[vsnet-grb-info 11487] GRB 120119A: GRT detection of early afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12894
SUBJECT: GRB 120119A: GRT detection of early afterglow
DATE:    12/01/22 02:16:11 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori.sakamoto-1 at nasa.gov>

T. Sakamoto (UMBC/GSFC), D. Donato (ORAU/GSFC), N. Gehrels (GSFC),
T. Okajima (GSFC), Y. Urata (NCU)

We observed the field of GRB 120119A detected by Swift
(trigger #512035; Beardmore et al., GCN Circ. 12859) with the 14-inch
Goddard Robotic Telescope (GRT) located at the Goddard Geophysical
and Astronomical Observatory (http://cddisa.gsfc.nasa.gov/ggao/).

A total 294 images of 5 sec (200 images), 30 sec (60 images) and 
60 sec (34 images) exposures were taken in the R filter starting 
from January 19 04:06:42 (UT), about 132 seconds after the trigger 
(114 seconds after the BAT position notice), and stopped on 
January 19 06:07:50 (UT).  

We detect the optical afterglow inside the XRT error circle (Beardmore 
et al., GCN Circ. 12876) in the stacked image of good quality 5 sec 
exposure images (total exposure of 985 sec).  The estimated magnitude is 
R = 17.24 +- 0.19 mag (start time: 04:06:42, stop time: 04:44:37).   We do 
not detected the afterglow in the stacked images of 30 sec exposure images 
(total exposure of 1560 sec) and 60 sec exposure images (total exposure of 
2040 sec).  The estimated five sigma upper limits of those stacked images 
are ~17.9 mag (start time: 04:44:55, stop time: 05:30:01) and ~18.0 mag 
(start time: 05:30:17, stop time: 06:07:50).  All the reported magnitudes 
are estimated using the USNO-B1 catalog.