Skip to main content

Research Repository

Advanced Search

To β or not to β: can higher-order Jeans analysis break the mass–anisotropy degeneracy in simulated dwarfs?

Genina, A.; Read, J.I.; Frenk, C.S.; Cole, S.; Benítez-Llambay, A.; Ludlow, A.D.; Navarro, J.F.; Oman, K.A.; Robertson, A.

To β or not to β: can higher-order Jeans analysis break the mass–anisotropy degeneracy in simulated dwarfs? Thumbnail


Authors

A. Genina

J.I. Read

A. Benítez-Llambay

A.D. Ludlow

J.F. Navarro

Profile Image

Dr Kyle Oman kyle.a.oman@durham.ac.uk
Assistant Professor - Royal Society Dorothy Hodgkin Fellow



Abstract

We test a non-parametric higher-order Jeans analysis method, GRAVSPHERE, on 32 simulated dwarf galaxies comparable to classical Local Group dwarfs like Fornax. The galaxies are selected from the APOSTLE suite of cosmological hydrodynamics simulations with Cold Dark Matter (CDM) and Self-Interacting Dark Matter (SIDM) models, allowing us to investigate cusps and cores in density distributions. We find that, for CDM dwarfs, the recovered enclosed mass profiles have a bias of no more than 10 per cent, with a 50 per cent scatter in the inner regions and a 20 per cent scatter near the half-light radius, consistent with standard mass estimators. The density profiles are also recovered with a bias of no more than 10 per cent and a scatter of 30 per cent in the inner regions. For SIDM dwarfs, the mass and density profiles are recovered within our 95 per cent confidence intervals, but are biased towards cuspy dark matter distributions. This is mainly due to a lack of sufficient constraints from the data. We explore the sources of scatter in the accuracy of the recovered profiles and suggest a χ2 statistic to separate successful models from biased ones. Finally, we show that the uncertainties on the mass profiles obtained with GRAVSPHERE are smaller than those for comparable Jeans methods, and that they can be further improved if stronger priors, motivated by cosmological simulations, are placed on the velocity anisotropy. We conclude that GRAVSPHERE is a promising Jeans-based approach for modelling dark matter distributions in dwarf galaxies.

Citation

Genina, A., Read, J., Frenk, C., Cole, S., Benítez-Llambay, A., Ludlow, A., …Robertson, A. (2020). To β or not to β: can higher-order Jeans analysis break the mass–anisotropy degeneracy in simulated dwarfs?. Monthly Notices of the Royal Astronomical Society, 498(1), 144-163. https://doi.org/10.1093/mnras/staa2352

Journal Article Type Article
Acceptance Date Aug 3, 2020
Online Publication Date Aug 14, 2020
Publication Date 2020-10
Deposit Date Aug 18, 2020
Publicly Available Date Sep 18, 2020
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 498
Issue 1
Pages 144-163
DOI https://doi.org/10.1093/mnras/staa2352

Files

Published Journal Article (3.9 Mb)
PDF

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.







You might also like



Downloadable Citations