[vsnet-grb-info 23682] LIGO/Virgo S190915ak: No significant candidates in TAROT-GRANDMA observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25781
SUBJECT: LIGO/Virgo S190915ak: No significant candidates in TAROT-GRANDMA observations
DATE:    19/09/19 14:22:52 GMT
FROM:    Alexander Kann at IAA-CSIC  <kann at iaa.es>

D. A. Kann (HETH/IAA-CSIC), A. Simon (ASPD TSNUK), Z. Vidadi (Shao), S. 
Antier (APC), M. Boer (Artemis), N. Christensen (Artemis), L. Eymar 
(Artemis), A. Klotz (IRAP), S. Alishov (SHAO), K. Barynova (Kyiv Univ),  
D. Coward (OzGrav-UWA), K. Noysena (Artemis, IRAP),  S. Basa (LAM), D. 
Corre (LAL), M. Coughlin (Caltech), J.G. Ducoin (LAL), B. Gendre 
(OzGrav-UWA), P. Hello (LAL), C. Lachaud (APC), N. Leroy (LAL), D. 
Turpin (NAOC) and X. Wang (THU)

report on behalf of the TAROT network and GRANDMA collaborations:

We performed tiled observations of LIGO/Virgo S190915ak event (GCN 
#25753) with the TAROT-Calern (TCA) telescope operating in the visible 
located at Calern site at the Cote d'Azur observatory. The observation 
started on 09/16/19 00:12:27 UTC which corresponds approximately to 16 
minutes after the GW trigger time.

We performed the following tiled observations :

+------------+------------+---------+---------+---------+
| TStart     | TEnd       | RA      | DEC     |   Proba |
| [UTC]      | [UTC]      | [deg]   | [deg]   |     [%] |
|------------+------------+---------+---------+---------|
| 2019-09-16 | 2019-09-16 | 195.545 | 68.682  |     1.0 |
| 00:12:27   | 23:06:42   |         |         |         |
| 2019-09-16 | 2019-09-16 | 187.785 | 66.826  |     0.7 |
| 00:19:13   | 23:13:29   |         |         |         |
| 2019-09-16 | 2019-09-18 | 190.68  | 68.682  |     1.1 |
| 00:54:58   | 01:52:26   |         |         |         |
| 2019-09-16 | 2019-09-17 | 185.815 | 68.682  |     0.5 |
| 01:20:35   | 01:17:26   |         |         |         |
| 2019-09-16 | 2019-09-18 | 192.342 | 66.826  |     1.6 |
| 01:27:23   | 03:10:13   |         |         |         |
| 2019-09-16 | 2019-09-16 | 186.244 | 70.538  |     0.4 |
| 01:34:07   | 22:57:41   |         |         |         |
| 2019-09-16 | 2019-09-17 | 191.538 | 70.538  |     0.8 |
| 02:51:43   | 01:10:45   |         |         |         |
| 2019-09-16 | 2019-09-17 | 168.392 | 77.96   |     0.2 |
| 23:58:22   | 00:04:42   |         |         |         |
| 2019-09-17 | 2019-09-18 | 195.774 | 64.971  |     1.9 |
| 00:05:13   | 02:57:21   |         |         |         |
| 2019-09-17 | 2019-09-17 | 161.664 | 74.249  |     0.1 |
| 00:17:49   | 02:54:26   |         |         |         |
| 2019-09-17 | 2019-09-17 | 196.899 | 66.826  |     1.3 |
| 00:24:37   | 21:01:18   |         |         |         |
| 2019-09-17 | 2019-09-17 | 191.538 | 64.971  |     1.5 |
| 02:15:22   | 20:54:35   |         |         |         |
| 2019-09-17 | 2019-09-17 | 180.95  | 68.682  |     0.4 |
| 02:41:18   | 02:47:37   |         |         |         |
| 2019-09-17 | 2019-09-17 | 196.541 | 50.125  |     5.3 |
| 19:19:28   | 21:40:15   |         |         |         |
| 2019-09-17 | 2019-09-17 | 195.704 | 51.981  |     4.9 |
| 19:30:30   | 19:34:40   |         |         |         |
| 2019-09-17 | 2019-09-17 | 193.706 | 50.125  |     2.1 |
| 20:16:20   | 20:22:40   |         |         |         |
| 2019-09-17 | 2019-09-17 | 196.832 | 46.414  |     1.7 |
| 20:28:50   | 20:35:09   |         |         |         |
| 2019-09-17 | 2019-09-17 | 194.796 | 63.115  |     1.5 |
| 20:41:28   | 20:47:47   |         |         |         |
| 2019-09-17 | 2019-09-17 | 197.021 | 55.692  |     1.3 |
| 21:01:43   | 21:08:03   |         |         |         |
| 2019-09-17 | 2019-09-17 | 192.753 | 51.981  |     1.1 |
| 21:13:51   | 21:20:10   |         |         |         |
| 2019-09-17 | 2019-09-17 | 200.95  | 53.837  |     1.1 |
| 21:20:24   | 21:26:44   |         |         |         |
| 2019-09-17 | 2019-09-17 | 198.655 | 51.981  |     4.2 |
| 21:46:35   | 21:52:54   |         |         |         |
| 2019-09-17 | 2019-09-17 | 197.873 | 53.837  |     3.3 |
| 21:53:19   | 21:59:38   |         |         |         |
+------------+------------+---------+---------+---------+

TStart and TEnd refers respectively to the time of the first and last 
exposure for a given tile. Observations are not necessarily continuous 
in this interval.

The Probability refers to the 2D spatial probability of the GW skymap 
enclosed in a given tile. Each tile is 1.9x1.9 degrees. These 
observations cover about 36% the cumulative probability of the 
LALInference skymap available on Sep 17, 2019 14:16:39 UTC.

The typical limiting magnitude is 18.0 for a 60.0 s exposure.

The coverage map is available at: 
https://grandma-owncloud.lal.in2p3.fr/index.php/s/55vKDfmLJzbHyBn

No significant transient candidates were found during our low latency 
analysis.

GRANDMA (Global Rapid Advanced Network Devoted to the Multi-messenger 
Addicts) is a network of robotic telescopes connected all over the world 
with both photometry and spectroscopy capabilities for Time-domain 
Astronomy (https://grandma.lal.in2p3.fr/). Details on the TCA telescope  
are available on the GRANDMA web pages or on  http://tarot.obs-hp.fr/.