[vsnet-grb-info 16830] GRB 150801B: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18111
SUBJECT: GRB 150801B: Swift/UVOT Upper Limits
DATE:    15/08/02 22:58:24 GMT
FROM:    Lea Hagen at PSU  <lea.zernow.hagen at gmail.com>

L. M. Z. Hagen (PSU) and B. Sbarufatti (INAF-OAB/PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150801B
84 s after the BAT trigger (Sbarufatti et al., GCN Circ. 18104).
No optical afterglow consistent with the XRT position (Evans et al.,
GCN Circ. 18108) 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) exposure and subsequent exposures are:

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

white_FC            83          233          147         >20.17
white              575        12513         1345         >21.35
v                  625        16812          901         >19.63
b                  551        11601         1264         >20.68
u_FC               295          545          245         >19.42
u                  699         7399          490         >19.53
uvw1              1105         7194          432         >19.41
uvw2              4943        13218          884         >19.89

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.24 in the direction of the burst
(Schlegel et al. 1998).