[vsnet-grb-info 16776] GRB 150724A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18057
SUBJECT: GRB 150724A: Swift/UVOT Upper Limits
DATE:    15/07/24 14:41:21 GMT
FROM:    Massimiliano de Pasquale at IASF-Palermo  <m.depasquale at ucl.ac.uk>

M. De Pasquale (UCL-MSSL) and J. L. Racusin (NASA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150724A
108 s after the BAT trigger (Racusin et al., GCN Circ. 18050).
No optical afterglow consistent with the XRT position (Goad et al.
GCN Circ. 18054) 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 summed exposures are:

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

u_FC               108          358          246         >19.7

v                  415         6930          510         >19.2
b                  364        12898         1165         >20.6
u                  108        12238         1769         >20.7
w1                 464        11324         1387         >20.5
m2                 439         7135          502         >19.9
w2                 390         6726          529         >20.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.27 in the direction of the burst
(Schlegel et al. 1998).

-- 

Dr. Massimiliano De Pasquale
Research associate - Swift UVOT scientist
Mullard Space Science Laboratory, University College London