TITLE: GCN CIRCULAR NUMBER: 24126 SUBJECT: LIGO/Virgo S190412m: TAROT-GRANDMA observation report. DATE: 19/04/16 16:36:40 GMT FROM: Michel Boer at CNRS/ARTEMIS M. Boer, N. Christensen, L. Eymar (CNRS-UCA-OCA ARTEMIS), A. Klotz, K. Noysena (CNRS-UPS IRAP), S. Antier (CNRS-CEA-UP7 APC), S. Basa (CNRS-LAM), D. Corre (CNRS-UPSud LAL), M. Coughlin (Caltech), D. Coward (OzGrav-UWA),  J.-G. Ducoin (CNRS-UPSud LAL), B. Gendre (OzGrav-UWA), P. Hello (CNRS-UPSud LAL), C. Lachaud (CNRS-CEA-UP7 APC), N. Leroy (CNRS-UPSud LAL), D. Turpin (NAOC) report on behalf of the TAROT and GRANDMA collaborations. We performed tiled observations of LIGO-Virgo S190412m (GCNC #24098) event with the TCA (Calern Observatory, OCA, France) and TRE (Les Makes Observatory, La Réunion Island, France) telescopes in Clear filter. The observations started at 2019-04-12 15:39:00 UTC, about 10h after the GW trigger time. We performed the following tiled observations : For TRE +-------------------+---------------------+--------+-------+-------+ Tstart              | Tend                | RA     | DEC   | Proba | [UTC time]          | [UTC time]          | [deg]  | [deg] | [%] | +-------------------+---------------------+--------+-------+-------| 2019-04-12 18:39:12 | 2019-04-12 22:48:35 | 216.00 | 34.29 | 20.97 | 2019-04-12 18:48:00 | 2019-04-12 22:57:29 | 221.14 | 34.29 | 14.50 | 2019-04-12 19:51:03 | 2019-04-12 23:06:35 | 226.29 | 34.29 | 9.70 | 2019-04-12 18:03:00 | 2019-04-12 23:15:35 | 214.05 | 30.00 | 9.50 | 2019-04-12 16:44:21 | 2019-04-12 21:18:29 | 195.56 | 17.14 | 7.22 | 2019-04-12 15:39:01 | 2019-04-12 22:30:40 | 190.84 | 12.86 | 6.65 | 2019-04-12 15:52:37 | 2019-04-12 22:39:34 | 191.11 | 17.14 | 4.89 | +-------------------+---------------------+--------+-------+-------+ For TCA +-------------------+---------------------+--------+-------+-------+ Tstart              | Tend                | RA     | DEC   | Proba | [UTC time]          | [UTC time]          | [deg]  | [deg] | [%] | +-------------------+---------------------+--------+-------+-------| 2019-04-12 21:36:03 | 2019-04-13 02:57:34 | 214.70 | 33.64 | 7.23 | 2019-04-12 19:39:05 | 2019-04-13 03:06:35 | 213.02 | 31.82 | 6.49 | 2019-04-12 19:48:05 | 2019-04-13 02:12:36 | 215.48 | 31.82 | 6.24 | 2019-04-12 21:00:04 | 2019-04-13 03:24:35 | 216.87 | 33.64 | 4.96 | 2019-04-12 20:06:03 | 2019-04-13 03:33:35 | 223.34 | 33.64 | 4.83 | 2019-04-12 21:18:05 | 2019-04-12 03:42:35 | 219.04 | 33.64 | 4.43 | 2019-04-12 21:27:04 | 2019-04-12 03:51:35 | 217.78 | 33.46 | 3.74 | +-------------------+---------------------+--------+-------+-------+ The Probability refers to the 2D spatial probability of the GW skymap enclosed in a given tile. The size of the tiles are 4.2x4.2 deg2 for TRE and 1.8 x 1.8 deg2 for TCA. These observations cover 73% and 38% of the 90% GW probability skymap for TRE and TCA respectively. The typical 3 sigma limiting magnitude for a 2 minute exposure is 17 for TRE and 18 for TCA. Results of the on-going analysis  will be reported in a later GCNC. 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.