Statistical Predictions of the Accreted Stellar Halos around Milky Way-Like Galaxies

Fuente: arXiv
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Autori principali: Monzon, J. Sebastian, Bosch, Frank C. van den, Rey, Martin P.
Natura: Preprint
Pubblicazione: 2026
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author Monzon, J. Sebastian
Bosch, Frank C. van den
Rey, Martin P.
author_facet Monzon, J. Sebastian
Bosch, Frank C. van den
Rey, Martin P.
contents In the $Λ$CDM paradigm, stellar halos form through the accretion and disruption of satellite galaxies. We introduce new semi-analytic modeling within the SatGen framework to track the ex-situ stellar components of Milky Way--like galaxies across large ensembles of merger trees, enabling a statistical study of the stochastic nature of galaxy assembly. We find that accreted stellar halos are typically built by only a few progenitors and are highly sensitive to the fate of the most massive satellite, producing order-of-magnitude variations in accreted stellar halo mass even at fixed host halo mass. Different stellar components trace distinct phases of host halo growth: central and accreted stellar mass correlate most strongly with early assembly, while surviving satellites trace more recent accretion. Finally, using Random Forest Regression, we quantify how well observable galaxy properties can recover halo assembly histories, providing a framework for interpreting upcoming low-surface-brightness observations of stellar halos.
format Preprint
id arxiv_https___arxiv_org_abs_2601_18954
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Statistical Predictions of the Accreted Stellar Halos around Milky Way-Like Galaxies
Monzon, J. Sebastian
Bosch, Frank C. van den
Rey, Martin P.
Astrophysics of Galaxies
In the $Λ$CDM paradigm, stellar halos form through the accretion and disruption of satellite galaxies. We introduce new semi-analytic modeling within the SatGen framework to track the ex-situ stellar components of Milky Way--like galaxies across large ensembles of merger trees, enabling a statistical study of the stochastic nature of galaxy assembly. We find that accreted stellar halos are typically built by only a few progenitors and are highly sensitive to the fate of the most massive satellite, producing order-of-magnitude variations in accreted stellar halo mass even at fixed host halo mass. Different stellar components trace distinct phases of host halo growth: central and accreted stellar mass correlate most strongly with early assembly, while surviving satellites trace more recent accretion. Finally, using Random Forest Regression, we quantify how well observable galaxy properties can recover halo assembly histories, providing a framework for interpreting upcoming low-surface-brightness observations of stellar halos.
title Statistical Predictions of the Accreted Stellar Halos around Milky Way-Like Galaxies
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2601.18954