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Main Authors: Zhang, Xiao-Ya, Huang, Song, Gu, Meng
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2507.22602
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author Zhang, Xiao-Ya
Huang, Song
Gu, Meng
author_facet Zhang, Xiao-Ya
Huang, Song
Gu, Meng
contents We investigate the connection between stellar mass distribution, assembly history, and star formation timescales in low-redshift massive early-type galaxies (ETGs) by combining deep LegacySurvey imaging with MaNGA's spatially resolved spectroscopy. Focusing on stellar population properties, especially the [Mg/Fe] abundance ratio, we analyze stacked spectra using both absorption line indices and full-spectrum fitting. We find that, among massive ETGs with identical average stellar mass distributions beyond 20 kpc, those with higher central velocity dispersion ($σ_{cen}$) are older and more $α$-enhanced, suggesting a connection between the in-situ star formation in the past and the central gravitational potential today for massive ETGs with a similar stellar accretion history. Conversely, at fixed $σ_{cen}$ and total stellar mass, galaxies with more extended stellar halos show lower [Fe/H], higher [Mg/Fe], and older ages, indicating an intriguing link between early starburst and quenching and later ex-situ assembly. These results demonstrate that the evolution of massive galaxies cannot be fully described by simple scaling relations alone, as the interplay between in-situ star formation and ex-situ accretion leaves distinct imprints in both their inner and outer stellar populations. Our findings highlight the importance of extending stellar population studies to large radii and underscore the scientific potential of next-generation IFU surveys and deep, high-resolution spectroscopy for probing the galaxy-halo connection.
format Preprint
id arxiv_https___arxiv_org_abs_2507_22602
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A MaNGA about the Legacy I: Connecting the Assembly of Stellar Halo with the Average Star Formation History in Low-Redshift Massive Galaxies
Zhang, Xiao-Ya
Huang, Song
Gu, Meng
Astrophysics of Galaxies
We investigate the connection between stellar mass distribution, assembly history, and star formation timescales in low-redshift massive early-type galaxies (ETGs) by combining deep LegacySurvey imaging with MaNGA's spatially resolved spectroscopy. Focusing on stellar population properties, especially the [Mg/Fe] abundance ratio, we analyze stacked spectra using both absorption line indices and full-spectrum fitting. We find that, among massive ETGs with identical average stellar mass distributions beyond 20 kpc, those with higher central velocity dispersion ($σ_{cen}$) are older and more $α$-enhanced, suggesting a connection between the in-situ star formation in the past and the central gravitational potential today for massive ETGs with a similar stellar accretion history. Conversely, at fixed $σ_{cen}$ and total stellar mass, galaxies with more extended stellar halos show lower [Fe/H], higher [Mg/Fe], and older ages, indicating an intriguing link between early starburst and quenching and later ex-situ assembly. These results demonstrate that the evolution of massive galaxies cannot be fully described by simple scaling relations alone, as the interplay between in-situ star formation and ex-situ accretion leaves distinct imprints in both their inner and outer stellar populations. Our findings highlight the importance of extending stellar population studies to large radii and underscore the scientific potential of next-generation IFU surveys and deep, high-resolution spectroscopy for probing the galaxy-halo connection.
title A MaNGA about the Legacy I: Connecting the Assembly of Stellar Halo with the Average Star Formation History in Low-Redshift Massive Galaxies
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2507.22602