TITLE: GCN CIRCULAR NUMBER: 6014 SUBJECT: GRB 070110 declared a "Burst of Interest" by Swift team DATE: 07/01/12 21:44:43 GMT FROM: Hans Krimm at NASA-GSFC 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). [GCN OPS NOTE(12jan07): Per request of one of the authors of GCN 6010 and with the concurance of the GCN admistrator, the author for the 6010 reference was changed from Malesani to Jaunsen.]