TITLE:   GCN CIRCULAR
NUMBER:  46055
SUBJECT:  EP 261025a: J-band upper limit with MIRAGE
DATE:    26/10/27 04:30:30 GMT
FROM:    Stella Lucine Manyan <sld2197@columbia.edu>

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 EP261025a (Yang et al., GCN 46025, Mandarakas et al., GCN 46026; Mohan et al., GCN 46028) in the near-infrared J band with the MDM InfraRed Astronomy inGaas Experiment (MIRAGE) instrument on the MDM 1.3 m telescope.

Observations began at UT 2026-10-26T02:49:34 (28.2 hours after EP-WXT trigger) in the J band for a total exposure time of 3210s.

We do not detect any new source within the FXT localization error circle (Yang et al., GCN 46025). We obtain the following 5-sigma upper limit in AB magnitudes: J > 19.8 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.