TITLE:   GCN CIRCULAR
NUMBER:  21073
SUBJECT: LIGO/Virgo G284239:SVOM/Mini-GWAC observations of the initial skymap
DATE:    17/05/06 08:43:48 GMT
FROM:    Chao Wu at NAOC  <wuchao.lamost@gmail.com>

L.P. Xin (NAOC), J.Y. Wei (NAOC), X.H. Han (NAOC), C. Wu (NAOC),
S. Antier (LAL), N. Leroy (LAL), X.M. Meng (NAOC), L. Huang (NAOC),
Y. Xu (NAOC), H.B. Cai (NAOC), J. Wang (NAOC), X.M. Lu (NAOC),
Y.L. Qiu (NAOC), J.S. Deng (NAOC), L. Cao (NAOC), S. Wang (NAOC),
L. Jia (NAOC), S.C. Zou (NAOC), S.F. Liu (NAOC), Q.C. Feng (NAOC),
H.L. Li (NAOC), D.W. Xu (NAOC), Y.J. Xiao (NAOC), W.L. Dong (NAOC),
Y.T. Zheng (NAOC), E.W.Liang (GXU), X.G.Wang (GXU), Y.G. Yang (HBNU),
B. Cordier (CEA), S.N. Zhang (NAOC), D. Dornic (CPPM), B.B. Wu (IHEP),
D. Turpin (IRAP), A. Klotz (IRAP), C.Lachaud (APC),
on behalf of the SVOM Gravitational Astronomy group report:

We observed about 2400 square degree (6 sky regions) of the skymap
of the advanced LIGO trigger G284239, with SVOM/Mini-GWAC, at Xinglong
Observatory of NAOC equipped with U9000 camera (FOV~400 square
degree/camera).
SVOM/Mini-GWAC comprises 12 wide field angle cameras (aperture=7cm),
working with unfiltered band. The observations are operated in time-series
mode, taking one exposure in 15 seconds (10s exposure + 5s readout).
The limit magnitude is ~12 mag in R band. We estimate a 22.0% prior
probability that these 6 regions contain the true location of the
source.

The coordinates of the 6 regions and observation time are list following:
start-obs(UTC)  end-obs(UTC)    Ra      Dec     Camera_ID
2017-05-05 12:18:07 2017-05-05 14:09:34 06:35:33.2 +70:03:11   C3
2017-05-05 14:17:02 2017-05-05 20:09:33 17:41:40.8 +30:05:48   C3
2017-05-05 12:15:52 2017-05-05 14:07:41 06:44:38.4 +49:45:43   C4
2017-05-05 14:15:38 2017-05-05 20:09:05 17:45:33.4 +10:00:59   C4
2017-05-05 12:10:29 2017-05-05 17:09:26 09:15:43.9 +69:29:34   C5
2017-05-05 19:59:14 2017-05-05 20:09:17 11:56:29.8 +69:27:40   C5
2017-05-05 12:10:29 2017-05-05 17:09:36 09:21:17.0 +50:29:41   C6
2017-05-05 17:10:50 2017-05-05 20:04:52 12:01:27.8 +50:23:40   C6
2017-05-05 12:11:12 2017-05-05 20:09:24 16:15:56.4 +29:39:59   C7
2017-05-05 12:45:41 2017-05-05 20:09:30 16:16:57.1 +10:13:56   C8

The covering map is available at:
http://svom.bao.ac.cn/svomgwpub/skymap/G284239_skymap_miniGWAC.png
(svom:gw2017@svom).

The first image was taken 2.4 days after the event trigger. The delay
is due to the bad weather.
No any significant transient is found in our online pipeline. The
image analysis is ongoing in detailed processing with our offline
pipeline to search for any transient candidate.