Oates, S R and Marshall, F E and Breeveld, A A and Kuin, N P M and Brown, P J and De Pasquale, M and Evans, P A and Fenney, A J and Gronwall, C and Kennea, J A and Klingler, N J and Page, M J and Siegel, M H and Tohuvavohu, A and Ambrosi, E and Barthelmy, S D and Beardmore, A P and Bernardini, M G and Campana, S and Caputo, R and Cenko, S B and Cusumano, G and D’Aì, A and D’Avanzo, P and D’Elia, V and Giommi, P and Hartmann, D H and Krimm, H A and Laha, S and Malesani, D B and Melandri, A and Nousek, J A and O’Brien, P T and Osborne, J P and Pagani, C and Page, K L and Palmer, D M and Perri, M and Racusin, J L and Sakamoto, T and Sbarufatti, B and Schlieder, J E and Tagliaferri, G and Troja, E (2021) Swift/UVOT follow-up of gravitational wave alerts in the O3 era. Monthly Notices of the Royal Astronomical Society, 507 (1). pp. 1296-1317. ISSN 0035-8711
Full text not available from this repository.Abstract
In this paper, we report on the observational performance of the Swift Ultra-violet/Optical Telescope (UVOT) in response to the gravitational wave (GW) alerts announced by the Advanced Laser Interferometer Gravitational Wave Observatory and the Advanced Virgo detector during the O3 period. We provide the observational strategy for follow-up of GW alerts and provide an overview of the processing and analysis of candidate optical/UV sources. For the O3 period, we also provide a statistical overview and report on serendipitous sources discovered by Swift/UVOT. Swift followed 18 GW candidate alerts, with UVOT observing a total of 424 deg2. We found 27 sources that changed in magnitude at the 3σ level compared with archival u- or g-band catalogued values. Swift/UVOT also followed up a further 13 sources reported by other facilities during the O3 period. Using catalogue information, we divided these 40 sources into five initial classifications: 11 candidate active galactic nuclei (AGNs)/quasars, three cataclysmic variables (CVs), nine supernovae, 11 unidentified sources that had archival photometry, and six uncatalogued sources for which no archival photometry was available. We have no strong evidence to identify any of these transients as counterparts to the GW events. The 17 unclassified sources are likely a mix of AGN and a class of fast-evolving transient, and one source may be a CV.