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Main Authors: Shields, Tristen, Salazar, Edgar M., Rozo, Eduardo, Adya, Aakanksha, Osinga, Calvin, Vladimir, Ze'ev
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2507.00410
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author Shields, Tristen
Salazar, Edgar M.
Rozo, Eduardo
Adya, Aakanksha
Osinga, Calvin
Vladimir, Ze'ev
author_facet Shields, Tristen
Salazar, Edgar M.
Rozo, Eduardo
Adya, Aakanksha
Osinga, Calvin
Vladimir, Ze'ev
contents Among the most fundamental properties of a dark matter halo is its density profile. Motivated by the recent proposal by García et al. [R. García et. al., MNRAS 521, 2464 (2023)] to define a dynamical halo as the collection of orbiting particles in a gravitationally bound structure, we characterize the mean and scatter of the orbiting profile of dynamical halos as a function of their orbiting mass. We demonstrate that the orbiting profile of individual halos at fixed mass depends on a single dynamical variable -- the halo radius $r_{\rm h}$ -- which characterizes the spatial extent of the profile. The scatter in halo radius at fixed orbiting mass is $\approx 16\%$. Only a small fraction of this scatter arises due to differences in halo formation time, with late-forming halos being more compact (smaller halo radii). Accounting for this additional correlation results in an $\approx 11\%$ scatter in halo radius at fixed mass and halo formation time.
format Preprint
id arxiv_https___arxiv_org_abs_2507_00410
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Density Profile of Dynamical Halos
Shields, Tristen
Salazar, Edgar M.
Rozo, Eduardo
Adya, Aakanksha
Osinga, Calvin
Vladimir, Ze'ev
Cosmology and Nongalactic Astrophysics
Among the most fundamental properties of a dark matter halo is its density profile. Motivated by the recent proposal by García et al. [R. García et. al., MNRAS 521, 2464 (2023)] to define a dynamical halo as the collection of orbiting particles in a gravitationally bound structure, we characterize the mean and scatter of the orbiting profile of dynamical halos as a function of their orbiting mass. We demonstrate that the orbiting profile of individual halos at fixed mass depends on a single dynamical variable -- the halo radius $r_{\rm h}$ -- which characterizes the spatial extent of the profile. The scatter in halo radius at fixed orbiting mass is $\approx 16\%$. Only a small fraction of this scatter arises due to differences in halo formation time, with late-forming halos being more compact (smaller halo radii). Accounting for this additional correlation results in an $\approx 11\%$ scatter in halo radius at fixed mass and halo formation time.
title The Density Profile of Dynamical Halos
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2507.00410