GCN Circular 46064
Subject
GRB261026A: Infrared detection with MDM/MIRAGE
Event
Date
2026-10-27T23:02:35Z (4 days ago)
From
Stella Lucine Manyan <sld2197@columbia.edu>
Via
Web form
Stella Manyan (Columbia U), K. De (Columbia U), G. Mo (Caltech/Carnegie), V. Karambelkar (Columbia U), D. Schiminovich (Columbia U) report:
We observed the field of GRB 261026A discovered by SVOM (Goto et al., GCN 46030), also detected by EP-FXT (Jiang et al., GCN 46058) in the near-infrared J and Hs band with the MDM InfraRed Astronomy inGaas Experiment (MIRAGE) instrument on the MDM 1.3m telescope.
A near-infrared counterpart was detected in J band by WINTER (J = 18.55 +/- 0.1 AB mag at T0+12.6 min; Mohan et al., GCN 46041), which faded to 20.28 mag over ~6 hours as reported by the SYSU 80cm infrared telescope (Shi et al., GCN 46047). Several optical detections have also been reported by other facilities (Zheng et al., GCN 46034; Morín-González et al., GCN 46048; Zhao et al., GCN 46056).
Observations began at 2026-10-27T01:31:05 (19.4 hours after SVOM trigger) in the J band lasting 1620 s, and 2026-10-27 02:06:03 (19.9 hours after trigger) in the Hs band lasting 2160 s. We detect a faint infrared source in Hs band at ~ 2.5 sigma significance at Hs = 20.484 ± 0.486 AB mag, while we obtain an upper limit in the J band with J > 19.83 AB mag.
MIRAGE is a new robotic YJHs-band near infrared imager for the MDM 1.3 m telescope. We thank the Mt Cuba astronomical foundation for supporting development of MIRAGE and MDM Observatory staff for supporting the observations