| | |
| | |
Stat |
Members: 3643 Articles: 2'487'895 Articles rated: 2609
29 March 2024 |
|
| | | |
|
Article overview
| |
|
The accretion origin of the Milky Way's stellar halo | Eric F. Bell
; Daniel B. Zucker
; Vasily Belokurov
; Sanjib Sharma
; Kathryn V. Johnston
; James S. Bullock
; David W. Hogg
; Knud Jahnke
; Jelte T. A. de Jong
; Timothy C. Beers
; N. W. Evans
; Eva K. Grebel
; Zeljko Ivezic
; Sergey E. Koposov
; Hans-Walter Rix
; Donald P. Schneider
; Matthias Steinmetz
; Adi Zolotov
; | Date: |
31 May 2007 | Subject: | Astrophysics (astro-ph) | Abstract: | We have used data from the Sloan Digital Sky Survey (SDSS) Data Release 5 to
explore the overall structure and substructure of the stellar halo of the Milky
Way using about 4 million color-selected main sequence turn-off stars. We fit
oblate and triaxial broken power-law models to the data, and found a `best-fit’
oblateness of the stellar halo c/a ~ 0.6, and halo stellar masses between
Galactocentric radii of 1 and 40kpc of ~4x10^8 M_sun. The density profile of
the stellar halo is approximately r^{-3}; it is possible that the power law
slope is shallower inside 20kpc and steeper outside that radius. Yet, we found
that all smooth and symmetric models were very poor fits to the distribution of
stellar halo stars because the data exhibit a great deal of spatial
substructure. We quantified deviations from a smooth oblate/triaxial model
using the RMS of the data around the model profile on scales >~100pc, after
accounting for the (known) contribution of Poisson uncertainties. The
fractional RMS deviation of the actual stellar distribution from any smooth,
parameterized halo model is >~40%: hence, the stellar halo is highly
structured. We compared the observations with simulations of galactic stellar
halos formed entirely from the accretion of satellites in a cosmological
context by analysing the simulations in the same way as the data. While the
masses, overall profiles, and degree of substructure in the simulated stellar
halos show considerable scatter, the properties and degree of substructure in
the Milky Way’s halo match well the properties of a `typical’ stellar halo
built exclusively out of the debris from disrupted satellite galaxies. Our
results therefore point towards a picture in which an important fraction of the
Milky Way’s stellar halo has been accreted from satellite galaxies. | Source: | arXiv, arxiv.0706.0004 | Services: | Forum | Review | PDF | Favorites |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser claudebot
|
| |
|
|
|
| News, job offers and information for researchers and scientists:
| |