Moderate Influence of Halo Spin on Stellar Mass Distributions in Dwarf and Massive Galaxies

TL;DR

This study investigates how halo spin influences stellar mass distribution in galaxies, finding an inverse correlation that impacts galaxy evolution and star formation, with high-spin halos leading to more extended stellar distributions.

Contribution

It introduces a semi-analytic method to estimate halo spins and demonstrates their significant role in shaping stellar surface densities across galaxy masses.

Findings

Inverse correlation between halo spin and stellar surface density.

High-spin halos retain angular momentum, suppressing central star formation.

High-spin halos lead to more extended stellar distributions.

Abstract

We estimate halo spins for HI-rich galaxies in the Arecibo Legacy Fast Alfa Survey using a semi-analytic approach, examining the relationship between halo spin and stellar surface density. Our findings reveal an inverse correlation in both low- and high-mass galaxy samples, with stellar surface density decreasing as halo spin increases. This trend highlights the pivotal role of halo spin in galaxy evolution and suggests a universal formation scenario: high-spin halos, accompanied by high-spin accreted gas, retain angular momentum, preventing gas from efficiently condensing in the galactic center and thus suppressing star formation. Consequently, weak feedback redistributes gas to the halo outskirts without significant expulsion. The shallower central gravitational potential in high-spin halos promotes outward stellar migration, leading to more extended stellar distributions and lower stellar surface densities.