TITLE: GCN CIRCULAR NUMBER: 25669 SUBJECT: LIGO/Virgo S190814bv: GRAWITA VST-ESO PARANAL observations and independent transient candidates discovery. DATE: 19/09/05 19:31:31 GMT FROM: Aniello Grado at INAF-OAC AUTHORS: A. Grado (INAF-Napoli), E. Cappellaro (INAF-Padova), E. Brocato (INAF-Abruzzo), S. Covino (INAF-Brera), F. Getman (INAF-Napoli), G. Greco (University Urbino) , P. D'avanzo (INAF-Brera), A. Rossi (INAF-OAS), E. Palazzi (INAF-OAS), S. Yang (INAF-Padova) on behalf of GRAWITA. We observed the field of S190814bv (GCN 25324 and updated GCN 25333) in r' band with the VLT Survey Telescope (VST) equipped with Omegacam (1 sqdeg FOV) (Proposal ID ESO 0103.D-0070 ). The field was observed for a total of 5 epochs distributed as reported in the following table. epoch 1 2019-08-15 from 08:50:26.860 to 10:13:47.602 epoch 2 2019-08-16 from 05:29:37.904 to 07:20:36.231 epoch 3 2019-08-19 from 04:55:59.697 to 06:08:28.809 epoch 3 2019-09-20 from 03:45:54.370 to 04:39:27.598 epoch 4 2019-8-22 from 03:01:00.585 to 05:41:44.089 epoch 5 2019-08-29 from 09:07:41.251 to 09:36:29.055 epoch 5 2019-08-30 from 07:49:42.449 to 09:34:10.334 all time are in UTC. In the first night we imaged 18 sqdeg covering 65% of the localization probability region. Starting from the second epoch we modified the pointings to improve the updated skymap coverage. The area imaged is 23 sqdeg covering 87% of the localization region. Each 1 sqdeg pointing was observed three times for a total exposure time of 135 seconds. Images were analized using the our photometric pipelines (Brocato et al. 2018 MNRAS, 474,1). The final vetting was done via visual inspection. The candidates were matched against the Minor Planet Center to further filter against slow moving asteroids. The three most outstanding candidates, already reported in TNS, and visible in at least three epochs are: Name | TNS Name | RA | Dec | Night | Mag | MAGERR VST J004656.70-252236.7 | AT2019npd | 00:46:56.711 | -25:22:36.43 | 2019-08-21 | 19.874 +/- 0.062 VST J004847.88-251823.5 | AT2019noq | 00:48:47.882 | -25:18:23.46 | 2019-08-15 | 19.962 +/- 0.033 VST J005605.55-243826.4 | AT2019nve | 00:56:05.510 | -24:38:26.40 | 2019-08-14 | 20.531 +/- 0.083 VST J004659.45-230559.5 | AT2019nyv | 00:46:59.451 | -23:05:59.50 | 2019-8-15 | 21.200 +/- 0.087 where the magnitude and night refers to the peak value. Automatic VST data processing was done with the VSTTube pipeline (Grado et al. 2012 Mem.SAIt 19, 362). The pointing sequence was generated using the GWsky script ( https://github.com/ggreco77/GWsky). We acknowledge excellent support from the ESO User Support Department and from ESO observing staff in Paranal.