TITLE: GCN CIRCULAR NUMBER: 24182 SUBJECT: LIGO/Virgo S190425z: MMT Follow-Up Observations DATE: 19/04/25 14:26:34 GMT FROM: Griffin Hosseinzadeh at Harvard U G. Hosseinzadeh, E. Berger, P. K. Blanchard, T. Eftekhari, J. Gill, S. Gomez, L. Patton, V. A. Villar, P. K. G. Williams (Harvard U), P. S. Cowperthwaite (Carnegie Obs), R. Chornock (Ohio U), W. Fong, R. Margutti (Northwestern U), and M. Nicholl (U Edinburgh) report: We obtained 30 s g-band images of the following galaxies in the LIGO/Virgo localization region of S190425z with the MMTCam instrument on the MMT 6.5-m telescope: Name R.A. Dec. Date UT 16545364-1657072 253.723525833333 -16.952021 2019-04-25 11:39:23.06 16571426-0613510 254.309417916667 -6.230837 2019-04-25 11:42:29.66 16520774-1703135 253.032287916667 -17.053755 2019-04-25 11:44:21.54 16590728-0544311 254.780334166667 -5.741986 2019-04-25 11:45:55.20 16580128-0149216 254.505370833333 -1.822693 2019-04-25 11:47:32.92 NGC6234 252.988937083333 4.383557 2019-04-25 11:49:28.05 59064 252.388167916667 6.016252 2019-04-25 11:51:21.12 59201 253.350372083333 4.23625 2019-04-25 11:52:39.44 16564688-0142052 254.195357916667 -1.701466 2019-04-25 11:54:11.67 UGC10426 247.709015 16.250687 2019-04-25 11:57:26.92 90265.0 254.36174 -10.191098 2019-04-25 11:59:13.75 NGC6225 252.08989 6.222765 2019-04-25 12:00:51.40 16462248+0902154 251.593704166667 9.037632 2019-04-25 12:02:05.10 16552449-0715255 253.852080833333 -7.25709 2019-04-25 12:04:56.52 Comparison of the images to the PS1 3pi survey (Chambers et al. 2016, arXiv:1612.05560) reveals no new sources brighter than ~21 mag. We thank Mike Calkins and Ben Kunk at MMT for taking these observations.