GCN Circular 41652
K. De (Columbia/CCA), S. Ibrahim (Columbia), T. Suen (Columbia), M. Sitaram (Columbia), D. Schiminovich (Columbia), G. Mo (Caltech/Carnegie), K. Shin (Caltech)
We observed the field of the X-ray transient EP250828a (Liu et al., GCN 41574; Aryan et al., GCN 41579; Taguchi et al., GCN 41582; Yao et al., GCN 41583; Fu et al., GCN 41584; Zheng et al., GCN 41586; Lipunov et al., GCN 41588; Bochenek et al., GCN 41590; Aryan et al., GCN 41591; Ni et al., GCN 41592) during commissioning operations of the MDM InfraRed Astronomy inGaas Explorer (MIRAGE) instrument on the MDM 1.3m telescope. Observations were carried out starting at UTC 2025-08-28 10:59:08, starting ~ 3.4 hours after the time of the X-ray detection.
We obtained a series of dithered exposures in Y-band amounting to a total exposure time of 850 s. Images were aligned, stacked and calibrated to the PS1 catalog. Performing forced photometry at the position of the X-ray and optical counterpart reported in GCN 41582, 41583, 41591, 41592, we do not detect a point source to a 5 sigma limiting magnitude of > 19.1 AB mag. Analysis will be improved as further commissioning data is processed.
MIRAGE is a new YJH-band near-infrared imager for the MDM 1.3m telescope. We thank the MDM Observatory staff for supporting the commissioning observations.