[vsnet-grb-info 15993] GRB 150103A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17275
SUBJECT: GRB 150103A: Swift/UVOT Upper Limits
DATE:    15/01/04 04:04:17 GMT
FROM:    Lea Hagen at PSU  <lea.zernow.hagen at gmail.com>

L. M. Z. Hagen (PSU) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150103A
135 s after the BAT trigger (Hagen et al., GCN Circ. 17269). No optical
afterglow consistent with the XRT position (Osborne et al. GCN Circ.
17272) 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)         135          284          147         >20.49
white              573         7047          618         >21.08
v                  624         6018          293         >19.31
b                  549         6841          471         >20.41
u (fc)             293          543          245         >19.66
u                  698         6635          451         >19.95
uvw1               673         6429          471         >19.73
uvm2               648         6224          471         >19.54
uvw2               599         7179          417         >19.67

The magnitudes in the table are not corrected for the Galactic extinction
due to the large, but uncertain, reddening of E(B-V) = 1.46 in the
direction of the burst (Schlegel et al. 1998).