Rotation curve bifurcations as indicators of close recent galaxy encounters

S. PEDROSA; P. B. TISSERA; I. FUENTES-CARRERA; C. MENDES DE OLIVEIRA

ASTRONOMY AND ASTROPHYSICS

EDP Science

Lugar: París, Francia; Año: 2008 vol. 484 p. 299 - 302

0004-6361

Context. Rotation curves of interacting galaxies often show that velocities are either rising or falling in the direction of the companion galaxy.Aims. We seek to reproduce and analyse these features in the rotation curves of simulated equal-mass galaxies suffering a one-to-one encounter as possible indicators of close encounters.Methods. Using simulations of major mergers in 3D, we study the time evolution of these asymmetries in a pair of galaxies duringthe first passage.Results. Our main results are: (a) the rotation curve asymmetries appear right at pericentre of the first passage, (b) the significantdisturbed rotation velocities occur within a small time interval, of ∼0.5 Gyr h−1 , and, therefore, the presence of bifurcation in thevelocity curve could be used as an indicator of the pericentre occurrence. These results are in qualitative agreement with previous findings for minor mergers and flybys.