A Virgo high-resolution Halpha kinematical survey: I. NGC 4438

L. Chemin (1, 2) , V. Cayatte (3) , C. Balkowski (2) , P. Amram (4) , C. Carignan (1) , A. Boselli (4) , C. Adami (4) , M. Marcelin (4) , O. Garrido (2) , O. Hernandez (1) , J. Boulesteix (4)

1 Département de Physique [Montréal]
2 GEPI - Galaxies, Etoiles, Physique, Instrumentation
3 LUTH (UMR_8102) - Laboratoire Univers et Théories
4 LAM - Laboratoire d'Astrophysique de Marseille

New Halpha emission-line observations of the Virgo cluster galaxy NGC 4438 are presented. Fabry-Perot interferometry data at an effective angular resolution of ~2\" are used to map the kinematics of the ionized gas in the galaxy. For the first time we obtain a velocity field covering a large area in NGC 4438, much larger than that deduced from previous HI and CO maps. The kinematics of the extended, low surface brightness Halpha filaments to the West of the galactic disk is discussed. We report on the discovery of a northern Halpha structure which is clumpier than the other filaments. Evidence for multiple spectral components through the data-cube are presented in a nuclear shell and in the approaching half of the disk. The role of VCC 1040, a dwarf elliptical galaxy located to the South of NGC 4438, is presented to investigate the origin of a small-scale stellar tail of NGC 4438. It could be due to a minor tidal interaction between the two galaxies.

Mots clés: galaxies: clusters: individual: NGC 4438; galaxies: interactions; galaxies: kinematics and dynamics

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]

L. Chemin, V. Cayatte, C. Balkowski, P. Amram, C. Carignan, et al.. A Virgo high-resolution Halpha kinematical survey: I. NGC 4438. Astronomy and Astrophysics - A&A, 2005, 436, pp.469-478. ⟨10.1051/0004-6361:20041664⟩. ⟨hal-00013772⟩