[AAVSO-HEN] GRB090118 Swift/UVOT upper limits

[grb at aavso.org]

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TITLE:   GCN CIRCULAR
NUMBER:  8827
SUBJECT: GRB090118 Swift/UVOT upper limits
DATE:    09/01/19 11:47:20 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps at mssl.ucl.ac.uk>

P. Schady (MSSL-UCL) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began white-band observations of the field of the  
likely GRB candidate detected in the BAT Slew Survey (BATSS), GRB  
090118 (Copete et al., GCN 8825) at 2009-01-018 20:55:35 UT, 25.3 ks  
after the burst. We do not detect any new source within the Swift BAT  
error circle (Copete et al., GCN 8825) in a co-added white-band image  
down to the following 5-sigma upper limit:

Filter    T_start  T_stop  Exp         Mag
                (ks)       (ks)       (s)    (5-sigma upper limit)
-------------------------------------------------------------
white       25.3    35.3    1292     > 21.1
-------------------------------------------------------------

The quoted upper limits have not been corrected for the expected  
Galactic extinction along the line of sight of E_(B-V) = 0.13 mag. All  
photometry is on the UVOT photometric system described in Poole et al.  
(2008, MNRAS, 383, 627).