LIGO/Virgo S190425z: RATIR non-detection of the Swift/UVOT source. Troja, E. ; Watson, A. M. ; Becerra, R. L. ; Butler, N. ; Gonzalez, D. ; Kutyrev, A. ; Lee, W. H. ; Pereyra, M. ; Wolfram, T. Abstract Publication: GRB Coordinates Network Pub Date: 2019 Bibcode: 2019GCN.24335....1T