TITLE: GCN CIRCULAR NUMBER: 24192 SUBJECT: LIGO/Virgo S190425z: J-GEM optical follow-up observations with Subaru/FOCAS DATE: 19/04/25 17:56:25 GMT FROM: Mahito Sasada at Hiroshima University Sasada, M., Akitaya, H., Nakaoka, T. (Hiroshima U.), Yoshida, M. (NAOJ/Subaru), Tanaka, M. (Tohoku U.), Tominaga N., Ohgami, T., Kaneko A. (Konan U.), Itoh, R. (Bisei Astronomical Observatory), Sekiguchi, Y. (Toho U.), Utsumi, Y. (Stanford U./SLAC), Morokuma, T., Niino, Y., Ohsawa, R. (U. of Tokyo), Murata, K. L. (Tokyo Tech), on behalf of J-GEM collaboration We report our optical imaging observations of galaxies in the localization region of the BNS gravitational wave event S190425z (The LIGO Scientific Collaboration and the Virgo Collaboration, 2019, GCN, 24168) using the Faint Object Camera and Spectrograph (FOCAS; 6 arcmin field-of-view in diameter; Kashikawa et al. 2002, PASJ, 54, 819) on the 8.2-m Subaru telescope. We started our observations at UT 2019-04-25 11:46, about 3.5 hours after the event. We observed 154 galaxies in total. The target galaxies are selected from the list of potential host galaxies for this event (Dalya et al. 2019, GCN, 24171) around the central coordinate of the localization of the gamma-ray pulses detected with INTEGRAL/SPI-ACS (Minaev et al. 2019, GCN, 24170). The list of the galaxies we observed is shown in the table below. We took ten-second r-band images for each galaxy with typical 5-sigma depths of 23-24 mag. The obtained images are compared with the Pan-STARRS r-band images (Chambers et al., 2016, arXiv:1612.05560) with similar or slightly shallower depths compared to our FOCAS images. In these galaxies, we find no apparent transient objects that are not registered in the IAU Transient Name Server (https://wis-tns.weizmann.ac.il). Galaxy name RA Dec 2MASS16522624+2319575 16:52:26.24 +23:19:57.5 NGC6051 16:04:56.70 +23:55:58.3 NGC6062 16:06:22.80 +19:46:40.6 60191 17:23:26.11 +23:38:39.5 NGC6308 17:11:59.72 +23:22:48.3 57296 16:09:15.67 +25:42:45.0 56144 15:49:57.32 +20:48:18.6 UGC10138 16:01:40.23 +21:21:10.6 UGC10153 16:03:19.52 +20:38:12.5 57607 16:14:57.83 +21:56:17.9 58028 16:24:15.15 +20:11:00.9 56443 15:56:33.64 +20:03:08.2 56713 16:01:28.67 +22:25:39.6 NGC6203 16:40:27.38 +23:46:29.1 57072 16:05:29.16 +19:56:31.7 2MASS16313806+2047366 16:31:38.06 +20:47:36.6 58396 16:30:47.15 +20:21:19.3 NGC6233 16:50:15.72 +23:34:47.4 1683153 16:32:58.94 +23:11:51.0 1745822 16:09:51.84 +25:41:11.6 59087 16:50:14.26 +23:26:28.4 58322 16:29:17.35 +20:21:53.3 58537 16:34:53.70 +23:12:42.2 UGC10224 16:08:50.23 +22:02:33.4 2MASS18405128+2334077 18:40:51.28 +23:34:07.7 58006 16:23:40.08 +24:28:26.6 1695642 16:22:57.30 +23:53:35.9 1631905 16:16:11.90 +20:36:45.1 UGC10834 17:24:32.84 +20:23:53.0 1612380 16:00:30.52 +19:59:07.0 55776 15:40:37.22 +20:33:44.7 56150 15:49:59.28 +20:48:20.6 UGC10260 16:11:57.87 +20:55:24.4 NGC6075 16:11:22.56 +23:57:54.5 57272 16:08:33.84 +21:04:52.3 1635109 15:44:24.00 +20:45:09.5 214459 16:06:00.72 +20:50:50.2 2MASS16060593+2047032 16:06:05.93 +20:47:03.2 2MASS16072060+2058306 16:07:20.60 +20:58:30.6 3089913 16:06:16.28 +21:03:49.2 PGC1626696 12:03:48.25 +20:24:58.9 56856 16:03:17.78 +21:35:30.5 56706 16:01:25.27 +21:55:57.5 1661347 16:04:50.77 +21:59:23.3 214390 15:35:04.81 +23:28:45.7 56084 15:48:33.88 +22:58:20.8 57085 16:05:36.81 +22:11:10.8 56652 16:00:38.21 +22:32:37.0 57526 16:13:25.54 +21:54:33.8 