[vsnet-grb-info 14795] GRB 140413A: Swift/UVOT Observations of the Optical Afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16109
SUBJECT: GRB 140413A: Swift/UVOT Observations of the Optical Afterglow
DATE:    14/04/14 12:50:51 GMT
FROM:    Stephen Holland at STScI  <sholland at stsci.edu>

S. T. Holland (STScI) and V. D'Elia (ASDC) report on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 140413A
2221 s after the BAT trigger (D'Elia et al., 2014, GCNC 16098).  The
preliminary UVOT position is

     RA (J2000)  04:21:49.23  =   65.45512 (deg)
    Dec (J2000) -51:10:58.0   =  -51.18278 (deg)

with an estimated uncertainty of 1.79 arcsec (radius, 90% confidence,
statistical + systematic).  We detect the optical afterglow at the
position reported by Varela et al. (2014, GCNC 16099).  Preliminary
UVOT photometry and 3-sigma upper limits are presented below.

----------------------------------------------------------------
Filter        TSTART     TSTOP   Exposure       Mag   Err  Sigma
----------------------------------------------------------------
v               2377      4303        375     >19.7
b               2476      3747        235     >21.0
u               2451      3542        236     >19.9
uvw1            2427      3336        236     >19.8
uvm2            2931      3131        197     >19.5
uvw2            3957      4157        197     >20.1
white           2221      2370        147     >20.3
                3752      3951        197      21.10 0.29    3.8
----------------------------------------------------------------

The quoted magnitudes and upper limits have not been corrected for the
Galactic extinction along the line of sight to this burst of E_{B-V} =
0.01 mag (Schlafly et al. 2011, ApJS, 737, 103).  The photometry is in
the UVOT photometric system (Breeveld et al. 2011, AIP
Conf. Proc. 1358, 373).