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GCN Circular 16123

GRB140419A: UVOT detects fading afterglow in white but not in u filter
2014-04-19T07:56:22Z (10 years ago)
Paul Kuin at MSSL <>
NPM Kuin (MSSL-UCL), and F. E. Marshall (NASA/GSFC) report on behalf of
the Swift Team:

UVOT started observing GRB 140419A starting 96 seconds after the BAT
The initial finding chart exposures with the White and U filter show a
fading source in the white filter which we identify with the afterglow:

The estimated magnitudes are as follows:

filter starttime endtime magnitude error
wh      96         246    16.01    0.06
u      308         558    >19.6
wh     862        1012    17.96    0.09.

The source is not seen in the u filter, which suggests a redshift larger

No correction has been made for the expected extinction corresponding to
E(B-V) of 0.03.
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