Angular momentum evolution of galaxies in EAGLE

del P. Lagos, Claudia, Theuns, Tom, Stevens, Adam R. H., Cortese, Luca, Padilla, Nelson D., Davis, Timothy A. ORCID: https://orcid.org/0000-0003-4932-9379, Contreras, Sergio and Croton, Darren 2017. Angular momentum evolution of galaxies in EAGLE. Monthly Notices of the Royal Astronomical Society 464 (4) , pp. 3850-3870. 10.1093/mnras/stw2610

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Abstract

We use the EAGLE cosmological hydrodynamic simulation suite to study the specific angular momentum of galaxies, j, with the aims of (i) investigating the physical causes behind the wide range of j at fixed mass and (ii) examining whether simple, theoretical models can explain the seemingly complex and non-linear nature of the evolution of j. We find that j of the stars, jstars, and baryons, jbar, are strongly correlated with stellar and baryon mass, respectively, with the scatter being highly correlated with morphological proxies such as gas fraction, stellar concentration, (u-r) intrinsic colour, stellar age and the ratio of circular velocity to velocity dispersion.We compare with available observations at z = 0 and find excellent agreement. We find that jbar follows the theoretical expectation of an isothermal collapsing halo under conservation of specific angular momentumto within 50%, while the subsample of rotation-supported galaxies are equally well described by a simple model in which the disk angular momentum is just enough to maintain marginally stable disks. We extracted evolutionary tracks of the stellar spin parameter of EAGLE galaxies and found that the fate of their jstars at z = 0 depends sensitively on their star formation and merger histories. From these tracks, we identified two distinct physical channels behind low jstars galaxies at z = 0: (i) galaxy mergers, and (ii) early star formation quenching. The latter can produce galaxies with low jstars and early-type morphologies even in the absence of mergers.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Uncontrolled Keywords:	galaxies: evolution galaxies: formation galaxies: fundamental parameters galaxies: structure
Publisher:	Oxford University Press
ISSN:	0035-8711
Funders:	STFC
Date of First Compliant Deposit:	18 November 2016
Date of Acceptance:	10 October 2016
Last Modified:	22 Nov 2024 14:45
URI:	https://orca.cardiff.ac.uk/id/eprint/96260

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