GCN Circular 4600

N. Butler and J. S. Bloom (UC Berkeley):

We determine a refined XRT positions for GRB060123 (Palmer et al.,  
GCN 4584
Not found
 
 
)
by matching the positions of X-ray sources to positions of SDSS  
sources.  A
similar procedure was employed in GCN 4500
Not found
 
 
 to refine the XRT position  
for
GRB060108.  Using 4 X-ray sources detected in 4.5 ksec of PC mode data
and 6 SDSS sources, we determine a frame offset for the XRT of:

Frame Offset: RA  -2.28 ; Dec 2.0 , 90% Conf. Error:  2.7"

Our refined XRT position for GRB060123 is then:

RA  11h 58m 47.66s       ;      DEC +45d 30' 50.55"
                                                         +/-  
3.1" (90% Conf.)

This refined XRT position is coincident with the SDSS galaxy noted in  
Bloom et al. (GCN 4595
Not found
 
 
).  Given this, we suggest that this  
coincidence appears to disfavor the high-redshift hypothesis for the  
burst (Palmer et al., GCN 4584
Not found
 
 
)."

The X-ray/optical source offsets are shown at:
     http://astro.berkeley.edu/~nat/060123/crosscor_sdss.jpg

The XRT overlap atop the SDSS and PAIRITEL images is:
     http://astro.berkeley.edu/~jbloom/grb060123-nat.ps.gz

We thank Dave Burrows at PSU for his assistance.