TITLE:   GCN CIRCULAR
NUMBER:  30039
SUBJECT: GRB 210515C: Swift/UVOT Upper Limits
DATE:    21/05/17 17:35:31 GMT
FROM:    Sam LaPorte at PSU  <sjl5346@psu.edu>

 GRB 210515C: Swift/UVOT Upper Limits

S. J. LaPorte (PSU) and A. D'Ai (INAF-IASFPA)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 210515C
40 s after the BAT trigger (A. D'Ai et al., GCN Circ. 30020).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 30023)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

b                      486            851            58      >18.60
uvm2                758           5041         216       >18.99
u                      231           5285         311       >19.33
v                      561           4836         235       >18.60
uvw1                610           5246         235        >18.89
uvw2              4432           4631         196        >18.90
white                 72             942         271        >20.12


The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.011 in the direction of the burst
(Schlegel et al. 1998).