SDSSJ153858.32+234650.8 15:38:58.33 +23:46:50.8 2MASS16073961+2220315 16:07:39.61 +22:20:31.5 1671243 16:05:23.40 +22:30:27.6 IC4573 15:42:12.27 +23:48:00.5 57116 16:05:58.62 +22:37:55.9 57420 16:11:20.97 +22:22:31.3 56853 16:03:13.71 +23:00:29.5 UGC10236 16:10:05.09 +22:39:01.1 56252 15:52:02.13 +23:44:02.7 UGC10066 15:51:36.87 +23:47:24.1 1688132 16:03:44.45 +23:28:55.4 57542 16:13:46.01 +22:55:07.9 57472 16:12:20.33 +23:00:07.0 56175 15:50:38.65 +20:22:54.7 1623900 16:04:43.49 +20:19:25.3 56534 15:58:33.94 +20:11:06.3 UGC10060 15:51:06.90 +20:12:09.2 3089914 16:18:24.75 +20:53:23.9 1686786 15:10:28.49 +23:24:14.4 PGC1689724 15:11:16.57 +23:34:20.9 2MASS16182990+2209489 16:18:29.90 +22:09:48.9 1684230 15:50:20.24 +23:15:32.7 1690340 15:43:51.42 +23:36:26.5 1668320 16:19:07.19 +22:21:07.7 55690 15:38:59.04 +23:46:54.0 1672257 16:17:11.69 +22:33:46.9 57493 16:12:42.77 +22:59:02.7 2MASS16141210+2307136 16:14:12.10 +23:07:13.6 57263 16:08:23.52 +23:28:24.7 57265 16:08:22.57 +23:28:46.7 56963 16:04:36.61 +23:39:47.3 1691288 16:04:59.95 +23:39:30.4 57021 16:05:02.50 +23:40:08.5 56958 16:04:33.46 +23:50:16.3 57003 16:04:50.57 +23:58:30.3 57014 16:04:59.47 +23:58:12.3 56887 16:03:41.89 +24:05:42.5 1692398 16:12:07.70 +23:43:04.9 UGC10256 16:11:30.77 +23:48:42.3 56991 16:04:46.81 +24:16:43.2 1694999 16:12:14.17 +23:51:28.9 57105 16:05:49.61 +24:10:32.8 1705857 16:03:14.25 +24:22:23.2 57406 16:11:14.38 +24:13:29.5 1717114 16:04:16.27 +24:48:44.4 UGC10160 16:03:54.24 +25:00:38.0 57029 16:05:11.46 +24:57:36.7 56949 16:04:35.57 +25:11:23.3 57293 16:09:06.46 +24:52:13.0 1686035 16:36:40.62 +23:21:36.5 58712 16:39:41.29 +23:30:53.4 58345 16:29:44.04 +23:21:10.6 UGC10320 16:18:07.32 +21:03:58.9 58744 16:40:50.93 +23:39:34.0 58371 16:30:13.32 +23:04:11.1 58050 16:24:45.01 +23:57:54.3 58363 16:30:02.71 +23:21:16.1 56249 15:52:05.66 +20:08:42.7 58360 16:29:53.36 +20:13:57.6 60508 17:34:06.29 +23:31:09.2 1642211 16:21:09.60 +21:04:30.3 56874 16:03:28.01 +20:17:32.3 PGC058850 16:43:36.19 +20:13:53.8 1621936 16:47:43.70 +20:15:48.6 56961 16:04:35.71 +25:43:14.3 57893 16:21:04.24 +21:20:26.3 NGC6201 16:40:14.41 +23:45:55.0 58042 16:24:34.15 +21:11:41.3 2MASS15503893+2023227 15:50:38.93 +20:23:22.7 1736488 16:10:48.42 +25:26:12.6 60430 17:31:15.29 +23:35:01.8 1614726 15:57:32.18 +20:03:12.8 57765 16:18:05.32 +21:33:12.9 NGC6062B 16:06:18.93 +19:45:47.2 58415 16:31:06.58 +23:49:57.7 1673429 16:20:44.20 +22:38:00.7 2MASS16345531+2034432 16:34:55.31 +20:34:43.2 2MASS16320391+2045519 16:32:03.91 +20:45:51.9 57752 16:17:49.42 +20:41:28.9 1638586 16:27:04.49 +20:54:35.2 1685163 16:33:32.29 +23:18:43.4 57391 16:10:52.39 +22:37:32.2 1603948 16:13:55.38 +19:44:45.9 56282 15:52:43.13 +20:13:59.8 1692904 16:52:11.03 +23:44:39.6 UGC10525 16:44:04.21 +23:23:52.1 60413 17:30:34.99 +23:37:28.9 57290 16:09:07.26 +21:52:03.7 59153 16:52:17.31 +23:18:01.5 2MASS16302400+2026011 16:30:24.00 +20:26:01.1 1667049 16:02:25.59 +22:17:02.5 59213 16:53:53.83 +20:35:51.8 1628794 16:25:52.24 +20:29:19.8 57283 16:08:58.14 +19:49:25.5 1657664 16:19:02.35 +21:48:22.7 1632425 16:25:00.27 +20:38:04.5 1612760 15:57:33.04 +19:59:43.8 1688390 16:29:48.38 +23:29:45.6 1664646 16:05:13.92 +22:09:32.6 1610658 16:05:32.29 +19:56:04.8 1727092 16:11:38.16 +25:09:11.6 1736885 16:03:52.36 +25:26:48.6 2MASS16282647+2341107 16:28:26.47 +23:41:10.7 3089915 16:20:34.24 +21:12:08.7 1699245 16:11:35.70 +24:04:35.6