TITLE: GCN CIRCULAR NUMBER: 42177 SUBJECT: GRB 250919A: TERI gamma-ray detection DATE: 25/10/09 21:09:21 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 250919A, which was also detected by Fermi/GBM, SVOM/GRM, EP/WXT, NuSTAR, Glowbug, Insight-HXMT, and Konus-Wind (Fermi GBM team, GCN 41874; Wang et al., GCN 41882; Liang et al., GCN 41879; Waratkar & Grefenstette, GCN 41888; Cheung et al., GCN 41891, Wang et al., GCN 41900; Frederiks et al., GCN 41905) Using 1 Hz binning, and adopting T0 = 2025-09-19 00:28:52.28, we observe the three dominant peaks seen in the Fermi/GBM lightcurve (GCN 41874) at ~T0+24s, ~T0+26s, and ~T0+29s with respective peak excess count rates of roughly 57, 171, and 104 counts per second (cps) above the 27-cps baseline rate observed in nearby off-source intervals. We do not observe the fainter, leading feature at ~T0, as seen in the Fermi/GBM lightcurve. 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 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. [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/42177. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...