[vsnet-grb-info 5807] GRB 080319D: Swift/UVOT Refined Analysis of the Fading Optical Afterglow Candidate

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7458
SUBJECT: GRB 080319D: Swift/UVOT Refined Analysis of the Fading Optical Afterglow Candidate
DATE:    08/03/19 19:54:49 GMT
FROM:    Stefan Immler at NASA/GSFC  <stefan.m.immler at nasa.gov>

S. Immler (CRESST/GSFC/UMD) and P. J. Brown (PSU) report on behalf
of the Swift UVOT team:

The Swift/UVOT observations of the field of GRB 080319D (trigger 306793)
starting 151 seconds after the BAT trigger (Brown, et al., GCN Circ. 7453)
reveal a fading optical afterglow candidate. The white and v-filter 
magnitudes
are as follows:

Filter        T_start (s)    T_stop (s)        Exp (s)    Mag (3-sigma UL)
----------------------------------------------------------------------------------------------
White    151        251            100        19.7+/-0.3
White    866        966            100        20.2+/-0.4
v        257        657            400        >19.5
v        972        1362        400        >19.5
----------------------------------------------------------------------------------------------

No correction has been made for the expected Galactic extinction 
corresponding
to E(B-V) of 0.19 (Schlegel, et al. 1998). The position of the optical 
afterglow
candidate is

RA (2000) = 06h 37m 53.6s
Dec (2000) = +23d 56' 34.2"

with an uncertainty of 0.5 arcsec, which is 2.2 arcsec offset from the XRT
position (Brown, et al., GCN Circ. 7453).