GCN Circular 10390

A. N. Morgan, B. E. Cobb,  J. S. Bloom, S. B. Cenko, D. A. Perley, A.
A. Miller, M. Modjaz, C. R. Klein (UC Berkeley), report:

We have imaged the field of the short-hard GRB 100206A (Krimm et al.,
GCN 10376
Not found
 
 
)  with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona.
Observations began at 2010-02-07 02:37:50 UT (~13.1 hours after the
burst).  The potential host galaxy (Miller et al., GCN 10377
Not found
 
 
) is
clearly detected in mosaics taken simultaneously in the J, H, and Ks
filters (effective exposure time of 2293 seconds).  The preliminary
photometry yields:

exp(s)  filt    mag
==============================
2293    J       18.35 +/- 0.07
2293    H       17.55 +/- 0.08
2293    Ks      16.56 +/- 0.08
==============================

A preliminary estimate of the metallicity from the Halpha and [N II]
line ratios suggest a super-solar metallicity (~1.5 solar metallicity,
using Asplund 2009 for Solar oxygen abundance). At a redshift of z =
0.41 (Cenko et al., GCN 10389
Not found
 
 
), and assuming a Lambda-CDM cosmology
with H_0=74 km/s/Mpc, Omega_M=0.27 and Omega_Lambda=0.73, we calculate
the distance modulus to be 41.65 mag, which implies a rest-frame
H-band magnitude of about -25 mag. This extreme luminosity, coupled
with what appears to be strong optical reddening (Cenko et al., GCN
10389
Not found
 
 
) suggests that this galaxy is a luminous infrared galaxy
(LIRG/ULIRG). While the physical connection to GRB 100206A has not
been definitively established, the probability of a chance coincidence
of such a galaxy with a SHB is low, providing an a posterori argument
for a physical connection.

All magnitudes given in the Vega system, calibrated to 2MASS.  No
correction for Galactic extinction has been made to the above reported
values.