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GCN Circular 6481

Subject

Swift/UVOT refined analysis of GRB070531

Date

2007-05-31T20:28:55Z (17 years ago)

From

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

M. De Pasquale (MSSL/UCL) and C. B. Markwardt (GSFC/UMD)
report, on the behalf of Swift UVOT team:

   The Swift Ultraviolet/Optical telescope (UVOT) began
its White filter finding chart exposure of GRB070531
(Markwardt et al., GCN circ. 6475Not found
 
 
) 135 seconds after
the trigger. No optical afterglow is detected inside
the refined XRT error circle (Page et al., GCN circ.
6477Not found
 
 
), in the initial V and White filter exposures and
the summed exposures in all filters.

   In the following table, we report the 3 sigma
upper limits for any optical afterglow .


   Filter      Time (s)    Exp(s)     3sigma UL Mag

   White       132-231      98           19.5

   White       132-966     207           19.9


    V          238-637     393           19.2

    V          238-1111    524           19.3


    B          716-726      10           18.2

    U          692-4845     76           18.9

   UW1         668-4803    236           19.2

   UM2         643-4598    236           19.5

   UW2         745-764      20           17.8


   No correction has been made for the Galactic
reddening toward the burst, E(B-V)=0.38