Unveiling the Nature of Giant Ellipticals and their Stellar Halos with the VST

Journal
Date Issued
2017
Author(s)
•
Capaccioli, M.
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•
•
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Limatola, L.
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Cooper, A. P.
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•
Forbes, D. A.
•
•
DOI
Abstract
Observations of diffuse starlight in the outskirts of galaxies provide fundamental constraints on the cosmological context of galaxy assembly in the Lambda Cold Dark Matter model, which predicts that galaxies grow through a combination of in-situ star formation and accretion of stars from other galaxies. Accreted stars are expected to dominate in the outer parts of galaxies. Since dynamical timescales are longer in these regions, substructures related to accretion, such as streams and shells, can persist over many Gyr. In this work we use extremely deep g- and i-band images of six massive early- type galaxies (ETGs) from the VEGAS survey to constrain the properties of their accreted stellar components. The wide field of view of OmegaCAM on the VLT Survey Telescope (VST) also allows us to investigate the properties of small stellar systems (such as globular clusters, ultra-compact dwarfs and satellite galaxies) in the halos of our galaxies. By fitting light profiles, and comparing the results to simulations of elliptical galaxy assembly, we have identified signatures of a transition between relaxed and unrelaxed accreted components and can constrain the balance between in-situ and accreted stars.
Volume
170
Start page
34
Uri
Url
Issn Identifier
0722-6691
Ads BibCode
2017Msngr.170...34S
Rights
open.access
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