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A post-merger enhancement only in star-forming Type 2 Seyfert galaxies: the deep learning view

Journal Article · · Monthly Notices of the Royal Astronomical Society
ABSTRACT

Supermassive black holes require a reservoir of cold gas at the centre of their host galaxy in order to accrete and shine as active galactic nuclei (AGN). Major mergers have the ability to drive gas rapidly inwards, but observations trying to link mergers with AGN have found mixed results due to the difficulty of consistently identifying galaxy mergers in surveys. This study applies deep learning to this problem, using convolutional neural networks trained to identify simulated post-merger galaxies from survey-realistic imaging. This provides a fast and repeatable alternative to human visual inspection. Using this tool, we examine a sample of ∼8500 Seyfert 2 galaxies ($$L[\mathrm{O\, {\small III}}] \sim 10^{38.5 - 42}$$ erg s−1) at z < 0.3 in the Sloan Digital Sky Survey and find a merger fraction of $$2.19_{-0.17}^{+0.21}$$ per cent compared with inactive control galaxies, in which we find a merger fraction of $$2.96_{-0.20}^{+0.26}$$ per cent, indicating an overall lack of mergers among AGN hosts compared with controls. However, matching the controls to the AGN hosts in stellar mass and star formation rate reveals that AGN hosts in the star-forming blue cloud exhibit a ∼2 × merger enhancement over controls, while those in the quiescent red sequence have significantly lower relative merger fractions, leading to the observed overall deficit due to the differing M*–SFR distributions. We conclude that while mergers are not the dominant trigger of all low-luminosity, obscured AGN activity in the nearby Universe, they are more important to AGN fuelling in galaxies with higher cold gas mass fractions as traced through star formation.

Sponsoring Organization:
USDOE
OSTI ID:
2310995
Journal Information:
Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 4 Vol. 528; ISSN 0035-8711
Publisher:
Oxford University PressCopyright Statement
Country of Publication:
United Kingdom
Language:
English

References (113)

