TITLE: GCN CIRCULAR NUMBER: 26488 SUBJECT: LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations DATE: 19/12/18 18:31:43 GMT FROM: Dong Xu at NAOC/CAS Z.P. Zhu, B.Y. Yu, D. Xu (NAOC), X. Zhang, S.G. Ma, J.Z. Liu, H.B. Niu (XAO), H.J. Wang, L. Ge, T.M. Zhang, X. Zhou, C.Z. Cui, Y.F. Xu (NAOC), H.B. Zhao, B. Li (PMO), J.R. Mao (YNAO), X. Gao (Urumqi No.1 Senior High School) report on behalf of the GWFUNC collaboration: We observed the high-probability localization region of the LIGO/Virgo gravitational wave trigger S191216ap (GCN #26454) that can be reached by the Nanshan One-meter Wide field Telescope (NOWT) with the FOV of 1.3x1.3 deg^2. Observations started at 11:57:05 UT and ended at 15:19:31 UT on 2019-12-17 in R-band. Typical limiting depth is of ~19.0 mag, and 60 sec for each exposure. Listed below are the center coordinates of each exposure: 21:12:36.864000 +29:36:00.000000 21:18:35.424000 +29:36:00.000000 21:06:33.984000 +30:54:00.000000 21:18:40.608000 +30:54:00.000000 21:06:28.800000 +32:12:00.000000 21:12:36.864000 +32:12:00.000000 21:18:45.792000 +32:12:00.000000 21:12:19.584000 +25:42:00.000000 21:18:05.184000 +25:42:00.000000 21:23:51.648000 +25:42:00.000000 21:12:15.264000 +27:00:00.000000 21:18:05.184000 +27:00:00.000000 21:18:05.184000 +28:18:00.000000 21:23:59.424000 +28:18:00.000000 20:52:44.544000 +37:24:00.000000 21:05:50.784000 +37:24:00.000000 20:52:37.632000 +38:42:00.000000 21:05:57.696000 +38:42:00.000000 20:52:30.720000 +40:00:00.000000 20:59:17.664000 +40:00:00.000000 21:06:04.608000 +40:00:00.000000 21:06:22.752000 +21:48:00.000000 21:17:34.944000 +21:48:00.000000 21:06:18.432000 +23:06:00.000000 21:11:58.848000 +23:06:00.000000 21:06:15.840000 +24:24:00.000000 21:11:58.848000 +24:24:00.000000 21:17:40.992000 +24:24:00.000000 20:43:26.400000 +41:18:00.000000 20:50:21.984000 +41:18:00.000000 20:57:17.568000 +41:18:00.000000 20:43:17.760000 +42:36:00.000000 20:50:21.984000 +42:36:00.000000 20:57:25.344000 +42:36:00.000000 20:43:08.256000 +43:54:00.000000 20:50:21.984000 +43:54:00.000000 20:57:34.848000 +43:54:00.000000 20:47:35.232000 +33:30:00.000000 20:53:50.208000 +33:30:00.000000 21:00:04.320000 +33:30:00.000000 21:00:10.368000 +34:48:00.000000 20:47:24.864000 +36:06:00.000000 20:53:50.208000 +36:06:00.000000 21:00:16.416000 +36:06:00.000000 21:12:18.720000 +14:00:00.000000 21:17:40.992000 +14:00:00.000000 21:23:01.536000 +14:00:00.000000 21:12:16.992000 +15:18:00.000000 21:17:40.992000 +15:18:00.000000 21:23:03.264000 +15:18:00.000000 21:12:14.400000 +16:36:00.000000 21:23:05.856000 +16:36:00.000000 21:12:50.688000 +33:30:00.000000 21:19:04.800000 +33:30:00.000000 21:06:30.528000 +34:48:00.000000 21:12:50.688000 +34:48:00.000000 21:19:09.984000 +34:48:00.000000 21:06:23.616000 +36:06:00.000000 21:12:50.688000 +36:06:00.000000 21:06:28.800000 +17:54:00.000000 21:11:56.256000 +17:54:00.000000 21:17:23.712000 +17:54:00.000000 21:06:25.344000 +19:12:00.000000 21:11:56.256000 +19:12:00.000000 21:06:22.752000 +20:30:00.000000 21:22:59.808000 +17:54:00.000000 21:11:56.256000 +20:30:00.000000 21:28:27.264000 +17:54:00.000000 No credible counterpart candidate was identified in the above fields. In addition, we also imaged the localization region of the HAWC gamma-ray counterpart candidate (GCN #26472) during the searching, which is inside the localization region of the IceCube neutrino counterpart candidate (GCN #26460). Four out of nine GLADE galaxies were covered, as follows: | RAJ2000 | DEJ2000 | Dist | r_SDSS | r_NOWT | | ---------- | --------- | ----- |-------- | ---------- | | 323.482422 | +5.279632 | 274.4 | 16.50 | 16.52 | | 323.056030 | +4.832057 | 219.1 | 15.83 | 15.84 | | 323.173767 | +4.467985 | 292.5 | 16.10 | 16.20 | | 323.034882 | +4.482058 | 340.7 | 16.24 | 16.13 | All NOWT measurements are consistent with the SDSS values. Any significant optical transient within these galaxies can be ruled out. Furthermore, we imaged the HAWC region again, started at 13:09:43.0 UT on 2019-12-18, with 200 s for each exposure in R-band. Our results are as follows: | RAJ2000 | DEJ2000 | Dist | r_SDSS | r_NOWT | | ---------- | --------- | ----- |-------- | ---------- | | 323.482422 | +5.279632 | 274.4 | 16.50 | 16.51 | | 323.056030 | +4.832057 | 219.1 | 15.83 | 15.85 | | 322.921936 | +5.503483 | 232.2 | 15.57 | 15.60 | | 322.838806 | +5.255421 | 179.3 | 15.41 | 15.65 | | 322.821228 | +5.553754 | 338.7 | 15.83 | 15.70 | | 322.749084 | +5.108610 | 330.8 | 15.94 | 15.90 | | 323.173767 | +4.467985 | 292.5 | 16.10 | 16.20 | | 322.906006 | +5.850705 | 323.1 | 16.84 | 16.87 | | 323.034882 | +4.482058 | 340.7 | 16.24 | 16.12 | Again the NOWT measurements are consistent with the SDSS values. Any significant optical transient within these galaxies can be ruled out.