GCN Circular 6660

Subject

Swift/UVOT refined analysis of GRB070724

Event

Date

2007-07-24T18:05:38Z (19 years ago)

From

Massimiliano de Pasquale at MSSL-UCL <mdp@mssl.ucl.ac.uk>

M. De Pasquale (MSSL-UCL) and H. Ziaeepour (MSSL-UCL) report on
the behalf of the Swift UVOT/team:

  The Swift/UVOT observed the field of GRB070724 starting 58s after
the BAT trigger (Ziaaepour et al. GCN circ. 6654Loading...
 
 ). Inside the
refined XRT error circle (Page et al., GCN circ 6659Loading...
 
 ) we do not
find any new source, either in the first finding chart exposures
in the White and V filter or in the summed exposures of any of the
UVOT filters.

  The 3 sigma upper limits for detecting a source inside the XRT
error circle are:

  Filter  T obs (s)  Exp (s)  Mag (3 sigma u.l.)

  White    76-176      98           20.4

   v      182-581     393           19.5


  White   76-5531     380           21.1

   v     182-5941     806           20.0

   b     662-5325     216           20.3

   u     636-6456     332           20.0

  uvw1   612-6352     432           20.4

  uvm2   587-6146     432           20.4

  uvw2   692-5736     432           20.7


  No correction has been done for the expected low Galactic
reddening towards the burst, E(B-V)=0.01 (Schlegel et al.
11998).