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GCN Circular 21883

Subject
LIGO/Virgo G298048: AST3-2 observations of SSS17a/DLT17ck from Antarctica
Date
2017-09-15T03:45:21Z (7 years ago)
From
Igor Andreoni at Swinburne U of Tech <igor.andreoni@gmail.com>
Lei Hu (Purple Mountain Observatory), Lifan Wang (Texas A&M University/Purple Mountain Observatory), Tianrui Sun (Purple Mountain Observatory), Ma Bin (National Astronomical Observatory of China), Xiaofeng Wang (Tsinghua University), Xuefeng Wu (Purple Mountain Observatory), and the AST3 team
and
Jeff Cooke (Swinburne/OzGrav), Igor Andreoni (Swinburne/OzGrav/AAO) on behalf of OzGrav

We report observations of the GW counterpart SSS17a/DLT17ck (e.g., Coulter et al., LVC GCN 21529; Allam et al., LVC GCN 21530; Yang et al., LVC GCN 21531) with the second of Antarctica Schmidt Telescopes (AST3-2).  AST3-2 is a 50cm optical telescope located at Kunlun Station at Dome A in the Antarctic.  

Observations were carried out from August 18 through August 28 in g-band filter.  Data transfer from Antarctica has recently completed.  A source with g-band magnitude 18.15 +/-0.1 was detected on  2017-08-18T14:42.6796 (mean value) at the position of SSS17a/DLT17ck.  Note the signal was identified from a coadded image and the observational information about the component images are as follows.

Image-ID    UT datetime of start of observation     Exposure time
0818-48         '2017-08-18T13:58:11.6138'                  300.00
0818-49         '2017-08-18T14:03:14.8497'                  300.00
0818-50         '2017-08-18T14:09:07.4807'                  300.00
0818-51         '2017-08-18T14:14:10.7166'                  300.00
0818-52         '2017-08-18T14:28:36.9730'                  300.00

All observation from AST3-2 are reported below.  All time mentioned is UT time of start of exposure:

August 18 
The observation is not regular, so we list them in details

Group1: observation started from [ID 48]2017-08-18T13:58:11.6138 to [ID 51]2017-08-18T14:14:10.7166
Total 4 images with constant exposure time 300s and regular cadence about 54s
Group2: observation started from [ID 52]2017-08-18T14:28:36.9730 to [ID 72]2017-08-18T17:57:39.5806
Total 21 images with constant exposure time 300s and regular cadence about 54s

August 20 
observation started from [ID 15]2017-08-20T12:51:40.934 to [ID 74]2017-08-20T18:43:29.7538 
Total 60 images with constant exposure time 300s and regular cadence about 54s

August 21 
observation started from [ID 6]2017-08-21T13:10:22.4063 to [ID 55]2017-08-21T17:58:16.8969 
Total 50 images with constant exposure time 300s and regular cadence about 54s

August 23 
observation started from [ID 692]2017-08-23T13:13:02.8477 to [ID 722]2017-08-23T16:10:14.0793
Total 31 images with constant exposure time 300s and regular cadence about 54s

August 24
observation started from [ID 871]2017-08-24T15:52:00.3374 to [ID 917]2017-08-24T20:36:43.9922
Total 47 images with constant exposure time 300s and regular cadence about 54s

August 25
observation started from [ID 1153]2017-08-25T14:07:25.7058 to [ID 1168]2017-08-25T15:36:08.5704
Total 16 images with constant exposure time 300s and regular cadence about 54s

August 27
observation started from [ID 1204]2017-08-27T13:50:45.9777 to [ID 1223]2017-08-27T15:43:31.4251
Total 20 images with constant exposure time 300s and regular cadence about 54s

August 28
observation started from [ID 731]2017-08-28T15:12:09.9744 to [ID 738]2017-08-28T15:52:53.1212
Total 8 images with constant exposure time 300s and regular cadence about 54s

Processing of the AST3-2 images is in progress.
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