GCN Circular 10436
Subject
GRB 100219A: Swift/UVOT Detection of the Optical Afterglow
Event
Date
2010-02-20T00:18:39Z (16 years ago)
From
Stephen Holland at USRA/NASA/GSFC/SSC <Stephen.T.Holland@nasa.gov>
S. T. Holland (CRESST/GSFC/USRA) and
A. Rowlinson (U. Leicester) report
on the behalf of the Swift UVOT team:
Swift/UVOT began settled observations of the field of GRB
100219A starting 161 s after the BAT trigger (Rowlinson, et al. 2010,
GCN Circ. 10430). Settled exposures started at T+183 s. The source
reported by Holland, et al. (2010, GCN Circ. 104322) is seen in the
white and u-band exposures. Preliminary 3-sigma magnitudes and upper
limits are
Filter T_start T_stop Exp(s) Mag Err
------------------------------------------------------
white 183 333 150 20.91 0.28
white 875 1718 225 >21.6 3-sigma UL
v 673 1767 136 >19.7 3-sigma UL
b 598 1693 117 >20.5 3-sigma UL
u 341 1668 343 20.35 0.35
uvw1 722 1812 113 >19.9 3-sigma UL
uvm2 697 1792 39 >18.3 3-sigma UL
uvw2 648 1297 78 >19.5 3-sigma UL
------------------------------------------------------
The fading observed between T+183 s and T+875 s suggests that
this is the afterglow of GRB 100219A superimposed on the host galaxy
candidate of Bloom and Nugent (2010, GCN Circ. 10433). The weak
detection in the u band suggests that this source has a redshift of
less than approximately 2.8.
The quoted magnitudes have not been corrected for the expected
Galactic extinction along the line of sight corresponding to a
reddening of E_{B-V} = 0.08 mag (Schlegel, et al., 1998, ApJS, 500,
525). All photometry is on the UVOT photometric system described in
Poole et al. (2008, MNRAS, 383, 627).