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What shapes stellar metallicity gradients of massive galaxies at large radii?

Published online by Cambridge University Press:  21 March 2017

Michaela Hirschmann
Michaela Hirschmann*
Affiliation:
UPMC-CNRS, UMR7095, Institut d’ Astrophysique de Paris, F-75014 Paris, France email: hirschma@iap.fr
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Abstract

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We investigate the differential impact of physical mechanisms, mergers and internal energetic phenomena, on the evolution of stellar metallicity gradients in massive, present-day galaxies employing sets of high-resolution, cosmological zoom simulations. We demonstrate that negative metallicity gradients at large radii (>2Reff) originate from the accretion of metal-poor stellar systems. At larger radii, galaxies become typically more dominated by stars accreted from satellite galaxies in major and minor mergers. However, only strong galactic, stellar-driven winds can sufficiently reduce the metallicity content of the accreted stars to realistically steepen the outer metallicity gradients in agreement with observations. In contrast, the gradients of the models without winds are inconsistent with observations. Moreover, we discuss the impact of additional AGN feedback. This analysis greatly highlights the importance of both energetic processes and merger events for stellar population properties of massive galaxies at large radii. Our results are expected to significantly contribute to the interpretation of current and up-coming IFU surveys (e.g. MaNGA, CALIFA).

Keywords

methods: numericalgalaxies: evolutiongalaxies: formationgalaxies: elliptical and lenticulargalaxies: stellar content
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 11 , Symposium S321: Formation and Evolution of Galaxy Outskirts , March 2016 , pp. 93 - 95
Copyright
Copyright © International Astronomical Union 2017 

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