GCN Circular 40135
Subject
GRB 250407A: Continued KAIT/Nickel optical observations
Event
Date
2025-04-11T07:26:26Z (a year ago)
From
Weikang Zheng at UC Berkeley <weikang@berkeley.edu>
Via
email
Asia deGraw, Gracelynn Jost, WeiKang Zheng and Alexei V. Filippenko
(UC Berkeley) report on behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, continued the observation of GRB 250407A optical
afterglow (Zheng et al., GCN 40116; Ducoin et. al, GCN 40117;
Pérez-Fournon et. al, GCN 40125; Pankov et al., GCN 40133) at
03:35 UT, Apr. 09, namely ~1.55 days after burst. A set of clear
(roughly R) filter images were obtained. Compared to our earlier
observations (Zheng et al., GCN 40116), the reported afterglow had
faded to ~20.8 +/- 0.3 mag (Vega) measured in our coadd image.
Additional R band images with 600sx5 exposure were obtained with the
1-m Nickel telescopes located at Lick observatory, starting at ~1.55
days after burst. We measure the brightness of R ~ 21.0 +/- 0.2 mag
(Vega), similar to the R band magnitude reported by Pankov et al.
(GCN 40133) at a slightly later epoch (1.98 days), suggesting that
this might be the host galaxy of GRB 250407A as suggested by Ducoin
et. al, GCN 40117).