TITLE:   GCN CIRCULAR
NUMBER:  17547
SUBJECT: Further UVOT Observations of Swift J0045.2+4151
DATE:    15/03/06 00:54:19 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

M. H. Siegel, L.M.Z. Hagen (PSU) and A. Y. Lien (GSFC/UMBC)
report on behalf of the Swift UVOT team:

Swift continues to observe the field of BAT trigger 633105 (formerly
GRB 150301C, now Swift J0045.2+4151) with a sky location in M31.
The UVOT data show no change in brightness in the optical source reported
in Hagen & Lien (GCN Circ 17541). 

Preliminary detections and 3-sigma upper limits using the UVOT
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373)
for the most recent exposures are:

Filter      T_start(s)   T_stop(s)   Exp(s)      Mag

v            338602      338728        124    >18.25
b            337955      338082        124    >19.12
u            337824      337951        124     18.45+-0.27
uvw1         337564      337819        250     18.82+-0.26
uvm2         326044      343973       4048     18.64+-0.06
uvw2         338088      338597        500     18.72+-0.14

All of these magnitudes are consistent, within uncertainties, of 
our initial and archival measures.

We further report an analysis of 207 ks of archival UVOT data for
the source.  Our analysis shows no previous variability in the source
in the UVOT photometry, which has a typical uncertainty of 0.2 mag in
the three UV filters.