GCN Circular 6014

H. A. Krimm (GSFC/USRA) , P. Boyd (GSFC), V. Mangano (INAF-IASFPA),
F. Marshall (GSFC), B. Sbarufatti (INAF-IASFPA), N. Gehrels (GSFC)
report on behalf of the Swift Team

Based on its unusual afterglow light curve, the Swift team declares
GRB 070110 to be a "burst of interest".  Although the burst is
59 degrees from the Sun and moving closer to the Sun, we will
continue observations of the afterglow in the U filter over the next
several days.  We  encourage multiwavelength observations of this
unusual burst throughout its lightcurve.

Swift observations of GRB 070110 are discussed in GCN Report 26.2
(http://gcn.gsfc.nasa.gov/report_archive.html)

As reported previously, after a very steep drop, the XRT light curve
started to rise at T+35 ksec, reaching 3.2 X 10^-2 counts/sec.
Then between T+45 ksec and T+75 ksec, the light curve again turned
over, dropping to 6 X 10^-3 counts/sec at 100 ksec, before flattening
again.  Although flares have been observed in other bursts at
times > 10 ksec, such behavior (a steep drop followed by a slow rise)
has not before been observed in a Swift burst (see for example
P. O'Brien et al (2006), ApJ 647, 1213).

The UVOT light curve is even more extraordinary.  The afterglow
was originally detected at V=20 at T+104 sec and continues to be
detectable in all visible filters (V, B and U) with a common power
law decay index of -0.47 +- 0.02 in all three filters.  At T+203 ksec,
the afterglow is seen at V=21.6. Thus the optical light curves do not show
any of the extreme variability seen in the X-rays.  It is very rare that
a burst which was first detected at V=20 is still detectable at
T >200 ksec. The afterglow was not detected in the UVW1 filter, with
a 3-sigma upper limit of 22.26 for a 4071-sec exposure beginning at T+75 ks.
This non-detection is consistent with the redshift z=2.352 reported 
for the burst (Jaunsen et al, GCN 6010
Not found
 
 
).

[GCN OPS NOTE(12jan07): Per request of one of the authors of GCN 6010
Not found
 
 

and with the concurance of the GCN admistrator, the author for the 
6010 reference was changed from Malesani to Jaunsen.]