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The hunt for the Milky Way's accreted disc

Ruchti, Gregory LU ; Read, Justin I.; Feltzing, Sofia LU ; Pipino, Antonio and Bensby, Thomas LU (2014) In Monthly Notices of the Royal Astronomical Society 444(1). p.515-526
Abstract
The Milky Way is expected to host an accreted disc of stars and dark matter. This forms as massive greater than or similar to 1 : 10 mergers are preferentially dragged towards the disc plane by dynamical friction and then tidally shredded. The accreted disc likely contributes only a tiny fraction of the MilkyWay's thin and thick stellar disc. However, it is interesting because (i) its associated 'dark disc' has important implications for experiments hoping to detect a dark matter particle in the laboratory; and (ii) the presence or absence of such a disc constrains the merger history of our Galaxy. In this work, we develop a chemodynamical template to hunt for the accreted disc. We apply our template to the high-resolution spectroscopic... (More)
The Milky Way is expected to host an accreted disc of stars and dark matter. This forms as massive greater than or similar to 1 : 10 mergers are preferentially dragged towards the disc plane by dynamical friction and then tidally shredded. The accreted disc likely contributes only a tiny fraction of the MilkyWay's thin and thick stellar disc. However, it is interesting because (i) its associated 'dark disc' has important implications for experiments hoping to detect a dark matter particle in the laboratory; and (ii) the presence or absence of such a disc constrains the merger history of our Galaxy. In this work, we develop a chemodynamical template to hunt for the accreted disc. We apply our template to the high-resolution spectroscopic sample from Ruchti et al., finding at present no evidence for accreted disc stars. Our results are consistent with a quiescent Milky Way with no greater than or similar to 1 : 10 mergers since the disc formed and a correspondingly light ` dark disc'. However, we caution that while our method can robustly identify accreted stars, our incomplete stellar sample makes it more challenging to definitively rule them out. Larger unbiased stellar samples will be required for this. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
stars: abundances, stars: kinematics and dynamics, Galaxy: disc, Galaxy:, evolution, Galaxy: formation, Galaxy: kinematics and dynamics
in
Monthly Notices of the Royal Astronomical Society
volume
444
issue
1
pages
515 - 526
publisher
Wiley-Blackwell
external identifiers
  • wos:000342925100040
  • scopus:84913534536
ISSN
1365-2966
DOI
10.1093/mnras/stu1435
language
English
LU publication?
yes
id
2f2ad568-792b-4f2e-888a-58cee6a5f90f (old id 4784098)
date added to LUP
2014-11-21 12:16:25
date last changed
2017-09-17 03:11:53
@article{2f2ad568-792b-4f2e-888a-58cee6a5f90f,
  abstract     = {The Milky Way is expected to host an accreted disc of stars and dark matter. This forms as massive greater than or similar to 1 : 10 mergers are preferentially dragged towards the disc plane by dynamical friction and then tidally shredded. The accreted disc likely contributes only a tiny fraction of the MilkyWay's thin and thick stellar disc. However, it is interesting because (i) its associated 'dark disc' has important implications for experiments hoping to detect a dark matter particle in the laboratory; and (ii) the presence or absence of such a disc constrains the merger history of our Galaxy. In this work, we develop a chemodynamical template to hunt for the accreted disc. We apply our template to the high-resolution spectroscopic sample from Ruchti et al., finding at present no evidence for accreted disc stars. Our results are consistent with a quiescent Milky Way with no greater than or similar to 1 : 10 mergers since the disc formed and a correspondingly light ` dark disc'. However, we caution that while our method can robustly identify accreted stars, our incomplete stellar sample makes it more challenging to definitively rule them out. Larger unbiased stellar samples will be required for this.},
  author       = {Ruchti, Gregory and Read, Justin I. and Feltzing, Sofia and Pipino, Antonio and Bensby, Thomas},
  issn         = {1365-2966},
  keyword      = {stars: abundances,stars: kinematics and dynamics,Galaxy: disc,Galaxy:,evolution,Galaxy: formation,Galaxy: kinematics and dynamics},
  language     = {eng},
  number       = {1},
  pages        = {515--526},
  publisher    = {Wiley-Blackwell},
  series       = {Monthly Notices of the Royal Astronomical Society},
  title        = {The hunt for the Milky Way's accreted disc},
  url          = {http://dx.doi.org/10.1093/mnras/stu1435},
  volume       = {444},
  year         = {2014},
}