[vsnet-grb-info 5845] GRB 080319B: UVOT Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7496
SUBJECT: GRB 080319B: UVOT Observations
DATE:    08/03/21 11:34:39 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <sholland at milkyway.gsfc.nasa.gov>

S. T. Holland (CRESST/USRA/GSFC) & J. L. Racusin (PSU) report on
behalf of the Swift/UVOT team:

      The Swift/UVOT observed the field of GRB 080319B starting 51 s
after the BAT trigger (Racusin et al., GCN Circ. 7427).  We detect the
optical afterglow all filters.  Preliminary magnitudes are reported
below.

Filter    T_start (s) T_stop  Exposure      Mag  Err  Comment
    v          175        575      393    <11.5        Saturated
    b          654        664       10     13.39 0.01
    u          630        649       19     12.44 0.01
   uvw1        605        625       19     12.49 0.02
   uvm2        581        600       19     13.39 0.05
   uvw2        685        705       19     13.36 0.04
  white         67        169       98    <13.9        Saturated

The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0 .01 mag (Schlegel et al.,
1998, ApJS, 500, 525).  The photometry is on the UVOT flight system
described in Poole et al. (2008, MNRAS, 383,627).