[vsnet-grb-info 22924] GRB 190706B: Swift/UVOT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25023
SUBJECT: GRB 190706B: Swift/UVOT Detection
DATE:    19/07/07 19:29:34 GMT
FROM:    Paul Kuin at MSSL  <npkuin at gmail.com>

N. P. M. Kuin (UCL-MSSL) and A. Tohuvavohu (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190706B
100 s after the BAT trigger (Tohuvavohu et al., GCN Circ. 24993).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 24995) 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           100          250          147         20.35 +/- 0.27
u_FC               312          562          246        >19.86
white              100         5778          519         >20.9
v                  642        17542          561         >19.9
b                  568         5644          292         >20.6
u                  312        13071          647         >19.9
w1                 691        11551         1204         >20.0
m2                 666         7285          490         >19.6
w2                 618        17284         1199         >20.5


The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.15 in the direction of the burst
(Schlegel et al. 1998).