[vsnet-grb-info 4286] GRB 070208: Early IR detection and afterglow astrometry

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6079
SUBJECT: GRB 070208: Early IR detection and afterglow astrometry
DATE:    07/02/08 11:00:33 GMT
FROM:    Josh Bloom at UC Berkeley  <jbloom at astron.berkeley.edu>

J. S. Bloom (UC Berkeley) reports on behalf of large group:

We began observing GRB 070208 (Sato et al. GCN 6074) with the robotic  
IR telescope PAIRITEL at 2007-02-08 09:12:26 UTC, 1 minute 52 seconds  
after the trigger. Consistent with the position of the fading source  
reported by Guidorzi et al. (GCN 6077; see also Fox et al. 6078) we  
find a new IR point source, offset from the nearby SDSS galaxy.  
Astrometry of the afterglow position relative to 2MASS gives a  
location of (J2000):

   RA: 13:11:32.607
   DEC: +61:57:54.37

(rms uncertainty of 350 mas in both coordinates). Adopting the  
nominal SDSS position for the center of the putative host (Mirabal et  
al. 6075), the afterglow is offset by 2.48" W, 2.77" S.

In a stacked exposure from 2007-02-08 09:12:26 to 09:28:44 we find a  
preliminary magnitude of J=17.52 +/- 0.16, Ks=16.19+/-0.18.

A finder showing the XRT position (Sato et al. 6074; yellow circle),  
SDSS sources (white squares), and the FTN optical afterglow position  
may be found at:
   http://lyra.berkeley.edu/~jbloom/grb070208.ps.gz

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