TITLE: GCN CIRCULAR NUMBER: 20515 SUBJECT: LIGO/Virgo G270580: UL50 observations DATE: 17/01/24 14:36:21 GMT FROM: Klaas Wiersema at U of Leceister K. Wiersema (Leicester) reports on behalf of a larger collaboration: We have performed V band tiled observations of LIGO/Virgo G270580 (LVC, GCN 20486) using the 0.5m telescope (UL50) of the University of Leicester, between 19:00 UT on 20 jan 2017 and 00:30 on 21 jan 2017 (i.e. starting 6.5 hours after the LIGO event). These consist of shallow, many-tile, mosaics of ~1 square degree centered on some nearby galaxies from the GWGC catalogue, in particular UGC 03804 (RA=110.6,Dec=71.6), UGC 05295 (RA=142.2,Dec=42.8), and covering galaxies near those positions. No credible transient candidates brighter than V=17.0 were detected (but analysis is ongoing). In addition we observed several other GWGC catalogue sources using smaller fields of view (12x9 arc min) at a deeper limiting magnitude, e.g. NGC3009, NGC3032, UGC03804. No transient candidates brighter than V=18.5 were found near or in these galaxies. We do detect MASTER OT J090737.22+611200.5 (Lipunov et al., GCN 20488), at V~19.5 on 23:19 UT on 21 jan 2017.