[vsnet-grb-info 6125] GRB080520: Swift/UVOT observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7758
SUBJECT: GRB080520: Swift/UVOT observations
DATE:    08/05/21 13:12:58 GMT
FROM:    Samantha Oates at MSSL  <sro at mssl.ucl.ac.uk>

S.R. Oates (MSSL/UCL) and D. Grupe (PSU) report on behalf of
the Swift/UVOT team

The Swift/UVOT began settled observations of the field of GRB 080520, 105s 
after the BAT trigger (Grupe et al., GCN 7753). We detect the afterglow in 
the white, v filters at the position:

RA(J2000.0)  =  18:40:46.30
DEC(J2000.0) = -54:59:31.0

with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence).
This position is consistent with the UVOT enhanced XRT position (Goad et 
al., GCN 7755).

UVOT magnitudes and 3 sigma upper limits are reported below for the single
and coadded images:

Filter    Tstart(s)  Tstop   Expo(s)   Magnitude/3sigUL
-----------------------------------------------------
white       105      204    98       19.59 +/- 0.12
white       858      958    98       20.58 +/- 0.28
v           211      610    400      20.26 +/- 0.38
v           964      1299   330      19.96 +/- 0.45
b           691      6273   216      > 20.92
u           666      6068   197	     > 20.60
w1          641      5862   236      > 20.33
m2          617      7079   418      > 20.38
w2          720      6684   216      > 20.25
-----------------------------------------------------

These magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E{B-V} = 0.08 mag (Schlegel et al.
1998). The photometry is on the UVOT flight system described in Poole
et al. (2008, MNRAS, 383, 627).