[vsnet-grb-info 11855] GRB 120422A: Gemini observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13245
SUBJECT: GRB 120422A: Gemini observations
DATE:    12/04/22 10:44:59 GMT
FROM:    Antonino Cucchiara at UCSC/UCO Lick  <acucchia at ucolick.org>

A. Cucchiara (UCSC/UCO Lick), A. Levan (U Warwick), D. B. Fox (PennState),
N. R. Tanvir (U. Leicester) report on behalf of a larger collaboration reports:

On April 22.33 UT (~50 minutes after the BAT trigger) we observed the field 
of GRB 120422A (Troja et al., GCN 13243) using GMOS Spectrograph on 
the Gemini-North 8-m telescope.  

In our acquisition image of 240s in i' band an optical candidate was identified at:

RA: 09:07:38.38
Dec: +14:01:07.5

with an uncertainty of 0.3" in each direction.
Using three SDSS stars in the field we estimate a magnitude of 

i'=19.03 +- 0.15 

We also noticed just outside the XRT error circle the presence of 
the SDSS (DR8) galaxy SDSS J090738.51+140108.3.

A subsequent spectrum of 2x900s, covering the wavelength range 6000-10000 
does not present evident absorption features. 
If the SDSS galaxy is associated with GRB 120422A then its brightness would 
suggest a moderately low redshift (z<1).
Further analysis is in progress.

We thank the Gemini-North staff for their prompt support.