GCN Circular 41636
Subject
EP250827b: FTW Observations of AT 2025wkm
Event
Date
2025-09-01T19:30:16Z (2 months ago)
From
xjh@andrew.cmu.edu
Via
Web form
Xander J. Hall (Carnegie Mellon U.), Malte Busmann (LMU), Daniel Gruen (LMU), Brendan O’Connor (Carnegie Mellon U.), Antonella Palmese (Carnegie Mellon U.), Mansi Kasliwal (Caltech), Tomas Ahumada (Caltech), and Gokul Srinivasaragavan (UMD) report:
We observed the localization of the X-ray flare EP250827b and optical transient AT 2025wkm as reported by Schroeder et al. (GCN 41635), with the Three Channel Imager (3KK) at the Fraunhofer Telescope at Wendelstein Observatory (FTW) in the r, i, and J bands starting at 2025-08-31T02:01:59 UTC (3.82 days after the X-ray flare) for 24 x 180s. In the difference imaging with templates from PS1, we detect AT 2025wkm at
r = 20.14 +/- 0.02 AB mag,
The magnitudes are calibrated against the PS1 catalog and not corrected for Galactic extinction.
Furthermore, we see no other candidates in the difference imaging to a limiting depth of r = 23.15, which supports the association of AT 2025wkn and EP250827b. Further analysis is underway.
We thank Michael Schmidt from the Wendelstein Observatory staff for obtaining these observations.