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GCN Circular 25593

Subject
LIGO/Virgo S190828l: No significant candidates in TAROT-GRANDMA observations
Date
2019-08-31T21:07:20Z (5 years ago)
From
Nelson Christensen at Obs.de la Cote dAzur,Nice <nelson.christensen@oca.eu>
S. Antier (APC), C. Lachaud (APC), N. Christensen (Artemis), B. Gendre 
(OzGrav-UWA), N. Ismayilov (SHAO), M. Boer (Artemis), L. Eymar 
(Artemis), A. Klotz (IRAP), K. Noysena (Artemis, IRAP), S. Basa (LAM), 
D. Corre (LAL), M. Coughlin (Caltech), D. Coward (OzGrav-UWA), J.G. 
Ducoin (LAL), P. Hello (LAL), N. Leroy (LAL), D. Turpin (NAOC), X. Wang 
(THU) report on behalf of the TAROT network and GRANDMA collaborations.

We performed tiled observations of the LIGO/Virgo event S190828l with 
the TAROT-Chili (TCH), TAROT-Calern (TCA) and TAROT-Reunion (TRE) 
telescopes operating in the visible located respectively at La Silla ESO 
Observatory (LaS/ESO), Calern site at the Cote d'Azur Observatory and 
Les Makes astronomical Observatory.


The observation started for TCH on 08/28/19 08:08:26 UTC which 
corresponds to approximately 74 minutes after the GW trigger time.

We performed the following tiled observations :

