GCN Circular 39989

D. Murphy, J. Fisher, C. de Barra, P. McDermott, C. McKenna, A. Ulyanov, G. Finneran, G. Corcoran, L. Cotter, A. Empey, F. Gibson Kiely, J. Thompson, D. McKeown, A. Martin-Carrillo, L. Hanlon, S. McBreen, on behalf of the EIRSAT-1 team:

EIRSAT-1 reports the detection of the short gamma-ray burst GRB 250330B by the Gamma-ray Module (GMOD) instrument, which was also detected by Fermi GBM (GCN 39951). The GMOD detection was made starting at 2025-03-30 21:52:22.4 UTC.

The GMOD light curve for GRB250330B, with 1.2s binning, shows a single peak, consistent with the detection by Fermi GBM.

The spacecraft location at time of detection was 1.704 S, 7.769 E and an altitude of 407.7 km.

The light curve for this event as measured by GMOD can be found here: https://grb.eirsat1.ie/250330B/250330B_LC_onboard_preliminary.png

EIRSAT-1 is Ireland’s first satellite (Doyle et al. Proceedings of the 4th SSEA, 2022). It is a 2U CubeSat and carries onboard a number of experiments including the Gamma-Ray Module (GMOD), a novel, compact, gamma-ray detector (Murphy et al, Experimental Astronomy, 53, 961–990, 2022). GMOD consists of a 25 mm × 25 mm × 40 mm Cerium Bromide scintillator coupled to SiPMs and is designed to detect gamma-ray bursts in the ~ 60 keV - 1.5 MeV range. EIRSAT-1 was developed in University College Dublin with support from ESA’s Fly Your Satellite! programme and was launched on 1st December 2023.