GCN Circular 41355
Subject
GRB 250813B: Ondrejov D50 fast decay
Event
Date
2025-08-14T00:46:58Z (11 days ago)
From
Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek@asu.cas.cz>
Via
email
M. Jelinek, J. Strobl, F. Novotny, R. Hudec (ASU CAS Ondrejov)
report:
Further to our earlier report (GCN 41353), we provide refined photometric
analysis of the optical afterglow of GRB 250813B (Xie et al., GCN 41352).
Our photometry reveals an extremely rapid decay with the afterglow fading
from the initial magnitude of ~14.4 at ~100s post-trigger to near magnitude
20 at 0.03 days (43 minutes) after the trigger. This represents a fade of
approximately 5.6 magnitudes in less than one hour and an average decay
rate of ~1.8.
Potential observers should note the rapid evolution when planning follow-up
observations.