GRB 260430B
GCN Circular 44478
Subject
GRB 260430B: Glowbug gamma-ray detection
Date
2026-05-05T16:06:39Z (9 days 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 [1,2,3], operating on the International Space Station, reports the detection of GRB 260430B, which was also detected by AstroSat/CZTI (GCN 44469) and SVOM/GRM (sb26043004).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2026-04-30 16:04:22.184 with a duration of 49.2 s and a total significance of about 113 sigma. The light curve comprises a complex series of peaks throughout the burst duration.
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 and operated until 2024 April when it was put in safe storage on orbit. Glowbug was removed from storage and resumed operation on 2025 September 12.
[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] Woolf, R.S. et al. 2024, Proc. SPIE, 13151, id. 1315108
Distribution Statement A: Approved for public release. Distribution is unlimited.
GCN Circular 44469
Subject
GRB 260430B: AstroSat CZTI detection of a long burst
Date
2026-05-05T11:53:54Z (9 days ago)
From
Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com>
Via
Web form
Harsha K. H. (IUCAA), S. Salunke (IUCAA), M. Tembhurnikar (IUCAA), A. Goyal (IITB), A. Arya (IITB), G. Waratkar (Caltech/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 260430B.
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2026-04-30 16:04:26.34 UTC. The measured peak count rate associated with the burst is 100 (+32, -10) counts/s above the background in the combined data of three quadrants (out of four), with a total of 1436 (+290, -227) counts. The local mean background count rate was 219 (+1, -2) counts/s. Using cumulative rates, we measure a T90 of 47 (+2, -4) 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 2026-04-30 16:04:22.5 UTC. The measured peak count rate associated with the burst is 417 (+77, -26) counts/s above the background in the combined data of all quadrants, with a total of 6007 (+912, -928) counts. The local mean background count rate was 1271 (+6, -6) counts/s. We measure a T90 of 40 (+11, -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 data products like interactive and downloadable light curves for this GRB can be found at:
https://astrosat.iucaa.in/cift/cift_products/515261050.0/S515261050.0_details.html
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb