From particles to orbits : precise dark matter density profiles using dynamical information
(2024) In Monthly Notices of the Royal Astronomical Society 527(3). p.9250-9262- Abstract
We introduce a new method to calculate dark matter halo density profiles from simulations. Each particle is ‘smeared’ over its orbit to obtain a dynamical profile that is averaged over a dynamical time, in contrast to the traditional approach of binning particles based on their instantaneous positions. The dynamical and binned profiles are in good agreement, with the dynamical approach showing a significant reduction in Poisson noise in the innermost regions. We find that the inner cusps of the new dynamical profiles continue inward all the way to the softening radius, reproducing the central density profile of higher resolution simulations within the 95 per cent confidence intervals, for haloes in virial equilibrium. Folding in... (More)
We introduce a new method to calculate dark matter halo density profiles from simulations. Each particle is ‘smeared’ over its orbit to obtain a dynamical profile that is averaged over a dynamical time, in contrast to the traditional approach of binning particles based on their instantaneous positions. The dynamical and binned profiles are in good agreement, with the dynamical approach showing a significant reduction in Poisson noise in the innermost regions. We find that the inner cusps of the new dynamical profiles continue inward all the way to the softening radius, reproducing the central density profile of higher resolution simulations within the 95 per cent confidence intervals, for haloes in virial equilibrium. Folding in dynamical information thus provides a new approach to improve the precision of dark matter density profiles at small radii, for minimal computational cost. Our technique makes two key assumptions that the halo is in equilibrium (phase mixed) and the potential is spherically symmetric. We discuss why the method is successful despite strong violations of spherical symmetry in the centres of haloes, and explore how substructures disturb equilibrium at large radii.
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- author
- Muni, Claudia ; Pontzen, Andrew ; Sanders, Jason L. ; Rey, Martin P. LU ; Read, Justin I. and Agertz, Oscar LU
- organization
- publishing date
- 2024
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- dark matter, galaxies: haloes, galaxies: kinematics and dynamics
- in
- Monthly Notices of the Royal Astronomical Society
- volume
- 527
- issue
- 3
- pages
- 13 pages
- publisher
- Oxford University Press
- external identifiers
-
- scopus:85181849983
- ISSN
- 0035-8711
- DOI
- 10.1093/mnras/stad3835
- language
- English
- LU publication?
- yes
- id
- 1b64c12b-4419-404d-a0ae-b830fce07f2f
- date added to LUP
- 2024-02-08 13:30:42
- date last changed
- 2024-02-08 13:32:12
@article{1b64c12b-4419-404d-a0ae-b830fce07f2f,
abstract = {{<p>We introduce a new method to calculate dark matter halo density profiles from simulations. Each particle is ‘smeared’ over its orbit to obtain a dynamical profile that is averaged over a dynamical time, in contrast to the traditional approach of binning particles based on their instantaneous positions. The dynamical and binned profiles are in good agreement, with the dynamical approach showing a significant reduction in Poisson noise in the innermost regions. We find that the inner cusps of the new dynamical profiles continue inward all the way to the softening radius, reproducing the central density profile of higher resolution simulations within the 95 per cent confidence intervals, for haloes in virial equilibrium. Folding in dynamical information thus provides a new approach to improve the precision of dark matter density profiles at small radii, for minimal computational cost. Our technique makes two key assumptions that the halo is in equilibrium (phase mixed) and the potential is spherically symmetric. We discuss why the method is successful despite strong violations of spherical symmetry in the centres of haloes, and explore how substructures disturb equilibrium at large radii.</p>}},
author = {{Muni, Claudia and Pontzen, Andrew and Sanders, Jason L. and Rey, Martin P. and Read, Justin I. and Agertz, Oscar}},
issn = {{0035-8711}},
keywords = {{dark matter; galaxies: haloes; galaxies: kinematics and dynamics}},
language = {{eng}},
number = {{3}},
pages = {{9250--9262}},
publisher = {{Oxford University Press}},
series = {{Monthly Notices of the Royal Astronomical Society}},
title = {{From particles to orbits : precise dark matter density profiles using dynamical information}},
url = {{http://dx.doi.org/10.1093/mnras/stad3835}},
doi = {{10.1093/mnras/stad3835}},
volume = {{527}},
year = {{2024}},
}