TITLE:   GCN CIRCULAR
NUMBER:  7901
SUBJECT: GRB080623: Swift UVOT followup observations
DATE:    08/06/23 20:43:04 GMT
FROM:    Alice Breeveld at MSSL-UCL  <aad@mssl.ucl.ac.uk>

A. A. Breeveld (MSSL/UCL) and T. N. Ukwatta (GSFC/GWU) report on behalf
of the Swift/UVOT team.

The Swift Ultra-Violet/Optical Telescope (UVOT) began settled
observations of GRB 080623 (Ukwatta et al., GCN Circ. 7894) 22.15 
minutes after the trigger, as reported in Holland, GCN Circ. 7896.  We 
confirm that no afterglow is detected at the position of the enhanced 
XRT position (Beardmore et al., GCN Circ. 7898) in the initial finding 
chart or subsequent summed images.

The following table gives the 3 sigma upper limits in all filters.

Filter  T_start(s)  T_stop(s)  Exp(s)  Mag UL (3sig)

white   1329        1428       98.1    >20.4
white   1559        2713       76.9    >20.3
white   8133        8332      196.6    >20.8
v       1436        2598      155.6    >19.0
b       1535        2698      155.5    >19.9
u       1510        2673      155.4    >19.7
uvw1    1486        2648      155.5    >19.4
uvm2    1460        2623      155.6    >19.1
uvw2    1575        2573      136.1    >19.3

The values quoted above are in the UVOT photometric system (Poole et al.
2008, MNRAS, 383, 627).  No correction has been made for the large 
expected extinction corresponding to E(B-V) of 0.35 mag in
the direction of the burst (Schlegel et al. 1998).