TITLE: GCN CIRCULAR NUMBER: 24314 SUBJECT: LIGO/Virgo S190425z: Liverpool Telescope imaging of ZTF19aasckkq DATE: 19/04/28 00:46:18 GMT FROM: Daniel Perley at Liverpool JMU D. A. Perley, C. M. Copperwheat, and K. L. Taggart (LJMU) report on behalf of the Global Relay of Observatories Watching Transients Happen (GROWTH) collaboration: We acquired a series of 60-second exposures of ZTF19aasckkq (Anand et al., GCN 24311), an optical transient in the error region of LIGO/Virgo S190425z (GCN 24168), using the IO:O imager on the 2m Liverpool Telescope in the u, g, r, i, and z filters between 03:17:56 and 03:30:00 UT on 2019-04-27. The transient is detected with the following magnitudes (measured after image subtraction and calibrated relative to PS1): JD magnitude 2458600.6384 g = 20.66 +/- 0.18 2458600.6395 r = 20.37 +/- 0.17 2458600.6406 i = 20.28 +/- 0.23 2458600.6416 z = 20.09 +/- 0.38 It is not detected in u-band. These suggest a moderately but not extremely red transient and show no obvious evolution relative to the ZTF imaging on 2019-04-26 (g = 20.86 +/- 0.18). DisclaimerNone