[vsnet-grb-info 14831] GRB 140423A: ROTSE-III Detection of Optical Counterpart

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16145
SUBJECT: GRB 140423A: ROTSE-III Detection of Optical Counterpart
DATE:    14/04/23 10:01:48 GMT
FROM:    Farley V. Ferrante at Southern Methodist U/ROTSE  <fferrante at smu.edu>

F. V. Ferrante (SMU), T. Guver (Istanbul Univ.), H. Flewelling (IfA/Hawaii), R. Kehoe (SMU),
and G. Dhungana (SMU) report on behalf of the ROTSE GRB team:

ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 140423A
(Swift trigger 596901, GCN 16142; Elenin et al., GCN 16143; A. Kaur et al., GCN 16144).
The first image was at 08:32:45.1 UT, 51.5 s after the burst (0.1 s after the GCN notice time).
The unfiltered images are calibrated relative to USNO A2.0. We detect a 14.2 magnitude,
fading source with coordinates:

     13:09:08.08      +49:50:26.5    (J2000), with positional uncertainty of 1" or better

start UT        mag     mlim(of image)
----------------------------------
08:33:39.6     14.2     16.0

This source is not visible in DSS (second epoch), 2MASS or the MPChecker database.

The object decayed from ~14.2 magnitude to ~15.0 magnitude in ~100 seconds.

A jpeg image is available at http://www.rotse.net/images/gsq596901_3b01_img.jpg

Continuing observations are in progress.