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GCN Circular 34446

Subject
GRB230815A: Swift/UVOT upper limits
Date
2023-08-16T12:42:08Z (a year ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
Via
email
A. A. Breeveld (UCL-MSSL) and N. J. Klingler (GSFC/UMBC/CRESSTII) report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 230815A 155 s after the BAT trigger (Klingler et al., GCN Circ. 34434).
No optical afterglow consistent with the XRT position (Beardmore et al., GCN Circ. 34437) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent summed exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           155          305        147           >20.1
white              513         1531        242           >20.3
v                  390         1582        136           >18.5
b                  489         1506        114           >19.3
u                  464         6300        293           >19.4
uvw1               439         1632        136           >18.6
uvm2               761         1606         97           >18.3
uvw2               365         1557        136           >18.8

The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.73 in the direction of the burst (Schlegel et al. 1998).

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