Co-evolution of Supermassive Black Holes and their Host L* galaxies: implications for Milky Way and M31

[2605.16501] Co-evolution of Supermassive Black Holes and their Host L* galaxies: implications for Milky Way and M31 Skip to main content Search Submit Donate Log in Astrophysics > Astrophysics of Galaxies arXiv:2605.16501 (astro-ph) [Submitted on 15 May 2026 ( v1 ), last revised 27 Aug 2026 (this version, v2)] Title: Co-evolution of Supermassive Black Holes and their Host L* galaxies: implications for Milky Way and M31 Authors: Salvador E. Grimozzi , Maria Emilia De Rossi , Andreea S. Font View PDF HTML (experimental) Abstract: We investigate the origin of the scatter in supermassive black hole (BH) masses among L* galaxies, using the ARTEMIS and EAGLE simulations. We classify galaxies by their central BH-to-stellar mass ratios and track systems with the lowest and highest ratios (LBH and HBH, respectively). Although these populations have similar properties at z~ 2, they diverge significantly towards lower redshifts. LBH galaxies maintain higher gas fractions and sustain star formation, while HBHs form stars earlier, experience faster BH growth, more efficient feedback, and subsequent quenching. The simulations broadly match the observed scatter in the BH masses and galaxy morphologies in the L* regime, linking it to differences in merger histories. Galaxies with more active merger histories host more massive BHs at present and are predominantly elliptical, whereas those with quieter histories host lower-mass BHs and tend to be disc-like. Mergers induce BH growth through enhanced gas accretion and direct BH-BH coalescences. However, these channels operate differently: in HBH galaxies, BHs grow primarily (~90%) through gas accretion, whereas in LBHs they grow through both gas accretion and BH--BH mergers, in comparable fractions. These results suggest that the contrasting BH masses in the Milky Way and M31 may arise from differences in their merger histories. We also investigate the role of feedback from supernovae (SN) versus active galactic nuclei (AGN) on these scales. AGN feedback appears to be the primary mechanism responsible for quenching MW-mass systems, although SN feedback remains the dominant regulator of their overall evolution. Comments: 16 pages, 11 figures, accepted to MNRAS Subjects: Astrophysics of Galaxies (astro-ph.GA) Cite as: arXiv:2605.16501 [astro-ph.GA] (or arXiv:2605.16501v2 [astro-ph.GA] for this version) https://doi.org/10.48550/arXiv.2605.16501 Focus to learn more arXiv-issued DOI via DataCite Journal reference: Mon Not R Astron Soc (2026) Related DOI : https://doi.org/10.1093/mnras/stag1666 Focus to learn more DOI(s) linking to related resources Submission history From: Andreea Font [ view email ] [v1] Fri, 15 May 2026 18:00:35 UTC (3,647 KB) [v2] Thu, 27 Aug 2026 22:07:57 UTC (3,968 KB) Full-text links: Access Paper: View PDF HTML (experimental) TeX Source view license Current browse context: astro-ph.GA < prev | next > new | recent | 2026-05 Change to browse by: astro-ph References & Citations SciX Google Scholar Semantic Scholar export BibTeX citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer ( What is the Explorer? ) Connected Papers Toggle Connected Papers ( What is Connected Papers? ) Litmaps Toggle Litmaps ( What is Litmaps? ) scite.ai Toggle scite Smart Citations ( What are Smart Citations? ) Code, Data, Media Code, Data and Media Associated with this Article alphaXiv Toggle alphaXiv ( What is alphaXiv? ) Links to Code Toggle CatalyzeX Code Finder for Papers ( What is CatalyzeX? ) DagsHub Toggle DagsHub ( What is DagsHub? ) GotitPub Toggle Gotit.pub ( What is GotitPub? ) Huggingface Toggle Hugging Face ( What is Huggingface? ) ScienceCast Toggle ScienceCast ( What is ScienceCast? ) Demos Demos Replicate Toggle Replicate ( What is Replicate? ) Spaces Toggle Hugging Face Spaces ( What is Spaces? ) Spaces Toggle TXYZ.AI ( What is TXYZ.AI? ) Related Papers Recommenders and Search Tools Link to Influence Flower Influence Flower ( What are Influence Flowers? ) Core recommender toggle CORE Recommender ( What is CORE? ) IArxiv recommender toggle IArxiv Recommender ( What is IArxiv? ) Author Venue Institution Topic About arXivLabs arXivLabs: experimental projects with community collaborators arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website. 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