TITLE:   GCN CIRCULAR
NUMBER:  24431
SUBJECT: LIGO/Virgo S190503bf: TAROT-GRANDMA observation report
DATE:    19/05/09 09:03:24 GMT
FROM:    Nelson Christensen at Obs.de la Cote dAzur,Nice  <nelson.christensen@oca.eu>

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

report on behalf of the TAROT network and GRANDMA collaboration.

We performed tiled observations of LIGO/Virgo S190503bf event with the
TAROT-Chili telescope operating in clear filter.

The observation started on 05/03/19 23:16:23 UTC which corresponds
approximately to 263 minutes after the GW trigger time.

We performed the following tiled observations :

+------------+------------+---------+---------+---------+
| TStart     | TEnd       | RA      | DEC     |   Proba |
| [UTC]      | [UTC]      | [deg]   | [deg]   |     [%] |
|------------+------------+---------+---------+---------|
| 2019-05-03 | 2019-05-04 | 97.627  | -53.636 |     2.3 |
| 23:16:23   | 03:34:12   |         |         |         |
| 2019-05-03 | 2019-05-04 | 95.575  | -55.455 |     2.2 |
| 23:23:12   | 03:41:00   |         |         |         |
| 2019-05-03 | 2019-05-04 | 94.576  | -53.636 |     3   |
| 23:30:01   | 03:59:07   |         |         |         |
| 2019-05-03 | 2019-05-04 | 96.585  | -51.818 |     2.6 |
| 23:42:26   | 03:14:59   |         |         |         |
| 2019-05-03 | 2019-05-03 | 95.625  | -50     |     2.5 |
| 23:49:15   | 23:55:45   |         |         |         |
| 2019-05-03 | 2019-05-04 | 92.812  | -50     |     2.4 |
| 23:56:03   | 03:27:25   |         |         |         |
| 2019-05-04 | 2019-05-04 | 93.659  | -51.818 |     2.9 |
| 00:21:32   | 03:08:10   |         |         |         |
+------------+------------+---------+---------+---------+


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 17% of the cumulative probability of the skymap.

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/9MO62YiDroG6GU6

According to our data analysis, no serious optical transient candidates
were found.

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
telescopes are available on the GRANDMA web pages or on
http://tarot.obs-hp.fr/


This circular is citable.