[vsnet-grb-info 426] GRB021004: Upper limits from recent and historical observations

[GCN Circulars <gcncirc@lheawww.gsfc.nasa.gov>]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  1572
SUBJECT: GRB021004: Upper limits from recent and historical observations 
DATE:    02/10/05 00:12:36 GMT
FROM:    Brian Lee at LBL  <bclee@lbl.gov>

W. M. Wood-Vasey, G. Aldering, and B. C. Lee, Lawrence Berkeley
National Laboratory, using images obtained by E. F. Helin, S. Pravdo,
M. Hicks, and K. Lawrence (Near-Earth Asteroid Tracking project, Jet
Propulsion Laboratory), report upper limits for pre-discovery
observations at the location of the object identified by Fox et
al. (GCN 1564) as the optical counterpart to GRB 20021004 from
unfiltered observations with the Oschin 48" telescope at Palomar
Observatory (the same instrument as used by Fox et al.).

A co-addition of historical images from 13 October 2001, 26 October
2001, 5 November 2001, 3 September 2002, 3 October 2002 (all dates UT)
from the same instrument show no source visible at this location to a
limiting unfiltered magnitude of 22.3 (calibrated to USNO R-band stars
on the image frame) at a S/N of 3.

A coaddition of images from 3 October 2002 UT shows no source visible
at this location to a limiting unfiltered magnitude of 21.4
(calibrated to USNO R-band stars on the image frame) at a S/N of 3.

The specific UT times for the 3 October 2002 UT observations are:

07:24:18
07:54:50
08:25:19

The historical co-additions of the all 
images mentioned above is available at:

http://supernova.lbl.gov/~wwoodvas/GRB/

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