GCN Circular 42787
Subject
EP251118A: 1.3m DFOT optical afterglow detection
Event
Date
2025-11-21T12:03:39Z (a day ago)
From
ANSHIKA GUPTA at ARIES <anshika05180@gmail.com>
Via
Web form
Anshika Gupta, Pankaj Pawar, Debolina Kar, Dhruv Jain, and Kuntal Misra (ARIES) report:
We observed the field of EP251118A detected by the Einstein Probe (Jiang et al. 2025, GCN 42749) 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 2025-11-20 at 20:16:13 UT, i.e., ~ 2.14 days after the Einstein Probe 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 detect the optical counterpart in our stacked image within the error box of NOT (Malesani et al. 2025, GCN 42751). We obtain the following preliminary magnitude in the stacked image:
Date Start_UT T_start-T0 (days) Filter Exp time (s) Magnitude
======================================================================
2025-11-20 20:16:13 ~2.14 R 250s*18 21.15 +/- 0.25
Our detection is consistent with Malesani et al. 2025 (GCN 42751); Belkin et al. 2025 (GCN 42758);Yadav et al. 2025 (GCN 42760); Busmann et al. 2025 (GCN 42763); Francile et al. 2025 (GCN 42767); Rodríguez et al. 2025 (GCN 42773); Li et al. 2025 (GCN 42776); Lee et al. 2025 (GCN 42780); Moskvitin et al. 2025 (GCN 42785).
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 Gaia catalog.