[vsnet-grb-info 12952] GRB 130310A: optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14289
SUBJECT: GRB 130310A: optical observations
DATE:    13/03/12 08:00:05 GMT
FROM:    Antonino Cucchiara at UCSC/UCO Lick  <acucchia at ucolick.org>

A. Cucchiara (UCSC/UCO Lick Observatory), S. B. Cenko 
(UC Berkeley), D. Perley (Caltech) report on behalf of 
a large collaboration:

"On March 12.4 UT we observed the field of the short-hard 
GRB 130313A (GCN 14282, 14283, 14284, 14285 and 14288) 
with the Gemini-South telescope equipped with the GMOS camera.

We obtained 5x180s exposures, for a total integration time
of 15 minutes (T_mid = T0+1.22 days). 


A snapshot of our imaging campaign can be seen here:
https://www.dropbox.com/s/jqt714c44b7ngei/0310A_rband.jpeg
We note the presence of two irregular objects (marked as "G1" adn "G2") 
within the current XRT error circle (3.6 arcsec radius, GCN 14288).

The coordinates of this objects are:

"G1"
RA: 09:27:36.34  (J2000)
Dec: -17:06:18.92 (J2000)

"G2"
RA: 09:27:36.46  (J2000)
Dec: -17:06:13.80 (J2000)


Using 3 USNO-B1 stars we estimate a preliminary 
brightness for "G1" of r' = 25.05 +- 0.15 and for
"G2" r'=23.80 +- 0.10.

At this point the nature of these objects as well as the relation with 
GRB 130313A afterglow is still uncertain. Further observations
are encouraged.

We thank the Gemini staff for performing this observations,
in particular J. Thomas-Osip"