Elliptical galaxies/stellar halos connection

Abstract

Cosmological simulations predict that early-type galaxies (ETGs) are the results of extended mass accretion histories. The latter are characterized by different numbers of mergers, mergers mass ratios and gas fractions, and timing. Depending on the sequence and nature of these mergers that follow the first phase of the in-situ star formation, these accretion histories may lead to ETGs that have low or high mass halos, and that rotate fast or slow. Since the stellar halos maintain the fossil records of the events that led to their formation, a discontinuity may be in place between the inner regions of ETGs and their outer halos, because the time required for the halos stars to exchange their energies and momenta is very long compared with the age of these systems. Exquisite deep photometry and extended spectroscopy for significant samples of ETGs are then used to quantify the occurrence and significance of such a transition in the galaxies structural and kinematical parameters. Once this transition radius is measured, its dependency with the effective radius of the galaxies light distribution and total stellar masses can be investigated. Such correlations can then be compared with the predictions of accreted, i.e. ex-situ vs. in-situ components from cosmological simulations to validate such models.

7 pages, 3 figures, Conference Proc. IAU Symp. 353, M. Valluri and J.A. Sellwood eds

References in corpus (21)

• The Atlas3D project -- I. A volume-limited sample of 260 nearby early-type galaxies: science goals and selection criteria
• Tracing Galaxy Formation with Stellar Halos I: Methods
• Structure and Formation of Elliptical and Spheroidal Galaxies
• The Growth of Massive Galaxies Since z=2
• The Two Phases of Galaxy Formation
• The SAURON project -- IX. A kinematic classification for early-type galaxies
• The Atlas3D project - XX. Mass-size and mass-sigma distributions of early-type galaxies: bulge fraction drives kinematics, mass-to-light ratio, molecular gas fraction and stellar initial mass function
• The stellar mass assembly of galaxies in the Illustris simulation: growth by mergers and the spatial distribution of accreted stars
• The ATLAS3D project - II. Morphologies, kinemetric features and alignment between photometric and kinematic axes of early-type galaxies
• How do minor mergers promote inside-out growth of ellipticals, transforming the size, density profile and dark matter fraction?
• HST and Spitzer imaging of red and blue galaxies at z~2.5: A correlation between size and star formation activity from compact quiescent galaxies to extended star forming galaxies
• Kinematic properties of early-type galaxy haloes using planetary nebulae
• Galactic accretion and the outer structure of galaxies in the CDM model
• Contributions to the accreted stellar halo: an atlas of stellar deposition
• SDSS-IV MaNGA: Stellar angular momentum of about 2300 galaxies: unveiling the bimodality of massive galaxy properties
• Intracluster Planetary Nebulae in Virgo: Photometric selection, spectroscopic validation and cluster depth
• The PN.S Elliptical Galaxy Survey: Data Reduction, Planetary Nebula Catalog, and Basic Dynamics for NGC 3379
• The Outer Stellar Halos of Galaxies: how Radial Merger Mass Deposition, Shells and Streams depend on Infall-Orbit Configurations
• The mass and angular momentum distribution of simulated massive early-type galaxies to large radii
• The SAMI Galaxy Survey: the intrinsic shape of kinematically selected galaxies
• Stellar orbits in cosmological galaxy simulations: the connection to formation history and line-of-sight kinematics

Cited by in corpus (1)

• The role of mergers and interactions in driving the evolution of dwarf galaxies over cosmic time