Subhalos in Galaxy Clusters: Coherent Accretion and Internal Orbits

Fuente: arXiv
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Autori principali: Han, Chi, Wang, Kuan, Avestruz, Camille, Anbajagane, Dhayaa
Natura: Preprint
Pubblicazione: 2023
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author Han, Chi
Wang, Kuan
Avestruz, Camille
Anbajagane, Dhayaa
author_facet Han, Chi
Wang, Kuan
Avestruz, Camille
Anbajagane, Dhayaa
contents Subhalo dynamics in galaxy cluster host halos govern the observed distribution and properties of cluster member galaxies. We use the IllustrisTNG simulation to investigate the accretion and orbits of subhalos found in cluster-size halos. We find that the median change in the major axis direction of cluster-size host halos is approximately $80$ degrees between $a\sim0.1$ and present-day. We identify coherent regions in the angular distribution of subhalo accretion, and $\sim68\%$ of accreted subhalos enter their host halo through $\sim38\%$ of the surface area at the virial radius. The majority of galaxy clusters in the sample have $\sim2$ such coherent regions. We further measure angular orbits of subhalos with respect to the host major axis and use a clustering algorithm to identify distinct orbit modes with varying oscillation timescales. The orbit modes correlate with subhalo accretion conditions. Subhalos in orbit modes with shorter oscillations tend to have lower peak masses and accretion directions somewhat more aligned with the major axis. One orbit mode, exhibiting the least oscillatory behavior, largely consists of subhalos that accrete near the plane perpendicular to the host halo major axis. Our findings are consistent with expectations from inflow from major filament structures and internal dynamical friction: most subhalos accrete through coherent regions, and more massive subhalos experience fewer orbits after accretion. Our work offers a unique quantification of subhalo dynamics that can be connected to how the intracluster medium strips and quenches cluster galaxies.
format Preprint
id arxiv_https___arxiv_org_abs_2312_08337
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Subhalos in Galaxy Clusters: Coherent Accretion and Internal Orbits
Han, Chi
Wang, Kuan
Avestruz, Camille
Anbajagane, Dhayaa
Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
Subhalo dynamics in galaxy cluster host halos govern the observed distribution and properties of cluster member galaxies. We use the IllustrisTNG simulation to investigate the accretion and orbits of subhalos found in cluster-size halos. We find that the median change in the major axis direction of cluster-size host halos is approximately $80$ degrees between $a\sim0.1$ and present-day. We identify coherent regions in the angular distribution of subhalo accretion, and $\sim68\%$ of accreted subhalos enter their host halo through $\sim38\%$ of the surface area at the virial radius. The majority of galaxy clusters in the sample have $\sim2$ such coherent regions. We further measure angular orbits of subhalos with respect to the host major axis and use a clustering algorithm to identify distinct orbit modes with varying oscillation timescales. The orbit modes correlate with subhalo accretion conditions. Subhalos in orbit modes with shorter oscillations tend to have lower peak masses and accretion directions somewhat more aligned with the major axis. One orbit mode, exhibiting the least oscillatory behavior, largely consists of subhalos that accrete near the plane perpendicular to the host halo major axis. Our findings are consistent with expectations from inflow from major filament structures and internal dynamical friction: most subhalos accrete through coherent regions, and more massive subhalos experience fewer orbits after accretion. Our work offers a unique quantification of subhalo dynamics that can be connected to how the intracluster medium strips and quenches cluster galaxies.
title Subhalos in Galaxy Clusters: Coherent Accretion and Internal Orbits
topic Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2312.08337