TITLE:   GCN CIRCULAR
NUMBER:  6213
SUBJECT: GRB 070318: Swift/UVOT Continued Observations
DATE:    07/03/18 17:09:46 GMT
FROM:    Frank Marshall at GSFC  <marshall@milkyway.gsfc.nasa.gov>

F.E. Marshall (NASA/GSFC) and J.R. Cummings (NASA/UMBC) report
on behalf of the Swift team:

The bright optical afterglow of GRB 070318 (Cummings et al., GCN Circ. 6210)
is following an approximately power-law decay. At 13,000 sec. after the
trigger, the magnitude in the UVOT B filter is ~19.9 with a best-fit
decay index of 1.16. If this rate of decay continues, the B magnitude
will be 22.3 at one day after the trigger and 23.2 a day later.
 
The afterglow has been detected in all 7 UVOT filters indicating that
the redshift is less than ~2.

Observations with ground-based telescopes are encouraged.