GRB 240225C
GCN Circular 35799
Subject
GRB 240225C: AstroSat CZTI detection
Date
2024-02-26T09:10:37Z (a year ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar24@gmail.com>
Via
Web form
J. Joshi (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 240225C which was also detected by Calet (Trigger Num. 1392873321), INTEGRAL/SPI-ACS (Trigger Num. 10590), and Konus-WIND (IPN RAW notices).
The source was detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2024-02-25 05:19:38.80 UTC. The measured peak count rate associated with the burst is 289 (+71, -45) counts/s above the background in the combined data of all quadrants, with a total of 1297 (+320, -349) counts. The local mean background count rate was 1387 (+7, -7) counts/s. We measure a T90 of 6.7 (+2.6, -1.6) 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 35802
Subject
GRB 240225C: GRBAlpha detection
Date
2024-02-26T18:27:13Z (a year ago)
From
Jakub Ripa <ripa.jakub@gmail.com>
Via
Web form
J. Ripa, M. Dafcikova, M. Kolar (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, 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.), T. 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 240225C (AstroSat detection: GCN 35799; CALET/CGBM detection: trigger no. 1392873321; INTEGRAL/SPI-ACS detection: trigger no. 10590) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract).
The detection was confirmed at the peak time 2024-02-25 05:19:36.5 UTC. The T90 duration measured by GRBAlpha is 8.5 s and the overall significance during T90 reaches 5.5 sigma.
The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240225C_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 35806
Subject
GRB 240225C: CALET Gamma-Ray Burst Monitor detection
Date
2024-02-26T20:51:06Z (a year ago)
From
Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>
Via
Web form
S. Sugita , A. Yoshida, T. Sakamoto (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 240225C (INTEGRAL SPI ACS Trigger: Trigger Num. 10590;
IPN RAW NOTICE (KONUS/Wind); AstroSat CZTI detection: Joshi et al.,
GCN Circ. 35799; GRBAlpha detection: Ripa et al., GCN Circ. 35802)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 05:19:32.73
UTC on 25 February 2024
(http://cgbm.calet.jp/cgbm_trigger/flight/1392873321/index.html).
The burst signal was seen by all CGBM detectors.
The burst light curve shows a single pulse that starts
at T+2.6 sec, peaks at T+4.2 sec, and ends at T+22.6 sec.
The T90 and T50 durations measured by the SGM data are 13.1 +/- 3.4 sec
and 4.6 +/- 0.4 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1392873321/index.html
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 35846
Subject
GRB 240225C: Glowbug gamma-ray detection
Date
2024-03-02T14:35:03Z (a year ago)
From
C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>
Via
Web form
C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (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 240225C, which was also detected by AstroSat/CZTI (GCN 35799), GRBAlpha (GCN 35802), CALET (GCN 35806), INTEGRAL/SPI-ACS (Trigger 10590), and Konus/Wind (Trig_Time 05:19:33.355).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-02-25 05:19:33.944 with a duration of 13.8 s and a total significance of about 83 sigma. The light curve comprises a single peak.
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=1.5 and a cutoff energy ("Epeak") of 270 keV. The modeled 10-10000 keV fluence is 6.4e-06 erg/cm^2.
The best-fit localization is RA, Decl. (J2000, deg) = 351.0, 25.7 with a radius of 4.2 deg (95% confidence), with a highly uncertain systematic uncertainty.
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
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