Mon. Not. R. Astron. Soc., 480, 3257-3278 (2018/November-1)
Kinematics and physical properties of the nearby galaxy NGC 4656 and its TDG candidate.
MUNOZ-ELGUETA N., TORRES-FLORES S., AMRAM P., HERNANDEZ-JIMENEZ J.A., URRUTIA-VISCARRA F., MENDES DE OLIVEIRA C. and GOMEZ-LOPEZ J.A.
Abstract (from CDS):
Interacting galaxies provide us with an excellent laboratory for studying a number of physical phenomena associated with these processes. In this paper, we present a spectroscopic and kinematic analysis of the interacting galaxy NGC 4656 and its companion tidal dwarf galaxy (TDG) candidate, NGC 4656UV. Using Fabry-Perot and GMOS multislit data, we investigated the possible origin of NGC 4656UV. We found that NGC 4656UV has a low metallicity (12 + log(O/H)∼8.2) and it follows the mass-metallicity relation for normal dwarf galaxies. For NGC 4656, we estimated a flat oxygen abundance gradient of β= -0.027 ±0.029 dex kpc–1, which suggests the presence of gas flows induced by gravitational interactions. By analysing radial velocity profiles and by fitting a kinematic model of the observed velocity field, we confirm the literature result that NGC 4656 consists of one single body instead of two objects. We estimated a dynamical mass of 6.81.8–0.6×109 M☉ and R of 12.1 kpc from the kinematic model of NGC 4656. Although the observed velocity field is dominated by rotation at large scales (Vmax/σ >=2.8), important non-rotational motions are present at small scales. Based on these new results, and on previously published information, we propose that NGC 4656 and 4656UV are a pair of interacting galaxies. NGC 4656UV is a companion of NGC 4656 and it does not have a tidal origin. The interaction between the two could have triggered the star formation in NGC 4656UV and increased the star formation in the north-east side of NGC 4656.
© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
galaxies: dwarf - galaxies: individual: (NGC 4656) - galaxies: interactions - galaxies: kinematics and dynamics
Table 3: [MTA2018] NN (Nos 1-60).
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