GCN Circular 12205
Subject
GRB 110726A: ROTSE-III refined analysis, fast decay in early phase
Date
2011-07-27T00:49:50Z (13 years ago)
From
Weikang Zheng at U.of Michigan <zwk@umich.edu>
W. Zheng (U Mich), B. E. Schaefer (Louisiana State), H. Flewelling
(IfA/Hawaii), report on behalf of the ROTSE collaboration:
Further analysis to the early optical observations of GRB 110726A from
ROTSE-IIId (Schaefer et al. GCN 12197) shows that, the OT decayed
quickly in early time after ~140s. The OT is detected in our first
co-added of 10 images (14s -142s) with magnitude ~16.1 +/- 0.2. However,
in our second co-added of 10 images (150s - 429s), and afterward
observations, the OT had faded to below our limiting magnitude of ~18.0,
this gives a decay index larger than -1.7, which is much steeper than
the later decay index reported by Melandri et al. (GCN 12198) of ~-0.4
15 minutes after the burst. We summarize the result below:
t_start t_stop mag err detection? number of co-added images
14.0 74.0 16.1 0.3 Yes 5
82.0 142.0 16.1 0.3 Yes 5
150.0 285.0 17.8 - Upper limit 5
293.0 429.0 17.8 - Upper limit 5