GCN Circular 6884
Subject
GRB 071010B: Bright OT confirmed with TLS
Event
Date
2007-10-11T14:56:36Z (18 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, C. Hoegner & R. Filgas (TLS Tautenburg) report:
We observed the field of GRB 071010B (Markwardt et al., GCN 6871) with the
TLS 1.34m Schmidt telescope under bad weather conditions (low
transparency, passing clouds). We obtained 9 600 second integrations in
the Rc Filter starting at UT 1:26:44 (0.2 days after the GRB). The
afterglow (Oksanen, GCN 6873) is clearly detected on several frames, the
others were lost to passing clouds.
We measure a refined OT position (J2000) in comparison to the USNO-B1.0
catalog:
RA = 10:02:09.24
Dec. = +45:43:49.7
with errors of 0".7.
This is in accordance with the position of Oksanen (GCN 6873) and the
Swift XRT detection (Kennea et al., GCN 6878).
Preliminary photometry on raw images yields a decaying afterglow. Assuming
the USNO-B1.0 star at RA = 10:02:06.71, Dec. = +45:42:34.2 (J2000) to have
R2 = 17.26, we find the following magnitudes:
Date Mid-Time Rc Rc error
11.06361 0.19848 18.61 0.07
11.07113 0.20600 18.73 0.05
11.07865 0.21352 18.87 0.06
11.13149 0.26637 19.21 0.05
Oksanen (GCN 6873) reported the OT to have R > 18 mag already in the first
hour, therefore our bright detections may indicate a slow decay or a
rebrightening. This GRB was a bright, soft FRED (Markwardt et al., GCN
6877; Golenetskii et al., GCN 6879) with a well determined peak energy.
This may indicate an event at relatively low redshift. Further photometric
and especially spectroscopic follow-up is encouraged.
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