Home News About Us Contact Contributors Disclaimer Privacy Policy Help FAQ

Home
Search
Quick Search
Advanced
Fulltext
Browse
Collections
Persons
My eDoc
Session History
Login
Name:
Password:
Documentation
Help
Support Wiki
Direct access to
document ID:


          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents



ID: 731705.0, MPI für Astronomie / Publikationen_mpia
The information content of stellar halos: Stellar population gradients and accretion histories in early-type illustris galaxies
Authors:Cook, B. A.; Conroy, C.; Pillepich, A.; Rodriguez-Gomez, V.; Hernquist, L.
Date of Publication (YYYY-MM-DD):2016
Title of Journal:The Astrophysical Journal
Volume:833
Issue / Number:2
Start Page:id. 158 (15 pp)
Audience:Not Specified
Abstract / Description:Long dynamical timescales in the outskirts of galaxies preserve the information content of their accretion histories, for example in the form of stellar population gradients. We present a detailed analysis of the stellar halo properties of a statistically representative sample of early-type galaxies from the Illustris simulation, and show that stellar population gradients at large radii can indeed be used to infer basic properties of galactic accretion histories. We measure metallicity, age, and surface-brightness profiles in quiescent Illustris galaxies ranging from {M}\star = 1010-2 × 1012 {M} and show that they are in reasonable agreement with observations. At fixed mass, galaxies that accreted little of their stellar halo material tend to have steeper metallicity and surface-brightness profiles, between 2-4 effective radii ({R}e), than those with larger accreted fractions. Profiles of metallicity and surface-brightness in the stellar halo typically flatten from z = 1 to the present. This suggests that the accretion of stars into the stellar halo tends to flatten metallicity and surface-brightness profiles, a picture which is supported by the tight correlation between the two gradients in the stellar halo. We find no statistical evidence of additional information content related to accretion histories in stellar halo metallicity profiles, beyond what is contained in surface-brightness profiles. Age gradients in the stellar halo do not appear to be sensitive to galactic accretion histories, and none of the stellar population gradients studied are strongly correlated with the mean merger mass-ratio. Our findings relate specifically to regions of the stellar halo within 4 {R}e, but suggest that future observations that reach large radii outside galaxies (including to 10 {R}e and beyond) will have the best potential to constrain galactic accretion histories.
Free Keywords:galaxies: elliptical and lenticular; CD; galaxies: evolution; galaxies: halos; galaxies: stellar content
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0004-637X %R 10.3847/1538-4357/833/2/158
URL:http://adsabs.harvard.edu/abs/2016ApJ...833..158C
The scope and number of records on eDoc is subject to the collection policies defined by each institute - see "info" button in the collection browse view.