Where are the Population III star relics in the simulated Milky Way analogues?

Fuente: arXiv
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Hauptverfasser: Yang, Hang, Gao, Liang, Guo, Qi, Li, Haining, Shao, Shi, Zhao, Gang
Format: Preprint
Veröffentlicht: 2025
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author Yang, Hang
Gao, Liang
Guo, Qi
Li, Haining
Shao, Shi
Zhao, Gang
author_facet Yang, Hang
Gao, Liang
Guo, Qi
Li, Haining
Shao, Shi
Zhao, Gang
contents Using 6 Milky Way analogues with two different numerical resolutions from the Auriga simulation, we investigate the total mass, spatial distribution and kinematics of the Population III star relics in the Milky Way analogues at $z=0$. These relics (primarily second generation stars) formed over a wide redshift range, from about $z=22$ to $z=4$, with an average formation redshift of $z \sim 10.0$, and comprise about $2\times10^{-5}$ of the entire galactic stellar population. The disk and bulge components host only a small fraction of these relics, contributing less than $12$ percent in total. The stellar halo, in particular the outer stellar halo of which galactic radius $r>30$ kpc, hosts the largest fraction (about 46 percent on average), with an average of one relic star for per $4,000$ to $10,000$ stars, making it a promising region for observational searches. Additionally, around $18$ percent of the Population III star relics are found in satellite galaxies, with smaller and older satellite galaxies tending to contain a higher proportion of these stars. Thus, low-mass and early-formed satellite galaxies are also ideal targets for finding such relics, although some satellite galaxies may lack them entirely. The spatial distribution and kinematics of these stars show good numerical convergence across different simulation resolutions. Our results provide valuable guidance for searches of the Population III star relics and offer insights for interpreting findings from ongoing and future stellar archaeology surveys.
format Preprint
id arxiv_https___arxiv_org_abs_2502_17088
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Where are the Population III star relics in the simulated Milky Way analogues?
Yang, Hang
Gao, Liang
Guo, Qi
Li, Haining
Shao, Shi
Zhao, Gang
Astrophysics of Galaxies
Using 6 Milky Way analogues with two different numerical resolutions from the Auriga simulation, we investigate the total mass, spatial distribution and kinematics of the Population III star relics in the Milky Way analogues at $z=0$. These relics (primarily second generation stars) formed over a wide redshift range, from about $z=22$ to $z=4$, with an average formation redshift of $z \sim 10.0$, and comprise about $2\times10^{-5}$ of the entire galactic stellar population. The disk and bulge components host only a small fraction of these relics, contributing less than $12$ percent in total. The stellar halo, in particular the outer stellar halo of which galactic radius $r>30$ kpc, hosts the largest fraction (about 46 percent on average), with an average of one relic star for per $4,000$ to $10,000$ stars, making it a promising region for observational searches. Additionally, around $18$ percent of the Population III star relics are found in satellite galaxies, with smaller and older satellite galaxies tending to contain a higher proportion of these stars. Thus, low-mass and early-formed satellite galaxies are also ideal targets for finding such relics, although some satellite galaxies may lack them entirely. The spatial distribution and kinematics of these stars show good numerical convergence across different simulation resolutions. Our results provide valuable guidance for searches of the Population III star relics and offer insights for interpreting findings from ongoing and future stellar archaeology surveys.
title Where are the Population III star relics in the simulated Milky Way analogues?
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2502.17088