GCN Circular 44590

Subject

GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE

Event

GRB 260509A

Date

2026-05-12T20:45:37Z (3 days ago)

From

Geoffrey Mo at Caltech / Carnegie Observatories <gmo@mit.edu>

Via

Web form

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

We observed the field of GRB 260509A (Gotz et al., GCN 44504

) in the near-infrared J and Hs bands with the MDM InfraRed Astronomy inGaas Explorer (MIRAGE) instrument on the MDM 1.3 m telescope.

Observations began at 2026-05-10T04:00:51 (+6.2 hours after the GRB trigger) in the J band and 2026-05-10T03:27:31 (+5.6 hours) in the Hs band, lasting 1560 s in J and 1260 s in Hs.

The optical counterpart (O’Neill et al., GCN 44505

; Saccardi et al., GCN ; Wu et al., GCN ; Alvarez et al., 44509; Zheng et al., GCN ; Lipunov et al., GCN ; Belkin et al., GCN ; Corcoran et al., GCN ; Bochenek et al., GCN ; Moskvitin et al., GCN ) is detected in the J filter at low significance and undetected in H band, with the following AB magnitudes: J = 20.91 ± 0.40, Hs > 19.6.

MIRAGE is a new YJHs-band near-infrared imager for the MDM 1.3m telescope. We thank the MDM Observatory staff for supporting the observations.