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GCN Circular 36517

GRB 240516A: Swift/UVOT Upper Limits
2024-05-20T13:03:20Z (2 months ago)
Sam Shilling at Lancaster University <>
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S. P. R. Shilling (Lancaster U.), S. R. Oates (Lancaster U.), N. P. Kuin (UCL-MSSL),
A. A. Breeveld (UCL-MSSL) and T. M. Parsotan (GSFC) report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240516A
150 s after the BAT trigger (Parsotan et al., GCN Circ. 36493).
No optical afterglow consistent with the XRT position
(Parsotan et al., GCN Circ. 36493) 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 initial exposures are:

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

white_FC          151          153            2          >17.8
white             150          1689           90         >19.9
v                 5228         5427           197        >18.9
m2                5432         5632           197        >18.9
w1                5638         5838           197        >19.1
u                 5843         5948           104        >19.1

We note that the first orbit of data only contained observations in the
white filter. The other filters are from a later orbit of data.

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 2.390 in the direction of the burst
(Schlegel et al. 1998).
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