GRB 231127A
GCN Circular 35197
Subject
GRB 231127A: AstroSat CZTI detection
Date
2023-11-27T11:28:01Z (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-duration GRB 231127A which was also detected by CALET (Trigger Num. 1385097164).
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2023-11-27 05:14:21.75 UTC. The measured peak count rate associated with the burst is 433 (+159, -60) counts/s above the background in the combined data of all quadrants, with a total of 571 (+157, -130) counts. The local mean background count rate was 325 (+7, -11) counts/s. Using cumulative rates, we measure a T90 of 3.0 (+1.4, -0.8) s.
The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2023-11-27 05:14:21.69 UTC. The measured peak count rate associated with the burst is 822 (+78, -76) counts/s above the background in the combined data of all quadrants, with a total of 2145 (+310, -342) counts. The local mean background count rate was 1452 (+11, -12) counts/s. We measure a T90 of 5 (+2, -3) s from the cumulative Veto light curve. We note that this T90 measurement has higher uncertainty due to the intrinsic 1 s binning of Veto data.
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 35200
Subject
GRB 231127A: CALET Gamma-Ray Burst Monitor detection
Date
2023-11-27T15:08:54Z (2 years ago)
From
Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>
Via
Web form
GRB 231127A: CALET Gamma-Ray Burst Monitor detection
K. Kobayashi (Waseda U), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA),
Y. Asaoka (ICRR), S. Torii, Y. Akaike (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 231127A (AstroSat CZTI detection: Navaneeth et al.,
GCN Circ 35197) triggered the CALET Gamma-ray Burst Monitor
(CGBM) at 05:14:16.39 UTC on 27 November 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1385097164/index.html).
The burst signal was seen by all CGBM detectors.
The burst light curve shows a single pulse that starts
at T+2.9 sec, peaks at T+5.4 sec, and ends at T+8.1 sec.
The T90 and T50 durations measured by the SGM data are
4.0 +/- 0.4 sec and 1.4 +/- 0.1 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1385097164/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 35224
Subject
GRB 231127A: GRBAlpha detection
Date
2023-11-29T22:31:48Z (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, L. Szakszonova, 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 231127A (AstroSat detection: GCN 35197; CALET/CGBM detection: GCN 35200; Konus/Wind trigger at 2023-11-27 05:14:24.085 UT; INTEGRAL/SPI-ACS peak detection at 2023-11-27 ~05:14:20 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 2023-11-27 05:14:21 UTC. The T90 duration measured by GRBAlpha is 6 s and the overall significance during T90 reaches 14 sigma.
The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB231127A_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.