift-BAT refined analysis
Date
2023-10-30T17:03:43Z (2 years ago)
From
Tyler Parsotan at NASA GSFC <tyler.parsotan@nasa.gov>
Via
email
H. A. Krimm (NSF), S. D. Barthelmy (GSFC),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 231028A (trigger #1193078)
(Williams et al., GCN Circ. 34894). The BAT ground-calculated position is
RA, Dec = 214.016, 20.897 deg which is
RA(J2000) = 14h 16m 03.8s
Dec(J2000) = +20d 53' 47.8"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 68%.
The mask-weighted lightcurve shows a broad initial pulse with subsequent
extended emission.
T90 (15-350 keV) is 37.23 +- 0.98 sec (estimated error including systematics).
The time-averaged spectrum from T-6.86 to T+41.95 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.40 +- 0.04. The fluence in the 15-150 keV band is 7.2 +- 0.2 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+1.06 sec in the 15-150 keV band
is 8.6 +- 0.4 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/1193078/BA/