[vsnet-grb-info 24281] LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL observations.

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26380
SUBJECT: LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL observations.
DATE:    19/12/07 18:32:58 GMT
FROM:    Aniello Grado at INAF-OAC  <aniello.grado at gmail.com>

AUTHORS: A. Grado (INAF-Napoli), E. Cappellaro (INAF-Padova), F. Getman
(INAF-Napoli), E. Brocato (INAF-Abruzzo), S. Covino (INAF-Brera),
L. Nicastro (INAF-OAS),  F. Onori (IAPS), S. Piranomonte (INAF-OARm)
on behalf of GRAWITA.

We observed the field of the gravitational wave event S191204r (GCN
circular #26334) in r' band with the VLT Survey Telescope (VST) equipped
with Omegacam (1 square degree FOV) (Proposal ID ESO 0104.D-0049).
We secured three epochs distributed in time as reported in the following
table where the last column contains the average FWHM in arcsec.

epoch 1 2019-12-05 from 01:18:13.867 to 02:52:28.862 1.05
epoch 2 2019-12-05 from 07:28:59.733 to 09:03:39.067 1.29
epoch 3 2019-12-06 from 01:46:07.055 to 03:28:14.961 0.7

all time are in UTC.

Individual epoch covers 20 square degrees enclosing ~ 60% of the
localization probability region.
Each one square degree pointing is the coaddition of three dithered
exposures for a total exposure time of 135 seconds.
Weather conditions were good in particular in the last epoch where the
FWHM reached a lower value < 0.5".

Automatic VST data processing was done with the VSTTube pipeline
(Grado et al. 2012 Mem.SAIt 19, 362).
Transient search is in progress.
We acknowledge excellent support from the ESO User Support Department
and from ESO observing staff in Paranal.