[vsnet-grb-info 24389] LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations

[GCN Circulars]

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  <dxu at nao.cas.cn>

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.