GCN Circular 6545
Subject
GRB 070616: TLS observation
Event
Date
2007-06-17T01:39:22Z (18 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, U. Laux, B. Stecklum and S. Klose (TLS Tautenburg) report:
We observed the field of Swift GRB 070616 (Starling et al., GCN 6542) with
the Tautenburg 1.34m Schmidt telescope. A single 600 second image in Ic
was obtained before clouds forced us to shut down. The airmass was 1.95.
At the XRT position (Starling et al., GCN 6542), we do not detect any
afterglow. Assuming the USNO B1.0 star at RA = 02:08:34.67,
Dec. = +56:56:22.3 to have I = 15.44, we derive the following upper limit
for the image:
date time (days) exp. time Ic limit
070617.00838 0.32119 600 20.3
We caution that, as Starling et al. (GCN 6542) noted, this is very close
to a star in the USNO B1.0 catalog. Thus, the true limiting magnitude at
the XRT position is much shallower than what is stated above.
Judging from the early BAT/XRT light curve, this is a real GRB that
happens to lie close to a bright star by chance. As the field is crowded,
the probability of such a chance alignement is non-negligible.
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