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GCN Circular 3444

Subject

Swift UVOT Observations of GRB 050520

Date

2005-05-20T21:04:44Z (19 years ago)

From

Caryl Gronwall at PSU/Swift-UVOT <caryl@astro.psu.edu>

C. Gronwall (PSU), J. Norris (GSFC), A. Morgan (PSU),
P. Schady (MSSL), N. Gehrels (GSFC), on behalf of the
Swift UVOT Team

INTEGRAL detected GRB 050520 at 00:05:53 UT on 20th May 2005
(Gotz et al., GCN 3430Not found
 
 
).  Swift executed a Target of Opportunity
observation of the INTEGRAL position.  The Swift Ultra-Violet/Optical
Telescope (UVOT) began observations of GRB050520 at UT 02:13:38,
approximately 2hr 8 minutes after the INTEGRAL detection.

We detect no new source within the Swift XRT error circle
(Kennea et al., GCN Circ. 3443Not found
 
 
) 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 (hr)
           5sigma       3sigma

V          19.84        20.39        3069            5.48 - 13.26
B          21.05        21.60        2699            4.98 - 11.90
U          20.58        21.13        2674            3.62 - 11.65
UVW1       21.30        21.86        3173            3.37 - 13.73
UVM2       21.36        21.91        2824            2.13 - 13.50
UVW2       21.64        22.19        2456            5.23 - 12.12

T_range is time since the INTEGRAL detection.

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

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