FM 047-02: a collisional pair of galaxies with a ring^⋆

¹ MCTI/Laboratório Nacional de Astrofísica, Rua Estados Unidos, 154, Bairro das Nações, CEP 37.504-364 Itajubá MG Brazil
e-mail: mfaundez@lna.br; mabans@lna.br
² UNIFEI, Instituto de Engenharia de Produção e Gestão, Av. BPS 1303 Pinheirinho, 37500-903 Itajubá, MG, Brazil
³ Universidade do Vale do Paraíba, UNIVAP. Av. Shishima Hifumi, 2911, Urbanova CEP: 12244-000, São José dos Campos, SP, Brazil
e-mail: angela.krabbe@gmail.com
⁴ UEFS, Departamento de Física, Av. Transnordestina, S/N, Novo Horizonte, CEP 44036-900 Feira de Santana, BA, Brazil
⁵ UEFS, Observatório Astronômico Antares, Rua da Barra, 925, Jardim Cruzeiro, CEP 44024-432 Feira de Santana, BA, Brazil
e-mail: paulopoppe@gmail.com; vmartin1963@gmail.com; irafbear@gmail.com

Received: 22 January 2013
Accepted: 17 July 2013

Abstract

Aims. We investigate the nature of the galaxy pair FM 047-02, which has been proposed as an archetype of the Solitaire types of peculiar (collisional) ring galaxies.

Methods. The study is based on long-slit spectrophotometric data in the range of 3500–9500 Å obtained with the Gemini Multi-Object Spectrograph at Gemini South (GMOS-S). The absorption spectra were used to determine the radial velocity. The stellar population synthesis code STARLIGHT was used to investigate the star formation history of the galaxy pair FM 047-02.

Results. During the whole long-slit signal, the spectra of both galaxies resemble those of an early-type galaxy. Both objects are dominated by an old stellar population of 2 × 10⁹ < t ≤ 13 × 10⁹ yr and a small, but a non-negligible fraction (about 13%) of young stars of t ≤ 5 × 10⁷ yr are estimated to contribute to the optical flux for NED02. Both observed small radial-velocity differences, and the structures around NED01 suggest an ongoing tidal interaction of both galaxies.

Conclusions. The spectroscopic results and the morphological peculiarities of NED01 can be adequately interpreted as continuing off-center stage of interaction with the companion galaxy NED02. The core of NED01 and NED02 are in counter-rotating motion. The visual appearance of NED01, its kinematical properties, the smooth distribution of material in the ring, and its off-centered nucleus, characterize it as a true archetype of a Solitaire-type ring galaxy in an advanced stage of ring formation.