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GCN Circular 3371

Subject
GRB 050505: Further Swift UVOT observations.
Date
2005-05-06T14:17:46Z (19 years ago)
From
Simon Rosen at MSSL-UCL <srr@mssl.ucl.ac.uk>
S. Rosen (MSSL), C. Hurkett (Leicester), S. Holland (GSFC), P. Roming 
(PSU), A. Blustin (MSSL), N. Gehrels (GSFC), K. Mason (MSSL), J. Nousek 
(PSU), on behalf of the Swift UVOT team

Further to the initial Swift UVOT results (Rosen et. al. 3367) we report
the results of co-added, deeper exposures of GRB 050505 with the Swift
Ultra-Violet/Optical Telescope (UVOT) on May 06, 2005.

We detect no source at the Keck determined location  (Cenko et al, GCN 
3366) in any of the UVOT filters with the following 5 sigma and 3 sigma
limits (in 6" radius apertures)


Filter    Lim_Mag      Lim_mag   Total duration (s)   T_range (s)
           5sigma       3sigma

V          19.82        20.35        2527            2807  -  28543
B          20.50        21.04        1999            3236  -  26917
U          20.26        20.84        2890            3132  -  22757
UVW1       20.81        21.36        1999            3029  -  22040
UVM2       21.13        21.68        2422            2924  -  21132
UVW2       21.27        21.83        1997            3342  -  27826

T_range is since the BAT trigger time (Hullinger et al. 3364).

The magnitudes are based on preliminary zero-points, measured in
orbit, and will require refinement with further calibration.

We note that for the estimated redshift of 4.1 - 4.3 (GCN 3368), the Lyman 
limit lies between the UVOT B and V filters - the lack of a UVOT 
detection in V may be significant, depending on the brightness of the 
source detected by Keck and the true redshift.

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