TITLE: GCN CIRCULAR NUMBER: 42600 SUBJECT: GRB 250920C: TERI Gamma-ray detection DATE: 25/11/06 15:48:20 GMT FROM: Daniel Shy <danielshy@danielshy.com> Daniel Shy (a), C.C. Cheung (a), Bernard Phlips (a), Michael Streicher (b), James Mason (b), Douglas M. Groves (b), Feng Zhang (b), Willy Kaye (b) (a) U.S. Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375 (b) H3D, Inc., 812 Avis Dr., Ann Arbor, MI 48108, USA The cadmium zinc TElluride Radiation Imager (TERI) gamma-ray telescope [1], operating on the International Space Station, reports the detection of GRB 250920C, which was also detected by Fermi/GBM (GCN 41903, 41917), Swift/BAT (GCN 41904, 41924), SVOM (GCN 41929), and Konus-Wind (GCN 41957). Using 1 Hz binning and adopting T0 = 2025-09-20T15:25:17.06, we observe the three main peaks as seen in the Fermi/GBM lightcurve (GCN 41903) at ~T0+0.5s, ~T0+26.5, and ~T0+36.5s with respective peak excess count rates of roughly 35, 57, and 44 counts per second (cps) above the baseline rate observed in nearby off-source intervals. The analysis results presented here are preliminary and currently lack a detailed response function. TERI is an Office of Naval Research funded technology demonstrator for large-volume pixelated CdZnTe detectors developed, built, and operated by the U.S. Naval Research Laboratory (NRL) in conjunction with H3D, Inc. The pixelated CdZnTe detectors have an energy range of 40 keV to 3 MeV per pixel. It was launched on 2025 April 21 aboard the Department of Defense Space Test Program’s STP-H10 to the ISS. On the ISS, it is located on the SOX external payload facility on the Columbus module. Analysis of TERI data at NRL is supported under contract with NASA as correlative science for the Fermi Gamma-ray Space Telescope. [1] Shy, Daniel, et al. "Development of the cadmium zinc TElluride Radiation Imager." Journal of Astronomical Telescopes, Instruments, and Systems 10.4 (2024): 044009-044009 (arXiv:2408.04559). Distribution Statement A: Approved for public release. Distribution is unlimited. View this GCN Circular online at https://gcn.nasa.gov/circulars/42600. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...