St Andrews Research Repository

St Andrews University Home
View Item 
  •   St Andrews Research Repository
  • University of St Andrews Research
  • University of St Andrews Research
  • University of St Andrews Research
  • View Item
  •   St Andrews Research Repository
  • University of St Andrews Research
  • University of St Andrews Research
  • University of St Andrews Research
  • View Item
  •   St Andrews Research Repository
  • University of St Andrews Research
  • University of St Andrews Research
  • University of St Andrews Research
  • View Item
  • Login
JavaScript is disabled for your browser. Some features of this site may not work without it.

Dynamical history of the Local Group in ΛCDM II − including external perturbers In 3D

Thumbnail
View/Open
Banik_2017_MNRAS_CDM_2180.pdf (2.567Mb)
Date
05/2017
Author
Banik, Indranil
Zhao, Hongsheng
Keywords
Galaxies: groups: individual: Local Group
Galaxy: kinematics and dynamics
Dark Matter
Methods: numerical: data analysis
Cosmology: cosmological parameters
QB Astronomy
QC Physics
NDAS
Metadata
Show full item record
Altmetrics Handle Statistics
Altmetrics DOI Statistics
Abstract
We attempt to fit the observed radial velocities (RVs) of ~30 Local Group (LG) galaxies using a 3D dynamical model of it and its immediate environment within the context of the standard cosmological paradigm, ΛCDM. This extends and confirms the basic results of our previous axisymmetric investigation of the LG (MNRAS, 459, 2237). We find that there remains a tendency for observed RVs to exceed those predicted by our best-fitting model. The typical mismatch is slightly higher than in our 2D model, with a root mean square value of ~50 km/s. Our main finding is that including the 3D distribution of massive perturbing dark matter halos is unlikely to help greatly with the high velocity galaxy problem. Nonetheless, the 2D and 3D results differ in several other ways such as which galaxies' RVs are most problematic and the preferred values of parameters common to both models. The anomalously high RVs of several LG dwarfs may be better explained if the Milky Way (MW) and Andromeda (M31) were once moving much faster than in our models. This would allow LG dwarfs to gain very high RVs via gravitational slingshot encounters with a massive fast-moving galaxy. Such a scenario is possible in some modified gravity theories, especially those which require the MW and M31 to have previously undergone a close flyby. In a ΛCDM context, however, this scenario is not feasible as the resulting dynamical friction would cause a rapid merger.
Citation
Banik , I & Zhao , H 2017 , ' Dynamical history of the Local Group in ΛCDM II − including external perturbers In 3D ' , Monthly Notices of the Royal Astronomical Society , vol. 467 , no. 2 , pp. 2180-2198 . https://doi.org/10.1093/mnras/stx151
Publication
Monthly Notices of the Royal Astronomical Society
Status
Peer reviewed
DOI
https://doi.org/10.1093/mnras/stx151
ISSN
0035-8711
Type
Journal article
Rights
© 2017, the Author(s). This work has been made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at academic.oup.com / https://doi.org/10.1093/mnras/stx151
Description
IB is supported by a Science and Technology Facilities Council studentship.
Collections
  • University of St Andrews Research
URI
http://hdl.handle.net/10023/10138

Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

Advanced Search

Browse

All of RepositoryCommunities & CollectionsBy Issue DateNamesTitlesSubjectsClassificationTypeFunderThis CollectionBy Issue DateNamesTitlesSubjectsClassificationTypeFunder

My Account

Login

Open Access

To find out how you can benefit from open access to research, see our library web pages and Open Access blog. For open access help contact: openaccess@st-andrews.ac.uk.

Accessibility

Read our Accessibility statement.

How to submit research papers

The full text of research papers can be submitted to the repository via Pure, the University's research information system. For help see our guide: How to deposit in Pure.

Electronic thesis deposit

Help with deposit.

Repository help

For repository help contact: Digital-Repository@st-andrews.ac.uk.

Give Feedback

Cookie policy

This site may use cookies. Please see Terms and Conditions.

Usage statistics

COUNTER-compliant statistics on downloads from the repository are available from the IRUS-UK Service. Contact us for information.

© University of St Andrews Library

University of St Andrews is a charity registered in Scotland, No SC013532.

  • Facebook
  • Twitter