Pattern speed evolution and bar reformation

TL;DR

This paper investigates how bar pattern speeds in spiral galaxies evolve and reform through multiple episodes influenced by gas inflow, mass concentration, and galaxy morphology, using numerical simulations.

Contribution

It introduces numerical simulations that correlate bar pattern speed evolution with galaxy morphological changes and gas accretion effects.

Findings

Successive bars have different pattern speeds due to mass and velocity dispersion changes.

Galaxy morphology evolves alongside bar pattern speed variations.

Gas accretion can trigger multiple bar episodes in galaxy evolution.

Abstract

Bars in spiral galaxies can weaken through gas inflow towards the center, and angular momentum transfer. Several bar episodes can follow one another in the life of the galaxy, if sufficient gas is accreted from the intergalactic medium to revive young disks. Pattern speeds of the successive bars are different, due to mass concentration, or increased velocity dispersion of the remaining stellar component. In the same time, the spiral galaxy evolves in morphological type. Numerical simulations are presented, trying to correlate type and bar pattern speeds.