![]() The first method consists in fitting the observed Two methods are used to characterize the pairwise. To the line of sight, induced by pairwise group peculiar velocities isĮvaluated. The redshift space distortion of the correlationįunction ξ(σ,π) in the directions parallel and perpendicular Galaxies selected in three dimensions from the Updated Zwicky GalaxyĬatalog - (UZC). We calculate two-point correlation functions of galaxies and groups of We conclude that ram-pressure alone is insufficient to account for the rapid and widespread truncation of star-formation observed in cluster galaxies, or the morphological transformation of Sab's to S0's that is necessary to explain the Butcher-Oemler effect. Galaxies orbiting within poorer clusters, or inclined to the direction of motion through the intra-cluster medium will lose significantly less gas. The timescale for this to occur is a fraction of a crossing time $\sim 10^7$ years. A spiral galaxy passing through the core of a rich cluster such as Coma, will have its gaseous disk truncated to $\sim 4$ kpc, thus losing $\sim 80%$ of its diffuse gas mass. However, at small radii it is also important to consider the potential provided by the bulge component. We find that the analytic expectation of Gunn & Gott (1972) relating the gravitational restoring force provided by the disk to the ram pressure force, provides a good approximation to the radius that gas will be stripped from a galaxy. We use 3-dimensional SPH/N-BODY simulations to study ram pressure stripping of gas from spiral galaxies orbiting in clusters. Our understanding of these galaxies has grown impressively in the past decade, but fundamental puzzles remain that will keep the Local Group at the forefront of galaxy evolution studies for some time. ![]() To complement the discussion and to serve as a foundation for future work, I present an extensive set of basic observational data in tables that summarize much of what we know and still do not know about these nearby dwarfs. I then discuss the detailed properties of this sample, including (a) the integrated photometric parameters and optical structures of these galaxies, (b) the content, nature, and distribution of their interstellar medium (ISM), (c) their heavy-element abundances derived from both stars and nebulae, (d) the complex and varied star-formation histories of these dwarfs, (e) their internal kinematics, stressing the relevance of these galaxies to the "dark matter problem" and to alternative interpretations, and (f) evidence for past, ongoing, and future interactions of these dwarfs with other galaxies in the Local Group and beyond. ![]() In this review, I update the census of Local Group dwarfs based on the most recent distance and radial velocity determinations. Monthly Notices of the Royal Astronomical Society Oxford University Press The Local Group dwarf galaxies offer a unique window to the detailed properties of the most common type of galaxy in the Universe. Therefore, the observation of a galaxy's gas tail may be misleading about the galaxy's direction of motion. A major difference between different inclinations is the degree of asymmetry introduced in the remaining gas disc.We demonstrate that the tail of gas stripped from the galaxy does not necessarily point in a direction opposite to the galaxy's direction of motion. We show that in non-edge-on geometries the stripping proceeds remarkably similar. For very strong ram pressures, the disc will be stripped completely, and for very weak ram pressures, mass loss is negligible independent of inclination. We explain this behaviour by extending Gunn & Gott's estimate of the stripping radius, which is valid for face-on geometries, to moderate inclinations.The inclination plays a role as long as the ram pressure is comparable to pressures in the galactic plane, which can span two orders of magnitude. In this work we focus on a systematic study of the effect of the inclination angle between the direction of motion and the galaxy's rotation axis.In agreement with some previous works, we find that the inclination angle does not play a major role for the mass loss as long as the galaxy is not moving close to edge-on (inclination angle ≲60°). But only a small fraction of galaxies is moving face-on. Studies of galaxies that move face-on have predicted that in such a geometry the galaxy can lose a substantial amount of its interstellar medium. We present three-dimensional (3D) hydrodynamical simulations of ram pressure stripping of massive disc galaxies in clusters. Ram pressure stripping of disc galaxies: the role of the inclination angle Ram pressure stripping of disc galaxies: the role of the inclination angle
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