TY  - JOUR
A1  - Hani, Maan H.
A1  - Ellison, Sara L.
A1  - Sparre, Martin
A1  - Grand, Robert J. J.
A1  - Pakmor, Rüdiger
A1  - Gómez, Facundo A.
A1  - Springel, Volker
T1  - The diversity of the circumgalactic medium around z=0 Milky Way-mass galaxies from the Auriga simulations
T2  - Monthly notices of the Royal Astronomical Society
N2  - 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 MilkyWay-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-star galaxies is extremely diverse: column densities of commonly observed species span similar to 3-4 dex and their covering fractions range from similar to 5 to 90 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-star 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.
KW  - methods: numerical
KW  - galaxies: evolution
KW  - galaxies: haloes
Y1  - 2019
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/48273
SN  - 0035-8711
SN  - 1365-2966
VL  - 488
IS  - 1
SP  - 135
EP  - 152
PB  - Oxford Univ. Press
CY  - Oxford
ER  -