eprintid: 27265
rev_number: 16
eprint_status: archive
userid: 4707
dir: disk0/00/02/72/65
datestamp: 2019-10-22 13:05:29
lastmod: 2019-11-07 12:08:34
status_changed: 2019-10-22 13:05:29
type: doctoralThesis
metadata_visibility: show
creators_name: Leung, Ying Chi
title: Constraining the nature of dark matter in galaxies with multi-tracer dynamical models
subjects: 520
divisions: 130001
adv_faculty: af-11
abstract: The detailed mass distribution in galaxies provides important constraints on the
nature of dark matter (DM), especially in relation to the baryonic content and
feedback efficiency of a galaxy. In this thesis I use multiple kinematic tracers and a
diverse set of dynamical models to simultaneously constrain DM density profiles, halo
shapes and the evolutionary history of galaxies. I first show that the most common
and advanced stellar dynamical models can reproduce the circular velocities (as
traced independently by molecular gas rotation curves), to within ⇠10% accuracy.
I further use high resolution observations to understand the sources (gravitational,
feedback driven) of high velocity dispersion ionised gas. By incorporating realistic
birth conditions for globular clusters (GCs) and flexible, self-consistent velocity
distribution functions for the Fornax dSph, I am able to understand the survival
of its five GCs. The comprehensive evolutionary model suggests that Fornax has
a large DM core (&1.5 kpc) and has undergone a past merger of mass ratio ⇠1:2
to 1:5. Finally, by combining stellar and gas kinematic tracers together in a single
dynamical model, I provide evidence that the isolated dwarf irregular galaxy WLM
has a DM halo that has both an inner density core (! ⇠ 0.3±0.1), and a prolate axis
ratio of 2:1. The recovered orbit structure (tangential anisotropic) is very similar
to nearby dSph galaxies - suggesting that internal processes rather than tidal origin
may lead to this dynamical configuration. The DM halo profile is consistent with
the ⇤CDM cosmological picture when baryonic feedback is included. The prolate
geometry is difficult for MOND and at the same time challenges self-interacting
DM (SIDM) theories to create a thermalised DM core of the observed size, without
sphericalising the halo. From both the dynamical models on WLM and Fornax, I
am able to provide constraints on the particle mass of Bose-Einstein condensate
DM models to 1.1 − 1.3 ⇥ 10−22 eV/c2, and interaction cross section for (velocity
independent) SIDM particles of 0.8 . "/mSIDM . 3.1 cm2/g - though it remains to
be seen that these can produce the proper core size and shape in the DM halos we
find. Application of these new techniques and models to more galaxies will provide
even tighter constraints on dark matter particle models.
date: 2019
id_scheme: DOI
id_number: 10.11588/heidok.00027265
ppn_swb: 1680795724
own_urn: urn:nbn:de:bsz:16-heidok-272659
date_accepted: 2019-07-16
advisor: HASH(0x55611cd16fe8)
language: eng
bibsort: LEUNGYINGCCONSTRAINI2019
full_text_status: public
place_of_pub: Heidelberg
citation:   Leung, Ying Chi  (2019) Constraining the nature of dark matter in galaxies with multi-tracer dynamical models.  [Dissertation]     
document_url: https://archiv.ub.uni-heidelberg.de/volltextserver/27265/1/Thesis_gigileung.pdf