GCN Circular 45762
GRB 260924A: Near-infrared detection with MDM/MIRAGE
From: Geoffrey Mo at Caltech / Carnegie Observatories
Issued: 2026-09-26 17:03 UTC
Type: GRB

Geoffrey Mo (Carnegie/Caltech), K. De, V. Karambelkar, S. Ibrahim, D. Schiminovich (Columbia University) report:

We observed the field of GRB 260924A (Fermi GBM Team, GCN 45712; D'Elia et al., GCN 45713; Evans et al., GCN 45715; Salunke et al., GCN 45720; Holzmann Airasca et al., GCN 45721; McDermott et al., GCN 45723; Dichiara et al., GCN 45730; Waratkar et al., GCN 45732; Gupta et al., GCN 45733; Vijaykumar et al., GCN 45734; Yu et al., GCN 45741; Gupta et al., GCN 45750; Ridnaia et al., GCN 45751) in the near-infrared J and Hs bands with the MDM InfraRed Astronomy inGaas Experiment (MIRAGE) instrument on the MDM 1.3 m telescope.

Observations began at 2026-09-26T12:08:38 (+2.46 days after the GRB trigger) in the J band and 2026-09-26T12:32:07 (+2.47 days) in the Hs band, lasting 1080 s in J and 1050 s in Hs. We detect the optical counterpart (Hu et al., GCN 45717; Izzo et al., GCN 45718; Klingler et al., GCN 45735; Ma et al., GCN 45736; Castro-Tirado et al., GCN 45740; Novotny et al., GCN 45743; Aryan et al., GCN 45748; Li et al., GCN 45758; Fortin et al., GCN 45759) in the J band and set an upper limit in Hs, with the following AB magnitudes: J = 19.81 ± 0.20, Hs > 19.2.

MIRAGE is a new robotic YJHs-band near-infrared imager for the MDM 1.3m telescope. We thank the Mt Cuba Astronomical Foundation for development of MIRAGE and the MDM Observatory staff for supporting the observations.

Filter: gamma-ray bursts are posted only if in the top 10% of the past year's — by fluence (total energy received per cm², from Fermi GBM, Konus-Wind, GECAM and similar circulars; now ≥ 3.9×10^-5 erg/cm²) or by the number of GCN Circulars about the burst (now ≥ 14). Thresholds are recalculated monthly.
Relayed automatically from NASA's General Coordinates Network.