We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.

Durham Research Online
You are in:

Spin flips - II. Evolution of dark matter halo spin orientation, and its correlation with major mergers.

Bett, P. E. and Frenk, C. S. (2016) 'Spin flips - II. Evolution of dark matter halo spin orientation, and its correlation with major mergers.', Monthly notices of the Royal Astronomical Society., 461 (2). pp. 1338-1355.


We expand our previous study on the relationship between changes in the orientation of the angular momentum vector of dark matter haloes (‘spin flips’) and changes in their mass, to cover the full range of halo masses in a simulation cube of length 100 h−1 Mpc. Since strong disturbances to a halo (such as might be indicated by a large change in the spin direction) are likely also to disturb the galaxy evolving within, spin flips could be a mechanism for galaxy morphological transformation without involving major mergers. We find that 35 per cent of haloes have, at some point in their lifetimes, had a spin flip of at least 45° that does not coincide with a major merger. Over 75 per cent of large spin flips coincide with non-major mergers; only a quarter coincide with major mergers. We find a similar picture for changes to the inner halo spin orientation, although here there is an increased likelihood of a flip occurring. Changes in halo angular momentum orientation, and other such measures of halo perturbation, are therefore very important quantities to consider, in addition to halo mergers, when modelling the formation and evolution of galaxies and confronting such models with observations.

Item Type:Article
Full text:(VoR) Version of Record
Download PDF
Publisher Web site:
Publisher statement:This article has been accepted for publication in Monthly notices of the Royal Astronomical Society ©: 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Date accepted:08 June 2016
Date deposited:12 October 2016
Date of first online publication:10 June 2016
Date first made open access:12 October 2016

Save or Share this output

Look up in GoogleScholar