GRB 260705C
GCN Circular 45132
Subject
GRB 260705C: AstroSat CZTI detection
Date
2026-07-10T15:48:52Z (23 days ago)
From
Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com>
Via
Web form
A. Goyal (IITB), A. Arya (IITB), Harsha K. H. (IUCAA), S. Salunke (IUCAA), 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 short GRB 260705C which was also detected by Fermi (GBM Team, GCN Circ. 45082) and Glowbug (Cheung et al., GCN Circ. 45104).
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2026-07-05 13:58:59 UTC. The measured peak count rate associated with the burst is 310 (+130, -113) counts/s above the background in the combined data of two quadrants (out of four), with a total of 48 (+18, -18) counts. The local mean background count rate was 123 (+9, -10) counts/s. We measure a T90 of 0.27 (+0.11, -0.15) s from the cumulative CZT light curve. We note that the burst is relatively weak, hence theT90 measurement has a larger uncertainty than usual.
CZTI data products like interactive and downloadable light curves for this GRB can be found at: https://astrosat.iucaa.in/cift/cift_products/ET20260705T135858/ET20260705T135858_details.html
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 45104
Subject
GRB 260705C: Glowbug gamma-ray detection of a short burst
Date
2026-07-07T15:25:19Z (a month 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 260705C, which was also detected by Fermi/GBM (GCN 45082).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2026-07-05 13:58:57.840 with a duration of 0.26 s and a total significance of about 19.5 sigma. The light curve comprises a single peak.
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 45082
Subject
GRB 260705C: Fermi GBM Final Localization
Date
2026-07-06T00:40:46Z (a month ago)
From
rhamburg@usra.edu
Via
Web form
The Fermi GBM team reports the detection of a likely SHORT GRB
"At 13:58:58.99 UT on 05 July 2026, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 260705C (trigger 804952743/260705583).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 251.67, Dec = 55.55 (J2000 degrees, equivalent to J2000 16h 46m, +55d 32'),
with a statistical uncertainty of 11.60 degrees.
The angle from the Fermi LAT boresight is 21 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705583/quicklook/glg_skymap_all_bn260705583.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705583/quicklook/glg_healpix_all_bn260705583.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705583/quicklook/glg_lc_medres34_bn260705583.gif"