Observations of the First Electromagnetic Counterpart to a Gravitational-wave Source by the TOROS Collaboration

DÍAZ, M.C.; OLIVEIRA, C. MENDES DE; SÁNCHEZ, B.; AKRAS, S.; BEROIZ, M.; CAMUCCIO, R.; COELHO, P.; LARENAS, H. CUEVAS; DULTZIN, D.; GIRARDINI, C.; GUROVICH, S.; LARES, M.; MARSHALL, J.L.; PADILLA, N.; QUIÑONES, C.; RIGUCCINI, L.; SAMPEDRO, L.; STARCK, M.; ZADROZNY, A.; LAMBAS, D. GARCIA; RIBEIRO, T.; ABRAMO, L.R.; ARTOLA, R.; CABRAL, J.; CHAVUSHYAN, V.; COSTA-DUARTE, M.V.; ROMERO, M. DOMÍNGUEZ; GARCÍA, J.; GONÇALVES, T.S.; KANAAN, A.; LÓPEZ-CRUZ, O.; MOLINO, A.; PLACCO, V.M.; RENZI, V.; RODRIGUEZ, H.; SODRÉ, L.; TORNATORE, M.; LAMBAS, D. GARCIA; RIBEIRO, T.; ABRAMO, L.R.; ARTOLA, R.; CABRAL, J.; CHAVUSHYAN, V.; COSTA-DUARTE, M.V.; ROMERO, M. DOMÍNGUEZ; GARCÍA, J.; GONÇALVES, T.S.; KANAAN, A.; LÓPEZ-CRUZ, O.; MOLINO, A.; PLACCO, V.M.; RENZI, V.; RODRIGUEZ, H.; SODRÉ, L.; TORNATORE, M.; MACRI, L.M.; CASTELLÓN, J. L. NILO; SCHOENELL, W.; ALCANIZ, J.S.; BONOLI, S.; CASTILLO, M.; COLAZO, C.; DEPOY, D.L.; FERNÁNDEZ, D.; GONÇALVES, D.R.; JIMÉNEZ-TEJA, Y.; LOPES DE OLIVEIRA, R.; MELIA, R.; PEÑUELA, T.; RIVERA, A. RAMÍ

Astrophysical Journal Letters

Institute of Physics Publishing

Lugar: Chicago; Año: 2017 vol. 848 p. 1 - 5

2041-8205

We present the results of prompt optical follow-up of the electromagnetic counterpart of the gravitational-wave event GW170817 by the Transient Optical Robotic Observatory of the South Collaboration. We detected highly significant dimming in the light curves of the counterpart (Δg = 0.17 ± 0.03 mag, Δr = 0.14 ± 0.02 mag, Δi = 0.10 ± 0.03 mag) over the course of only 80 minutes of observations obtained ∼35 hr after the trigger with the T80-South telescope. A second epoch of observations, obtained ∼59 hr after the event with the EABA 1.5 m telescope, confirms the fast fading nature of the transient. The observed colors of the counterpart suggest that this event was a "blue kilonova" relatively free of lanthanides.