Causal Discovery in Astrophysics: Unraveling Supermassive Black Hole and Galaxy Coevolution

Abstract

Correlation does not imply causation, but patterns of statistical association between variables can be exploited to infer a causal structure (even with purely observational data) with the burgeoning field of causal discovery. As a purely observational science, astrophysics has much to gain by exploiting these new methods. The supermassive black hole (SMBH)--galaxy interaction has long been constrained by observed scaling relations, that is low-scatter correlations between variables such as SMBH mass and the central velocity dispersion of stars in a host galaxy's bulge. This study, using advanced causal discovery techniques and an up-to-date dataset, reveals a causal link between galaxy properties and dynamically-measured SMBH masses. We apply a score-based Bayesian framework to compute the exact conditional probabilities of every causal structure that could possibly describe our galaxy sample. With the exact posterior distribution, we determine the most likely causal structures and notice a probable causal reversal when separating galaxies by morphology. In elliptical galaxies, bulge properties (built from major mergers) tend to influence SMBH growth, while in spiral galaxies, SMBHs are seen to affect host galaxy properties, potentially through feedback in gas-rich environments. For spiral galaxies, SMBHs progressively quench star formation, whereas in elliptical galaxies, quenching is complete, and the causal connection has reversed. Our findings support theoretical models of hierarchical assembly of galaxies and active galactic nuclei feedback regulating galaxy evolution. Our study suggests the potentiality for further exploration of causal links in astrophysical and cosmological scaling relations, as well as any other observational science.

35 pages, 21 figures, accepted by The Astrophysical Journal. Previously entitled "A Data-driven Discovery of the Causal Connection between Galaxy and Black Hole Evolution" in earlier versions

References in corpus (33)

• Array Programming with NumPy
• A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: I. Galaxy Mergers & Quasar Activity
• The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations
• The Co-Evolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe
• HyperLEDA. III. The catalogue of extragalactic distances
• Direct cosmological simulations of the growth of black holes and galaxies
• A Comprehensive Study on Galaxies at z~9-16 Found in the Early JWST Data: UV Luminosity Functions and Cosmic Star-Formation History at the Pre-Reionization Epoch
• A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: II. Formation of Red Ellipticals
• A CEERS Discovery of an Accreting Supermassive Black Hole 570 Myr after the Big Bang: Identifying a Progenitor of Massive z > 6 Quasars
• A definitive merger-AGN connection at z~0 with CFIS: mergers have an excess of AGN and AGN hosts are more frequently disturbed
• Black Hole Mass Scaling Relations for Early-Type Galaxies: $M_{BH}$-$M_{\ast ,sph}$ and $M_{BH}$-$M_{\ast ,gal}$
• The quenching of galaxies, bulges, and disks since cosmic noon: A machine learning approach for identifying causality in astronomical data
• On the cosmic evolution of AGN obscuration and the X-ray luminosity function: XMM-Newton and Chandra spectral analysis of the 31.3 deg${}^2$ Stripe 82X
• Appreciating mergers for understanding the non-linear $M_{\mathrm{bh}}$-$M_{\ast ,\mathrm{spheroid}}$ and $M_{\mathrm{bh}}$-$M_{\ast ,\mathrm{galaxy}}$ relations, updated herein, and the implications for the (reduced) role of AGN feedback
• The New Galaxy Evolution Paradigm Revealed by the Herschel Surveys
• A galaxy classification grid that better recognises early-type galaxy morphology
• The Contribution of In-situ and Ex-situ Star Formation in Early-Type Galaxies: MaNGA versus IllustrisTNG
• Defining the (Black Hole)-Spheroid Connection with the Discovery of Morphology-Dependent Substructure in the $M_{\mathrm{BH}}$--${\mathrm{n}}_{\mathrm{sph}}$ and $M_{\mathrm{BH}}$--${\mathrm{R}}_{\mathrm{e},\mathrm{sph}}$ Diagrams: New Tests for Advanced Theories and Realistic Simulations
• Disruption of Hierarchical Clustering in the Vela OB2 Complex and the Cluster Pair Collinder 135 and UBC7 with Gaia EDR3: Evidence of Supernova Quenching
• Inward Bound: The incredible journey of massive black holes as they pair and merge; I. The effect of mass ratio in flattened rotating galactic nuclei
• AGN X-ray luminosity function and absorption function in the Early Universe ($3\le z\le 6$)
• Reading the tea leaves in the $M_{\mathrm{bh}}$-$M_{\ast ,\mathrm{sph}}$ and $M_{\mathrm{bh}}$-$R_{\mathrm{e},\mathrm{sph}}$ diagrams: dry and gaseous mergers with remnant angular momentum
• Resequencing the Hubble sequence and the quadratic (black hole mass)-(spheroid stellar mass) relation for elliptical galaxies
• Invoking the virial theorem to understand the impact of (dry) mergers on the $M_{\mathrm{bh}}$-$\sigma$ relation
• Quashing a suspected selection bias in galaxy samples having dynamically-measured supermassive black holes
• Splitting the lentils: Clues to galaxy/black hole coevolution from the discovery of offset relations for non-dusty versus dusty (wet-merger-built) lenticular galaxies in the $M_{\mathrm{bh}}$-$M_{\ast ,\mathrm{spheroid}}$ diagram
• Discovery of a Planar Black Hole Mass Scaling Relation for Spiral Galaxies
• Understanding the Fundamental Plane and the Tully Fisher Relation
• Co-Evolution vs. Co-existence: The Effect of Accretion Modelling on the Evolution of Black Holes and Host Galaxies
• HELLO project: High-$z$ Evolution of Large and Luminous Objects
• Black Hole Scaling Relations in the Dwarf-galaxy Regime with $Gaia$-Sausage/Enceladus and $\omega$Centauri
• Relating the thermodynamic arrow of time to the causal arrow
• Elliptical (E) and ellicular (ES) galaxies in the M_bh-M_*,sph diagram, and a merger-driven explanation for the origin of ES galaxies, anti-truncated stellar discs in lenticular galaxies, and the Sersicification of E galaxy light profiles

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