TITLE:   GCN CIRCULAR
NUMBER:  6215
SUBJECT: GRB070318: Swift UVOT continuing observations
DATE:    07/03/18 23:35:03 GMT
FROM:    Mat Page at MSSL/Swift  <mjp@mssl.ucl.ac.uk>

M. Page (MSSL-UCL), M. Chester (PSU), J. R. Cummings (NASA/UMBC) report
on behalf of the Swift/UVOT team:

The Swift/UVOT began taking data in the field of GRB070318 88s after
the BAT trigger (Cummings et al., GCN 6210, Marshall et al., GCN 6213).
The afterglow is detected in all UVOT filters. The photometry results 
are given for the 7 UVOT filters below. The first White exposure was 
affected by the star tracker loss of lock, so results from this exposure 
are not reported below.


Filter  T+(s)   Exp(s)  Mag
White   706     10      15.53 +/- 0.08

White  6364    197      18.14 +/- 0.07

V       214    400      15.43 +/- 0.02

B       692     10      16.25 +/- 0.12
B      6159    197      18.91 +/- 0.13

U       667     19      15.89 +/- 0.09
U      5955    197      18.23 +/- 0.11

UVW1     644     19     16.89 +/- 0.18
UVW1    5750    197     19.62 +/- 0.30

UVM2     619     19     17.97 +/- 0.37
UVM2    5545    197     > 19.87 (3-sigma UL)

UVW2     870     19     18.03 +/- 0.30
UVW2    6569    197     > 20.37 (3-sigma UL)

T+ is the start time of the exposure since the BAT trigger. These
magnitudes are not corrected for the expected extinction of
E(B-V)=0.017.