GCN Circular 37232

D. Murphy, C. McKenna, C. de Barra, A. Ulyanov, P. McDermott, M. Doyle, R. Dunwoody, J. Mangan, G. Finneran, L. Cotter, A. Empey, J. Fisher, 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 GRB240821A which was also detected by Fermi GBM (GCN 37219) and SVOM (GCN 37220, GCN 37226). The detection was made at 24-08-21 18:36:03.2 UTC.

The GMOD light curve for GRB240821A, with 1.2s binning shows a single peak. The spacecraft location at time of detection was 21.884 S, 54.418 E and an altitude of 490.5 km.

The light curve for this event as measured by GMOD can be found here: https://grb.eirsat1.ie/20240821A/20240821A_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.