TITLE: GCN CIRCULAR NUMBER: 39092 SUBJECT: Ep250125A: 1.3m DFOT optical upper limit DATE: 25/01/30 05:24:36 GMT FROM: ANSHIKA GUPTA at ARIES anshika05180@gmail.com
Anshika Gupta, Amit K. Ror, Divyanshu, Kuntal Mishra, and Shashi B. Pandey (ARIES) report:
We observed the field of Ep250125A detected by EP-WXT trigger ( Wu et al. 2025, GCN 39028) with the 1.3m Devasthal Fast Optical Telescope (DFOT), located at the Devasthal Observatory of the Aryabhatta Research Institute of Observational Sciences (ARIES), India. The observations were started on 2025-01-25 at 22:27:28 UT, i.e., ~ 19.83 hours after the EP-WXT trigger. We have taken multiple frames with an exposure time of 300 s in the R filter. We stacked the images after the alignment. We could not detect the optical emission in our stacked image within the error box of the EP-WXT telescope (Wu et al. 2025, GCN 39028) and Swift-XRT (Kennea et al. 2025, GCN 39029). We obtain the following 3-sigma upper limit in the stacked image:
Date Start_UT T_start-T0 (hour) Filter Exp time (s) Magnitude ========================================================= 2025-01-25 22:27:28 ~19.83 R 300s*24 >22.8
The non-detection of the burst is consistent with the upper limits reported by Aryan et al. 2025, GCN 39032.
The magnitude is not corrected for the Galactic extinction in the direction of the burst. Photometric calibration is performed using the standard stars from the USNO-B1.0 catalogue. This circular may be cited.
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