TITLE:   GCN CIRCULAR
NUMBER:  9596
SUBJECT: GRB 090628: Swift/UVOT Upper Limits
DATE:    09/06/29 22:59:56 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@astro.psu.edu>

M. H. Siegel (PSU) and V. Mangano (INAF-IASFPA) report on behalf
of the Swift/UVOT team.

The Swift/UVOT began observing the field of GRB 090628 2790s after
the BAT trigger (Mangano et al., GCN Circ. 9585).  Data summed
from the first orbit does not reveal a source at the refined
position of the X-ray afterglow (Goad et al., GCN Circ.
9590).

The 3-sigma upper limits for the finding chart (fc) and
summed exposures are reported below:

FILTER     T_start(s)  T_stop    Exposure     Mag/3UL
=============================================================
white fc     2791       2941        147       > 20.26
white        3361       3560        196       > 20.72

v            3771       3971        196       > 19.23

b            3155       3355        196       > 20.16
b            4591       4672         79       > 19.64

u            2950       3149        196       > 19.63
u            4386       4586        196       > 19.82

uvw1         4181       4381        196       > 19.65

uvm2         3976       4176        196       > 19.33

uvw2         3566       3766        196       > 19.62
=================================================================

The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0.05 (Schlegel et al.,
1998, ApJS, 500, 525). The photometry is on the UVOT photometric
system described in Poole et al. (2008, MNRAS, 383, 627).