Published in

Oxford University Press (OUP), Monthly Notices of the Royal Astronomical Society, 1(488), p. 135-152, 2019

DOI: 10.1093/mnras/stz1708

Links

Tools

Export citation

Search in Google Scholar

The diversity of the circumgalactic medium around z = 0 Milky Way-mass galaxies from the Auriga simulations

This paper was not found in any repository, but could be made available legally by the author.
This paper was not found in any repository, but could be made available legally by the author.

Full text: Unavailable

Green circle
Preprint: archiving allowed
Green circle
Postprint: archiving allowed
Green circle
Published version: archiving allowed
Data provided by SHERPA/RoMEO

Abstract

ABSTRACT Galaxies are surrounded by massive gas reservoirs (i.e. the circumgalactic medium; CGM) which play a key role in their evolution. The properties of the CGM, which are dependent on a variety of internal and environmental factors, are often inferred from absorption line surveys which rely on a limited number of single lines-of-sight. In this work we present an analysis of 28 galaxy haloes selected from the Auriga project, a cosmological magneto-hydrodynamical zoom-in simulation suite of isolated Milky Way-mass galaxies, to understand the impact of CGM diversity on observational studies. Although the Auriga haloes are selected to populate a narrow range in halo mass, our work demonstrates that the CGM of L⋆ galaxies is extremely diverse: column densities of commonly observed species span ∼3 − 4 dex and their covering fractions range from ${∼ } 5$ to $90{{\ \rm per\ cent}}$. Despite this diversity, we identify the following correlations: 1) the covering fractions (CF) of hydrogen and metals of the Auriga haloes positively correlate with stellar mass, 2) the CF of H i, C iv, and Si ii anticorrelate with active galactic nucleus luminosity due to ionization effects, and 3) the CF of H i, C iv, and Si ii positively correlate with galaxy disc fraction due to outflows populating the CGM with cool and dense gas. The Auriga sample demonstrates striking diversity within the CGM of L⋆ galaxies, which poses a challenge for observations reconstructing CGM characteristics from limited samples, and also indicates that long-term merger assembly history and recent star formation are not the dominant sculptors of the CGM.

Beta version