Three-dimensional simulations of the interstellar medium in dwarf galaxies - I. Ram pressure stripping

Abstract

We present three‐dimensional hydrodynamic simulations of ram pressure stripping in dwarf galaxies. Analogous studies on this subject usually deal with much higher ram pressures, typical of galaxy clusters, or mild ram pressure due to the gas halo of the massive galactic companions. We extend over previous investigations by considering flattened, rotating dwarf galaxies subject to ram pressures typical of poor galaxy groups. We study the ram pressure effects as a function of several parameters such as galactic mass and velocity, ambient gas density and the angle between the galactic plane and the direction of motion. It turns out that this last parameter plays a role only when the gas pressure in the galactic centre is comparable to the ram pressure. Despite the low values of the ram pressure, some dwarf galaxies can be completely stripped after 1–2 Myr. This poses an interesting question on the aspect of the descents and, more in general, on the morphological evolution of dwarf galaxies. In cases in which the gas is not completely stripped, the propagation of possible galactic wind may be influenced by the disturbed distribution of the interstellar matter. We also consider the modification of the interstellar matter surface density induced by the ram pressure and find that the resulting compression may trigger star formation over long time‐spans.

3D global simulations of a cosmic-ray-driven dynamo in dwarf galaxies

“…This type of galaxy has no bulge (Governato et al 2010), which is present in more massive disk galaxies. In our model the stars are distributed in an infinitesimally thin Kuzmin disk following previous numerical works on dwarf galaxies (Marcolini et al 2003(Marcolini et al , 2004. For the DM halo we used the purely phenomenological profile proposed by Burkert (1995).…”

“…To find the global gas distribution we used the potential method described in Wang et al (2010). The detailed parameters of the gravitational potentials are shown in Table 1 and its values were mostly taken from Marcolini et al (2003) with only slight modifications. From the gas distribution the CR component distribution was found, assuming that they are in pressure equilibrium.…”

Nature vs. nurture in the low-density environment: structure and evolution of early-type dwarf galaxies in poor groups

“…Low-mass galaxies are more susceptible to environmental effects owing to their shallow potential well that facilitates the removal of gas from the galaxies. Hydrodynamical simulations show that, while for massive galaxies ram-pressure stripping is only effective in the cores of rich clusters, dwarf galaxies can be completely stripped of their gas even in poor groups (e.g., Bekki et al 2001;Bekki et al 2002;Marcolini et al 2003). Suffocation, ram-pressure stripping, and galaxy harassment can deprive dwarf galaxies of their gas reservoir, quenching star formation and transforming them into passive dwarf ellipticals.…”

Metal Enrichment Processes

“…As ram-pressure stripping is such a common process, there are many simulations in which the stripping process of galaxies was calculated for different types of galaxies: spirals, ellipticals and dwarfs (Abadi et al 1999;Quilis et al 2000;Mori & Burkert 2000;Toniazzo & Schindler 2001;Schulz & Struck 2001;Vollmer et al 2001;Hidaka & Sofue 2002;Bekki & Couch 2003;Otmianowska-Mazur & Vollmer 2003;Acreman et al 2003;Marcolini et al 2003;Roediger & Hensler 2005;Mayer et al 2006;Vollmer et al 2006, see Fig. 2).…”