[vsnet-grb-info 3947] GRB 061028: z band imaging

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  5768
SUBJECT: GRB 061028: z band imaging
DATE:    06/10/28 18:51:37 GMT
FROM:    Josh Bloom at UC Berkeley  <jbloom at astron.berkeley.edu>

GRB 061028: z-band imaging

J. S. Bloom (UC Berkeley), D. Charbonneau, M. J. Holman, E. E. Falco  
(Harvard/CfA), H-. W. Chen (U Chicago) report on behalf of a larger  
collaboration:

"We observed the field of GRB 061028 (Sakamoto et al. GCN 5762) using  
the z-band filter of Keplercam mounted on the Mt. Hopkins 48-inch  
telescope. In a stacked series of 5 minute exposures from 06:20 -  
07:21 Oct 28, 2006 UTC (from about 4 - 5 hours after the GRB  
trigger), we find no detected source consistent with the revised XRT  
position (Cusumano et al. GCN 5767). We do note the presence of a  
marginally detected faint red source (S1) to the north of the error  
circle that is not in the DSS2 F or N plates at position 06:28:54.6,  
46:18:01 (J2000). Photometric calibration is in progress but, for  
reference, S1 is about 2.1 mag fainter in z-band than the object at  
06:28:54.1, +46:18:15. Our 3 sigma limiting magnitude is roughly 0.2  
mag fainter than S1."

  An image of the field (XRT 90% confidence region circled) is  
located at:
    http://lyra.berkeley.edu/~jbloom/grb061028_zcompare_bloom.ps.gz

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