Angular momentum evolution for galaxies in a Lambda-CDM scenario

TL;DR

This study uses cosmological hydrodynamical simulations to analyze how galaxy components like discs and bulges evolve in angular momentum within a Lambda-CDM universe, comparing results with observations.

Contribution

It provides a detailed analysis of angular momentum distribution in galaxy components across different masses and redshifts using advanced simulations.

Findings

Simulated galaxies show correlations between angular momentum and mass similar to observations.

Discs and spheroids follow similar slopes in angular momentum-mass relations, with spheroids offset by a fixed fraction.

Simulations reproduce observed trends in galaxy size and angular momentum content.

Abstract

Galaxy formation in the current cosmological paradigm is a very complex process in which inflows, outflows, interactions and mergers are common events. These processes can redistribute the angular momentum content of baryons. Recent observational results suggest that disc formed conserving angular momentum while elliptical galaxies, albeit losing angular momentum, determine a correlation between the specific angular momentum of the galaxy and the stellar mass. These observations provide stringent constraints for galaxy formation models in a hierarchical clustering scenario. We aim to analyse the specific angular momentum content of the disc and bulge components as a function of virial mass, stellar mass and redshift. We also estimate the size of the simulated galaxies and confront them with observations. We use cosmological hydrodynamical simulations that include an effective, physically-motivated Supernova feedback which is able to regulate the star formation in haloes of different masses. We analyse the morphology and formation history of a sample of galaxies in a cosmological simulation by performing a bulge-disc decomposition of the analysed systems and their progenitors. We estimate the angular momentum content of the stellar and gaseous discs, stellar bulges and total baryons. In agreement with recent observational findings, our simulated galaxies have disc and spheroid components whose specific angular momentum contents determine correlations with the stellar and dark matter masses with the same slope, although the spheroidal components are off-set by a fixed fraction. Abridged.