[vsnet-grb-info 17686] GRB 160228A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19123
SUBJECT: GRB 160228A: Swift/UVOT Upper Limits
DATE:    16/02/29 22:50:24 GMT
FROM:    Frank Marshall at GSFC  <femarsha at khamseen.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and D. Malesani (DARK/NBI)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160228A
83 s after the BAT trigger (Malesani et al., GCN Circ. 19107).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 19110) or the
position of the GROND optical afterglow candidate
(Delvaux et al. GCN Circ. 19114)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposures and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC            83          233          147         >20.2
u_FC               296          546          246         >19.5
white               83        10111          342         >20.5
v                  625         5975          236         >19.0
b                  551         6695          138         >19.8
u                  296         6589          462         >20.2
w1                 675         6385          235         >19.8
m2                 650         6179          236         >19.9
w2                 601         5770          235         >19.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.06 in the direction of the burst
(Schlegel et al. 1998).