TOROS Optical follow-up of the Advanced LIGO-VIRGO O2 second observational campaign
astro-ph.HE
/ Authors
Rodolfo Artola, Martin Beroiz, Juan Cabral, Richard Camuccio, Moises Castillo, Vahram Chavushyan, Carlos Colazo, Hector Cuevas Larenas, Darren L. DePoy, Mario C. Díaz
and 41 more authors
Mariano Domínguez, Deborah Dultzin, Daniela Fernández, Antonio C. Ferreyra, Aldo Fonrouge, José Franco, Darío Graña, Carla Girardini, Sebastián Gurovich, Antonio Kanaan, Diego G. Lambas, Marcelo Lares, Alejandro F. Hinojosa, Andrea Hinojosa, Americo F. Hinojosa, Omar López-Cruz, Lucas M. Macri, Jennifer L. Marshall, Raul Melia, Wendy Mendoza, José L. Nilo Castellón, Nelson Padilla
/ Abstract
We present the results of the optical follow-up, conducted by the TOROS collaboration, of gravitational wave events detected during the Advanced LIGO-Virgo second observing run (Nov 2016 -- Aug 2017). Given the limited field of view ($\sim100\arcmin$) of our observational instrumentation we targeted galaxies within the area of high localization probability that were observable from our sites. We analyzed the observations using difference imaging, followed by a Random Forest algorithm to discriminate between real and bogus transients. For all three events that we respond to, except GW170817, we did not find any bona fide optical transient that was plausibly linked with the observed gravitational wave event. Our observations were conducted using telescopes at Estación Astrofísica de Bosque Alegre, Cerro Tololo Inter-American Observatory, and the Dr. Cristina V. Torres Memorial Astronomical Observatory. Our results are consistent with the LIGO-Virgo detections of a binary black hole merger (GW170104) for which no electromagnetic counterparts were expected, as well as a binary neutron star merger (GW170817) for which an optical transient was found as expected.