TITLE:   GCN CIRCULAR
NUMBER:  9834
SUBJECT: GRB 090817: Swift/UVOT Observations of a Possible Late-Time Brightening
DATE:    09/08/24 18:58:29 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <Stephen.T.Holland@nasa.gov>

S. T. Holland (CRESST/GSFC/USRA), A. Breeveld (MSSL/UCL), and
W. Baumgartner (GSFC/UMBC) report on behalf of the Swift UVOT team:

      Swift/UVOT observed the USNO-B1.0 source 1341-0096763 (Evans et
al. 2009, GCN Circ. 9819; Rumyantsev et al. 2009, GCN Circ. 9828;
Holland et al. 2009, GCN Circ. 9831), which is located inside the XRT
error circle (Evans et al., 2009, GCN Circ. 9819), at approximately 6
and 7 days after the INTEGRAL trigger (Beckman et al., 2009, GCN
Circ. 9815).  A preliminary examination of the UVOT data yields weak
evidence that the source may have brightened by approximately 0.5 mag
in the UVOT v band between approximately 6.5 and 7.1 days.  Our
observations are consistent with a supernova rising to maximum light.
However, we stress that further observations are needed to confirm
this.  Follow-up photometric and spectroscopic observations of this
source are strongly encouraged.