NGC 4254: a spiral galaxy entering the Virgo cluster

Abstract

Abstract. Deep Effelsberg H spectra of the one-armed, bright Virgo cluster spiral galaxy NGC 4254 are presented. Five different positions were observed in the 21 cm H line with the Effelsberg 100-m telescope: one in the center and 4 located one HPBW to the NE, NW, SW, and SE, respectively, from the galaxy center. The spectra are compared to existing deep VLA observations, and the single dish and interferometric H data are used to constrain a dynamical model which includes the effects of ram pressure. The peculiar, one-armed spiral pattern of NGC 4254 and its distorted and kinematically perturbed atomic gas distribution can be explained by a close and rapid encounter ∼280 Myr ago with another massive Virgo galaxy, followed by ram pressure stripping that is ongoing. The stripping occurs almost face-on, since the angle between the disk and the orbital plane is 70 • . The galaxy with which NGC 4254 had its encounter is tentatively identified as the lenticular NGC 4262.

Asymmetric mass models of disk galaxies

“…3.2). Gas accretion on the Hi disk outskirts after a tidal interaction with a companion, as suggested by numerical simulations of Vollmer et al (2005) and Duc & Bournaud (2008), is likely to generate a disk warping. If it exists, this Hi warp cannot be bisymmetric because of the more prominent m = 1 pattern.…”

“…Phookun et al (1993) proposed a scenario where the Hi arm is triggered by gas infalling and winding on the disk, resulting from a tidal encounter. Based on numerical simulations, Vollmer et al (2005) mimic the asymmetric disk and perturbed Hi kinematics by a flyby of a massive companion, coupled with ram pressure stripping from the Virgo intracluster medium (ICM). These authors argued that M 99 is entering the Virgo cluster for the first time.…”

“…A tidal interaction between M 99 and a massive companion has actually occurred in the past Gyr, maybe 750 Myr ago (Duc & Bournaud 2008). The interaction with the gravitational field of the Virgo cluster is likely very active too, as M 99 has entered the cluster (Vollmer et al 2005). If triggered by such tidal processes, the DM core shift seems to be a long-lived dynamical event in M 99.…”

Spectacular tails of ionized gas in the Virgo cluster galaxy NGC 4569

“…The Virgo cluster has another major quality: owing to its proximity, the angular resolution of multifrequency data is comparable to that obtained in high-resolution simulations. The comparison of the kinematic and spectrophotometric properties of several bright Virgo galaxies has indeed been crucial for the identification of the perturbing process (Vollmer et al 1999(Vollmer et al , 2000(Vollmer et al , 2005(Vollmer et al , 2006(Vollmer et al , 2008a(Vollmer et al , 2008b(Vollmer et al , 2012Vollmer 2003;Kenney et al 2004;Boselli et al 2005Abramson et al 2011;Kenney et al 2014;Abramson & Kenney 2014;Cortes et al 2015).…”

Stripped gas as fuel for newly formed H ii regions in the encounter between VCC 1249 and M 49: a unified picture from NGVS and GUViCS

“…Perhaps the most spectacular example of an interacting system in the Virgo cluster is that between NGC 4438 and M 86, whose morphology and gas content require that tidal interaction and ram-pressure stripping are simultaneously occuring (Kenney et al 2008). Similarly, the perturbations observed in NGC 4654 and NGC 4254 can be modeled with a close encounter with a nearby companion combined with ram-pressure stripping (Vollmer 2003;Vollmer et al 2005).…”