Linking Detectable Tidal Features to Stellar Halo Growth: An Integrated Analysis of the Outskirts of Massive Early-type Galaxies
Abstract
Motivated by the finding that massive galaxies with tidal features (GwT) are preferentially found in low-density environments, one wonders whether this trend arises from enhanced debris survivability or from more active mass-assembly histories. If driven by the latter, structural signatures, such as more developed stellar halos, should also form through cumulative accretion. To address this, we analyze azimuthally averaged surface-brightness profiles of 436 massive early-type galaxies from the DESI Legacy Imaging Survey, comparing the median-stacked profiles of galaxies with tidal features to those without. We find that, after resampling by stellar mass and environmental density, a subtle but systematic structural divergence emerges in the galaxy outskirts (r>5× r50). Specifically, the GwT population in the lower-density & higher-mass regime exhibits a relative intensity excess. This suggests that more developed stellar halos have formed, likely due to longer and/or more significant accretion events. In contrast, those in the higher-density & lower-mass regime show a relative deficiency in intensity, which is reasonable to interpret as a result of structural disruption from environmental effects rather than a lack of cumulative accretion. Our findings suggest that visible tidal features−particularly in massive systems within quiet environments−do not merely reflect recent stochastic accretion events but also hint at the long-term assembly history of galaxies. This work is a depth-limited study that offers a glimpse into an integrated analysis of tidal debris and stellar halos, thereby introducing a novel pathway to unravel the complex assembly histories of galaxies.
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BibTeX
@misc{byun2026linking,
title = {{Linking Detectable Tidal Features to Stellar Halo Growth: An Integrated Analysis of the Outskirts of Massive Early-type Galaxies}},
author = {Woowon Byun and Yongmin Yoon and Kyungwon Chun and Jongwan Ko and Jae-Woo Kim},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.34966},
eprint = {2610.34966},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.34966},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Linking Detectable Tidal Features to Stellar Halo Growth: An Integrated Analysis of the Outskirts of Massive Early-type Galaxies
AU - Woowon Byun
AU - Yongmin Yoon
AU - Kyungwon Chun
AU - Jongwan Ko
AU - Jae-Woo Kim
PY - 2026
DA - 2026/10/26
PB - arXiv
DO - 10.48550/arxiv.2610.34966
UR - https://arxiv.org/abs/2610.34966
AB - Motivated by the finding that massive galaxies with tidal features (GwT) are preferentially found in low-density environments, one wonders whether this trend arises from enhanced debris survivability or from more active mass-assembly histories. If driven by the latter, structural signatures, such as more developed stellar halos, should also form through cumulative accretion. To address this, we analyze azimuthally averaged surface-brightness profiles of 436 massive early-type galaxies from the DESI Legacy Imaging Survey, comparing the median-stacked profiles of galaxies with tidal features to those without. We find that, after resampling by stellar mass and environmental density, a subtle but systematic structural divergence emerges in the galaxy outskirts (r>5× r_50). Specifically, the GwT population in the lower-density & higher-mass regime exhibits a relative intensity excess. This suggests that more developed stellar halos have formed, likely due to longer and/or more significant accretion events. In contrast, those in the higher-density & lower-mass regime show a relative deficiency in intensity, which is reasonable to interpret as a result of structural disruption from environmental effects rather than a lack of cumulative accretion. Our findings suggest that visible tidal features−particularly in massive systems within quiet environments−do not merely reflect recent stochastic accretion events but also hint at the long-term assembly history of galaxies. This work is a depth-limited study that offers a glimpse into an integrated analysis of tidal debris and stellar halos, thereby introducing a novel pathway to unravel the complex assembly histories of galaxies.
ER -