+-------+------------+------------+---------+---------+---------+
| Tele  | TStart     | TEnd       | RA      | DEC     |   Proba |
| scope | [UTC]      | [UTC]      | [deg]   | [deg]   |     [%] |
|-------+------------+------------+---------+---------+---------|
|  TCH  | 2019-08-28 | 2019-08-30 | 155.236 | -61.777 |     0.5 |
|       | 08:08:26   | 09:29:11   |         |         |         |
|  TCH  | 2019-08-28 | 2019-08-29 | 157.656 | -63.595 |     0.5 |
|       | 08:15:15   | 23:35:28   |         |         |         |
|  TCH  | 2019-08-28 | 2019-08-30 | 149.185 | -58.141 |     0.5 |
|       | 08:22:03   | 09:41:21   |         |         |         |
|  TCH  | 2019-08-28 | 2019-08-30 | 159.192 | -61.777 |     0.5 |
|       | 08:28:51   | 09:48:09   |         |         |         |
|  TCH  | 2019-08-28 | 2019-08-30 | 160.538 | -59.959 |     0.3 |
|       | 09:06:48   | 00:27:25   |         |         |         |
|  TCH  | 2019-08-28 | 2019-08-29 | 163.148 | -61.777 |     0.3 |
|       | 08:51:18   | 09:33:23   |         |         |         |
|  TCH  | 2019-08-28 | 2019-08-30 | 153.421 | -63.595 |     0.3 |
|       | 08:58:06   | 00:39:41   |         |         |         |
|  TCH  | 2019-08-28 | 2019-08-28 | 152.715 | -58.141 |     0.8 |
|       | 09:29:56   | 09:58:42   |         |         |         |
|  TCH  | 2019-08-28 | 2019-08-30 | 153.115 | -59.959 |     0.7 |
|       | 09:36:44   | 09:08:47   |         |         |         |
|  TCH  | 2019-08-28 | 2019-08-30 | 156.244 | -58.141 |     0.6 |
|       | 10:14:23   | 09:22:23   |         |         |         |
|  TCH  | 2019-08-28 | 2019-08-30 | 151.28  | -61.777 |     0.3 |
|       | 08:37:52   | 00:20:37   |         |         |         |
|  TCH  | 2019-08-28 | 2019-08-30 | 166.126 | -63.595 |     0.2 |
|       | 23:39:52   | 00:46:29   |         |         |         |
|  TCH  | 2019-08-28 | 2019-08-30 | 167.45  | -65.414 |     0.2 |
|       | 23:46:40   | 00:53:17   |         |         |         |
|  TCH  | 2019-08-29 | 2019-08-30 | 156.826 | -59.959 |     0.6 |
|       | 00:39:07   | 09:15:35   |         |         |         |
|  TCH  | 2019-08-29 | 2019-08-30 | 162.95  | -65.414 |     0.4 |
|       | 01:37:16   | 00:13:48   |         |         |         |
|  TCH  | 2019-08-29 | 2019-08-30 | 153.95  | -65.414 |     0.2 |
|       | 00:01:13   | 08:35:31   |         |         |         |
|  TCH  | 2019-08-29 | 2019-08-30 | 158.45  | -65.414 |     0.4 |
|       | 01:24:45   | 10:01:45   |         |         |         |
|  TCH  | 2019-08-29 | 2019-08-29 | 149.404 | -59.959 |     0.4 |
|       | 09:00:58   | 09:07:28   |         |         |         |
|  TCH  | 2019-08-29 | 2019-08-30 | 161.49  | -67.232 |     0.2 |
|       | 09:52:35   | 01:00:05   |         |         |         |
|  TCH  | 2019-08-29 | 2019-08-30 | 161.891 | -63.595 |     0.5 |
|       | 01:17:57   | 09:54:57   |         |         |         |
|-------+------------+------------+---------+---------+---------|
|  TCA  | 2019-08-28 | 2019-08-28 | -0.95   | 40.372  |     0.3 |
|       | 19:25:55   | 19:32:26   |         |         |         |
|  TCA  | 2019-08-28 | 2019-08-29 | 356.118 | 39.897  |     0.2 |
|       | 19:32:44   | 00:38:48   |         |         |         |
|  TCA  | 2019-08-28 | 2019-08-30 | 20.793  | 50.125  |     0.2 |
|       | 19:39:35   | 01:45:21   |         |         |         |
|  TCA  | 2019-08-28 | 2019-08-28 | 358.467 | 42.228  |     0.2 |
|       | 20:11:14   | 20:17:43   |         |         |         |
|  TCA  | 2019-08-28 | 2019-08-28 | 5.915   | 42.703  |     0.1 |
|       | 20:18:03   | 20:24:35   |         |         |         |
|  TCA  | 2019-08-28 | 2019-08-30 | 21.606  | 51.981  |     0.1 |
|       | 20:24:55   | 02:30:44   |         |         |         |
|  TCA  | 2019-08-28 | 2019-08-29 | 6.056   | 44.558  |     0.1 |
|       | 21:16:04   | 22:22:35   |         |         |         |
|  TCA  | 2019-08-28 | 2019-08-29 | 22.768  | 48.27   |     0.1 |
|       | 21:22:55   | 22:29:26   |         |         |         |
|  TCA  | 2019-08-28 | 2019-08-29 | 3.503   | 44.558  |     0.1 |
|       | 21:29:46   | 22:36:15   |         |         |         |
|  TCA  | 2019-08-28 | 2019-08-30 | 3.433   | 42.703  |     0.2 |
|       | 22:21:49   | 01:59:03   |         |         |         |
|  TCA  | 2019-08-28 | 2019-08-28 | 0.95    | 42.703  |     0.2 |
|       | 22:28:37   | 22:35:08   |         |         |         |
|  TCA  | 2019-08-28 | 2019-08-28 | 4.357   | 40.847  |     0.2 |
|       | 22:35:30   | 22:42:00   |         |         |         |
|  TCA  | 2019-08-28 | 2019-08-28 | 18.655  | 51.981  |     0.1 |
|       | 23:26:38   | 23:33:08   |         |         |         |
|  TCA  | 2019-08-28 | 2019-08-29 | 355.985 | 41.753  |     0.1 |
|       | 23:33:27   | 19:39:36   |         |         |         |
|  TCA  | 2019-08-28 | 2019-08-29 | 23.627  | 50.125  |     0.1 |
|       | 23:40:17   | 19:44:12   |         |         |         |
|  TCA  | 2019-08-29 | 2019-08-30 | 1.941   | 40.847  |     0.2 |
|       | 00:46:00   | 01:52:12   |         |         |         |
|  TCA  | 2019-08-29 | 2019-08-30 | 20.041  | 48.27   |     0.1 |
|       | 01:31:03   | 02:37:35   |         |         |         |
|  TCA  | 2019-08-29 | 2019-08-29 | 17.958  | 50.125  |     0.1 |
|       | 01:37:52   | 21:42:04   |         |         |         |
|  TCA  | 2019-08-29 | 2019-08-29 | 353.702 | 39.897  |     0.1 |
|       | 21:44:38   | 21:51:09   |         |         |         |
|-------+------------+------------+---------+---------+---------|
|  TRE  | 2019-08-28 | 2019-08-28 | 331.034 | 8.182   |     0.4 |
|       | 21:08:23   | 21:14:51   |         |         |         |
|  TRE  | 2019-08-28 | 2019-08-28 | 338.571 | 16.364  |     0.4 |
|       | 21:21:39   | 21:28:07   |         |         |         |
|  TRE  | 2019-08-28 | 2019-08-29 | 354.857 | 36.818  |     1.2 |
|       | 22:02:37   | 20:39:07   |         |         |         |
|  TRE  | 2019-08-28 | 2019-08-29 | 330     | 16.364  |     0.3 |
|       | 23:57:44   | 00:04:12   |         |         |         |
|  TRE  | 2019-08-29 | 2019-08-29 | 350.27  | 32.727  |     1.4 |
|       | 00:26:17   | 00:32:45   |         |         |         |
|  TRE  | 2019-08-29 | 2019-08-29 | 342     | 24.545  |     1.1 |
|       | 00:39:00   | 00:45:28   |         |         |         |
|  TRE  | 2019-08-29 | 2019-08-29 | 330.698 | 12.273  |     0.7 |
|       | 16:23:40   | 16:30:08   |         |         |         |
|  TRE  | 2019-08-29 | 2019-08-29 | 333.659 | 20.455  |     0.5 |
|       | 16:41:25   | 16:43:25   |         |         |         |
|  TRE  | 2019-08-29 | 2019-08-29 | 345.974 | 28.636  |     1.1 |
|       | 20:45:52   | 20:52:26   |         |         |         |
+-------+------------+------------+---------+---------+---------+


TStart and TEnd refer 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 
for TCA and TCH and 4.2x4.2 degrees for TRE. The coordinating 
observations cover about 18% of the cumulative probability of the 
bayestar skymap available on Aug 28, 2019 07:17:33 UTC. The typical 
limiting magnitude is 18.0 for a 60.0 s exposure for TCH and TCA and 
17.0 for a 60.0 s exposure for TRE.

The coverage map is available at:
https://grandma-owncloud.lal.in2p3.fr/index.php/s/JF7J7CIdlrc7qs1

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 spectrometry capabilities for Time-domain 
Astronomy (https://grandma.lal.in2p3.fr/). Details on the TAROT 
telescope  are available on the GRANDMA web pages
or on
http://tarot.obs-hp.fr/.
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