GRB 231018A
GCN Circular 34873
Subject
GRB 231018A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
Date
2023-10-23T18:21:25Z (2 years ago)
From
GAYATHRI RAMAN at PSU <gzr5209@psu.edu>
Via
Web form
Tyler Parsotan (NASA GSFC), Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU), Samuele Ronchini (PSU), James DeLaunay (U Alabama), Jamie A. Kennea (PSU) report:
Swift/BAT did not localize GRB 231018A onboard (T0: 2023-10-18T12:30:10.66 UTC, Fermi trig 719325015-GCN#34826, CALET trigger 1381667434-GCN#34849)
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 90 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), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 109.13 in a 16 s analysis time bin, starting at T0 - 12 s. The burst has a multi-peak structure with a duration of ~30 s in the BAT rates curve.
NITRATES results are consistent with a burst coming from outside the FOV, with DeltaLLHOut of -578.9.
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 34865
Subject
GRB 231018A: VZLUSAT-2 detection
Date
2023-10-21T09:42:35Z (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 231018A (Fermi/GBM detection: GCN 34831; Konus/Wind detection: GCN 34846; Glowbug detection: GCN 34847; CALET/CGBM detection: GCN 34849; GRBAlpha detection: GCN 34850; INTEGRAL/SPI-ACS peak detection at 2023-10-18 ~12:31:08 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 2023-10-18 12:31:10 UTC. The T90 duration is 41 s and the significance during T90 reaches 25 sigma.
The light curve obtained by VZLUSAT-2 is available here:
https://vzlusat2.konkoly.hu/static/share/GRB231018A_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.
GCN Circular 34850
Subject
GRB 231018A: GRBAlpha detection
Date
2023-10-20T10:02:38Z (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, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), yyT. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.
The long-duration GRB 231018A (Fermi/GBM detection: GCN 34831; Konus/Wind detection: GCN 34846; Glowbug detection: GCN 34847; CALET/CGBM detection: GCN 34849; INTEGRAL/SPI-ACS peak detection at 2023-10-18 ~12:31:08 UT) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; arXiv:2302.10048).
The detection was confirmed at the peak time 2023-10-18 12:31:08 UTC. The T90 duration measured by GRBAlpha is 32 s and the overall significance during T90 reaches 91 sigma.
The light curve obtained by GRBAlpha is available here:
https://grbalpha.konkoly.hu/static/share/GRB231018A_GCN.pdf
All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume.
GCN Circular 34849
Subject
GRB 231018A: CALET Gamma-Ray Burst Monitor detection
Date
2023-10-20T04:35:30Z (2 years ago)
From
Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>
Via
Web form
P. S. Marrocchesi (U of Siena), 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),
and the CALET collaboration:
The long GRB 231018A (Fermi GBM Final Real-time Localization: Fermi
GBM team, GCN Circ. 34826; BALROG localization: Preis et al.,
GCN Circ 34827; Fermi GBM Detection: Lesage et al., GCN Circ 34831;
IPN triangulation: Svinkin et al., GCN Circ 34845; Konus-Wind detection:
Frederiks et al., GCN Circ 34846; Glowbug gamma-ray detection: Cheung
et al., GCN Circ 34847) triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 12:30:52.87 UTC on 18 October 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1381667434/index.html).
The burst signal was seen by only the SGM detector.
The burst light curve shows a multi-peaked structure that ends T+46 sec.
Since CGBM was in the HV-on sequence, the whole episode was not observed by CGBM.
The ground-processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1381667434/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 34847
Subject
GRB 231018A: Glowbug gamma-ray detection
Date
2023-10-19T21:07:59Z (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 231018A, which was also detected by Fermi/GBM, Konus-Wind, CALET, GECAM-B, INTEGRAL/SPI-ACS, and Swift/BAT, resulting in an IPN localization (GCN 34826, 34845, 34846).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2023-10-18 12:30:07.824 with a duration of 87.6 s and a total significance of about 159 sigma. The Glowbug light curve comprises multiple peaks and is generally similar to the Konus-Wind light curve (GCN 34846).
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=1.0 and a cutoff energy ("Epeak") of 193 keV. The modeled 10-10000 keV fluence is 3.4e-05 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 34846
Subject
Konus-Wind detection of GRB 231018A
Date
2023-10-19T18:44:04Z (2 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
Via
legacy email
D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,
Yu. Temiraev, A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The long, bright GRB 231018A (Fermi GBM detection: Lesage et al., GCN 34831;
IPN triangulation: Svinkin et al., GCN 34845)
triggered Konus-Wind (KW) at T0=45043.083 s UT (12:30:43.083).
The burst light curve shows a multi-peaked emission complex,
which starts at ~T0-32 s, peaks at ~T0+28 s,
and has a total duration of ~90 s.
The emission is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB231018_T45043/
As observed by Konus-Wind, the burst had
a fluence of (1.17 ± 0.04)x10^-4 erg/cm^2 and
a 64-ms peak energy flux, measured from T0 + 28.352 s,
of (2.44 ± 0.10)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum (measured from T0 to T0+38.912 s)
is best fit in the 20 keV - 15 MeV range
by a GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.34 (-0.05,+0.05),
the high energy photon index beta = -2.92 (-0.17,+0.12),
the peak energy Ep = 114 (-4,+4) keV,
chi2 = 90/96 dof.
The spectrum near the peak count rate (measured from T0+24.576 to T0+29.696 s)
is best fit in the 20 keV - 15 MeV range
by a GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.19 (-0.05,+0.06),
the high energy photon index beta = -3.15 (-0.37,+0.24),
the peak energy Ep = 146 (-7,+8) keV,
chi2 = 67/73 dof.
All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.
GCN Circular 34845
Subject
IPN triangulation of GRB 231018A
Date
2023-10-19T18:41:19Z (2 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
legacy email
D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia,
and T. Cline on behalf of the Konus-Wind team,
A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,
E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team,
report:
The bright, long-duration GRB 231018A
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 34826