TITLE: GCN CIRCULAR NUMBER: 45297 SUBJECT: GRB 260709A: cubesat Avion detection DATE: 26/08/06 08:49:20 GMT FROM: Andrey Bogomolov at Moscow State University <aabboogg@srd.sinp.msu.ru> From Andrey Bogomolov at Moscow State University <aabboogg@srd.sinp.msu.ru> At 2026-07-09 ~01:07:32 UT the long-duration GRB 260709A (Fermi/GBM detection: GCN #45121, GECAM-B detection: GCN #45136, SVOM/GRM detection: GCN #45137, AstroSat detection: GCN #45164) was detected by the DeCoR-1 and DeCoR-3 instruments on the cubesat Avion of the Moscow University project “Sozvezdie-270” [1]. Total amount of photons detected by Avion is 100 (energy band >40 keV), it corresponds to a fluence of ~4.5*10^(-7) erg/cm^2 in the range 40-500 keV. LC in the energy range of 40-500 keV consists of several peaks of various intensity, a maximum flux is ~2 phot/(cm^2*s) at the central peak at 01:07:32 UT. А total duration (T90) of the burst is ~18 s. The light curve obtained by Avion is available here: https://swx.sinp.msu.ru/models/grb_cat/data/pictures/GRB260709A_LC_Avion.png Parameters of GRB 260709A as well as other GRBs detected by Moscow University cubesats are listed at: https://swx.sinp.msu.ru/models/grb_cat/grb.php?lang=en Avion is one of 5 cubesats of the Moscow University project “Sozvezdie-270” [1] launched on 2023 June 27. The payload of Avion is a set of scintillation gamma-ray detectors DeCoR [2], the energy range is >30 keV, the time resolution is 0.5s. [1] Svertilov et al. 2023 https://link.springer.com/chapter/10.1007/978-3-031-50248-4_21 [2] Bogomolov et al. 2026 Cosmic Research 64, 262 https://link.springer.com/article/10.1134/S0010952526600071 View this GCN Circular online at https://gcn.nasa.gov/circulars/45297. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...