TITLE:   GCN CIRCULAR
NUMBER:  44681
SUBJECT: GRB 260225D: TERI Gamma-ray detection
DATE:    26/05/21 14:06:05 GMT
FROM:    nicholasjkirschner@gmail.com

Nicholas Kirschner (a), Daniel Shy (b), C.C. Cheung (b), Bernard Phlips (b), Michael Streicher (c), James Mason (c), Douglas M. Groves (c), Feng Zhang (c), and Willy Kaye (c)   
 
(a) National Research Council Research Associate resident at the U.S. Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375 
(b) U.S. Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375   
(c) 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 260225D, which was also detected
by Glowbug (GCN 43856), Konus-Wind (Trig_Time 19:51:32.84), SVOM/GRM (GCN 43885),
and GRID (GCN 43890).

Using 1 Hz binning and adopting T0 = 2026-02-25T19:51:28.768Z, we observe two peaks at
T0+1.375s and 2.625s and peak excess count rate of 108 and 149 counts per second (cps) above
the 128 cps 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 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 by the Office of Naval
Research 6.1.

[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.