Constraints on Radial Migration in Spiral Galaxies - II. Angular momentum distribution and preferential migration

Abstract

The orbital angular momentum of individual stars in galactic discs can be permanently changed through torques from transient spiral patterns. Interactions at the corotation resonance dominate these changes and have the further property of conserving orbital circularity. We derived in an earlier paper an analytic criterion that an unperturbed stellar orbit must satisfy in order for such an interaction to occur i.e. for it to be in a trapped orbit around corotation. We here use this criterion in an investigation of how the efficiency of induced radial migration for a population of disc stars varies with the angular momentum distribution of that population. We frame our results in terms of the velocity dispersion of the population, this being an easier observable than is the angular momentum distribution. Specifically, we investigate how the fraction of stars in trapped orbits at corotation varies with the velocity dispersion of the population, for a system with an assumed flat rotation curve. Our analytic results agree with the finding from simulations that radial migration is less effective in populations with 'hotter' kinematics. We further quantify the dependence of this trapped fraction on the strength of the spiral pattern, finding a higher trapped fraction for higher amplitude perturbations.

28 pages, 15 figure, accepted for publication in MNRAS

References in corpus (8)

• galpy: A Python Library for Galactic Dynamics
• Riding the Spiral Waves: Implications of Stellar Migration for the Properties of Galactic Disks
• Transient spirals as superposed instabilities
• The effect of radial migration on galactic disks
• The Blueshifting and Baldwin effects for the [OIII] 5007 Emission Line in Type 1 Active Galactic Nuclei
• The Rich Are Different: Evidence from the RAVE Survey for Stellar Radial Migration
• Constraints on Radial Migration in Spiral Galaxies I. Analytic Criterion for Capture at Corotation
• Forming disc galaxies in major mergers: III. The effect of angular momentum on the radial density profiles of disc galaxies

Cited by in corpus (6)

• Local Simulations of Spiral Galaxies with the TIGRESS Framework: I. Star Formation and Arm Spurs/Feathers
• Yule-Simpson's paradox in Galactic Archaeology
• Instabilities in disc galaxies: from noise to grooves to spirals
• Radial migration and vertical action in N-body simulations
• How the bar properties affect the induced spiral structure
• Power-law Sersic profiles in hydrostatic stellar galaxy discs