Exponential galaxy discs as the quasi-stationary distribution in a Markov chain model simulating stellar scattering

Abstract

Previous models have shown that stochastic scattering of stars in a two-dimensional galaxy disc can generate a time-independent surface density distribution that is an exponential divided by radius when a constant inward scattering bias is present. Here we show, using a Markov chain model, that similar profiles result from an outward scattering bias, although the disc surface density decreases slowly with time because of a net stellar outflow. The trend towards a near-exponential surface profile is robust, as it exists even if the scattering intensity has moderate radial and time dependences, subject to some limitations on the scattering rates discussed in the text. The exponential scale length of the pseudo-equilibrium disc depends on the scattering bias, the scattering length, and the size of the disc where scattering is important.

18 pages, 20 figures

References in corpus (11)

• Rapid formation of exponential disks and bulges at high redshift from the dynamical evolution of clump cluster and chain galaxies
• Color Profiles of Spiral Galaxies: Clues on Outer-Disk Formation Scenarios
• The effect of radial migration on galactic disks
• On the formation of extended galactic disks by tidally disrupted dwarf galaxies
• Constraints on Radial Migration in Spiral Galaxies - II. Angular momentum distribution and preferential migration
• The Origin of Exponential Star-forming Disks
• Shrinking Galaxy Disks with Fountain-Driven Accretion from the Halo
• Exponential Disks from Stellar Scattering: III. Stochastic Models
• Power-law Sersic profiles in hydrostatic stellar galaxy discs
• Entropy and Mass Distribution in Disc Galaxies
• Orbits and action changes during star-clump encounters responsible for the origin of exponential discs in dwarf galaxies