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GCN Circular 33851

LIGO/Virgo/KAGRA S230518h: Swift/UVOT Upper Limits for MeerLICHT candidates: AT2023ixg and AT2023iyb
2023-05-22T15:52:54Z (17 days ago)
Alice Breeveld at MSSL-UCL <>
A. A. Breeveld (UCL-MSSL), N. P. M. Kuin (UCL-MSSL), S. R. Oates (U. of Birmingham), P. Brown (TAMU), M. De Pasquale (U. Messina), C. Gronwall (PSU), N. Klingler (NASA-GSFC/UMBC/CRESST II), F. E. Marshall (NASA/GSFC), M. J. Page (UCL-MSSL), M. H. Siegel (PSU), A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), S. Campana (INAF-OAB), S.B. Cenko (NASA/GSFC), A. D’Aì (INAF-IASFPA), P. D’Avanzo (INAF-OAB), V. D’Elia (ASI-SSDC & INAF-OAR), S. Dichiara (PSU), P.A. Evans (U. Leicester), R.A.J. Eyles-Ferris (U. Leicester), D. Hartmann (Clemson University), J.A. Kennea (PSU), S. Laha (NASA/GSFC), A.Y. Lien (GSFC/UMBC), A. Melandri (INAF-OAB), J.A. Nousek (PSU), P. O’Brien (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), D. M. Palmer (LANL), S. Ronchini (PSU), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), G. Tagliaferri (INAF-OAB), A. Tohuvavohu (U. Toronto) and E. Troja (U Tor Vergata, INAF) report on behalf of the Swift team: We report Swift/UVOT observations of the candidates AT2023ixg and AT2023iyb (Johnston et al., Astronote 2023-121) found by the the MeerLICHT 0.65m wide-field telescope during the search for the EM counterpart of the LVC event S230518h (LIGO/VIRGO/KAGRA Collaboration GCN Circ. 33813). Swift/UVOT observations of these MeerLICHT candidates began 73 hours after the LVK trigger (LIGO/VIRGO/KAGRA Collaboration, GCN Circ. 33813) in the UV filters. We do not detect either of the candidates in the UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the exposures are: Target Filter T_start(s) T_stop(s) Exp(s) 3sigUL AT2023ixg w1 267962 273767 164 18.4 m2 267775 278324 1067 19.6 w2 267587 278065 570 20.4 AT2023iyb m2 265880 272062 507 19.9 w2 265181 271869 1214 20.7 This circular is an official product of the Swift team.
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