DeepMerge: Classifying high-redshift merging galaxies with deep neural networks journal July 2020
What drives the growth of black holes? journal June 2012
The Dawes Review 10: The impact of deep learning for the analysis of galaxy surveys journal January 2023
Bars within bars: a mechanism for fuelling active galactic nuclei journal March 1989
Energy input from quasars regulates the growth and activity of black holes and their host galaxies journal February 2005
Stellar masses and star formation histories for 10 5 galaxies from the Sloan Digital Sky Survey journal May 2003
Black holes in pseudobulges: demography and models journal March 2012
Astropy: A community Python package for astronomy journal September 2013
Triggering active galactic nuclei in hierarchical galaxy formation: disk instability vs. interactions journal September 2014
Planck 2015 results : XIII. Cosmological parameters journal September 2016
Identifying galaxy mergers in observations and simulations with deep learning journal June 2019
Towards a consistent framework of comparing galaxy mergers in observations and simulations journal December 2020
A robust morphological classification of high-redshift galaxies using support vector machines on seeing limited images: I. Method description journal November 2007
On the Estimation of Confidence Intervals for Binomial Population Proportions in Astronomy: The Simplicity and Superiority of the Bayesian Approach journal January 2011
Classification parameters for the emission-line spectra of extragalactic objects journal February 1981
Extragalactic nebulae. journal October 1926
Ultraluminous infrared galaxies and the origin of quasars journal February 1988
The Sloan Digital Sky Survey Photometric Camera journal December 1998
Theoretical Modeling of Starburst Galaxies journal July 2001
The Relationship between Stellar Light Distributions of Galaxies and Their Formation Histories journal July 2003
Black Holes, Galaxy Formation, and the M BH - Relation journal September 2003
COSMOS Morphological Classification with the Zurich Estimator of Structural Types (ZEST) and the Evolution Since z = 1 of the Luminosity Function of Early, Disk, and Irregular Galaxies journal September 2007
UV Star Formation Rates in the Local Universe journal December 2007
The Evolution of Galaxy Mergers and Morphology at z < 1.2 in the Extended Groth Strip journal January 2008
Evidence for Quasar Activity Triggered by Galaxy Mergers in HST Observations of Dust‐reddened Quasars journal February 2008
A Cosmological Framework for the Co‐evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies. I. Galaxy Mergers and Quasar Activity journal April 2008
Direct Cosmological Simulations of the Growth of Black Holes and Galaxies journal March 2008
A Characteristic Division Between the Fueling of Quasars and Seyferts: five Simple Tests journal March 2009
The Propagation of Uncertainties in Stellar Population Synthesis Modeling. i. the Relevance of Uncertain Aspects of Stellar Evolution and the Initial mass Function to the Derived Physical Properties of Galaxies journal June 2009
Galaxy zoo: the Fundamentally Different Co-Evolution of Supermassive Black Holes and Their Early- and Late-Type host Galaxies journal February 2010
The Propagation of Uncertainties in Stellar Population Synthesis Modeling. iii. Model Calibration, Comparison, and Evaluation journal March 2010
THE BULK OF THE BLACK HOLE GROWTH SINCE z ∼ 1 OCCURS IN A SECULAR UNIVERSE: NO MAJOR MERGER-AGN CONNECTION journal December 2010
CANDELS: CONSTRAINING THE AGN-MERGER CONNECTION WITH HOST MORPHOLOGIES AT z ∼ 2 journal December 2011
Primus: the Dependence of agn Accretion on host Stellar mass and Color journal January 2012
A tale of two Populations: the Contribution of Merger and Secular Processes to the Evolution of Active Galactic Nuclei journal May 2012
MAJOR MERGERS HOST THE MOST-LUMINOUS RED QUASARS AT z ∼ 2: A HUBBLE SPACE TELESCOPE WFC3/IR STUDY journal June 2015
ARE COMPTON-THICK AGNs THE MISSING LINK BETWEEN MERGERS AND BLACK HOLE GROWTH? journal November 2015
The Seventh data Release of the Sloan Digital sky Survey journal May 2009
A Catalog of Bulge+Disk Decompositions and Updated Photometry for 1.12 Million Galaxies in the Sloan Digital sky Survey journal August 2011
A Catalog of Visual-Like Morphologies in the 5 Candels Fields Using deep Learning journal October 2015
The Driving Mechanism of Starbursts in Galaxy Mergers journal August 2010
DUST-CORRECTED COLORS REVEAL BIMODALITY IN THE HOST-GALAXY COLORS OF ACTIVE GALACTIC NUCLEI AT z ∼ 1 journal August 2010
Statistical Mechanics of Violent Relaxation in Stellar Systems journal May 1967
Galaxy morphology to I=25 mag in the Hubble Deep Field journal April 1996
Galaxy mergers in eagle do not induce a significant amount of black hole growth yet do increase the rate of luminous AGN journal April 2020
AstroVaDEr: astronomical variational deep embedder for unsupervised morphological classification of galaxies and synthetic image generation journal November 2020
A deep learning approach to test the small-scale galaxy morphology and its relationship with star formation activity in hydrodynamical simulations journal December 2020
Optimizing automatic morphological classification of galaxies with machine learning and deep learning using Dark Energy Survey imaging journal February 2020
DeepMerge – II. Building robust deep learning algorithms for merging galaxy identification across domains journal June 2021
Convolutional neural network identification of galaxy post-mergers in UNIONS using IllustrisTNG journal March 2021
Wet compaction to a blue nugget: a critical phase in galaxy evolution journal April 2023
Evidence for non-merger co-evolution of galaxies and their supermassive black holes journal June 2023
Galaxy interactions are the dominant trigger for local type 2 quasars journal February 2023
Wet disc contraction to galactic blue nuggets and quenching to red nuggets journal December 2013
Morphologies of z ∼ 0.7 AGN host galaxies in CANDELS: no trend of merger incidence with AGN luminosity journal February 2014
Do we expect most AGN to live in discs? journal September 2014
Triggering optical AGN: the need for cold gas, and the indirect roles of galaxy environment and interactions journal December 2014
Galaxy pairs in the Sloan Digital Sky Survey – IX. Merger-induced AGN activity as traced by the Wide-field Infrared Survey Explorer journal May 2014
On the dependence of galaxy morphologies on galaxy mergers journal June 2015
The merger rate of galaxies in the Illustris simulation: a comparison with observations and semi-empirical models journal March 2015
Compaction and quenching of high-z galaxies in cosmological simulations: blue and red nuggets journal May 2015
Simulating galaxy formation with black hole driven thermal and kinetic feedback journal November 2016
Host galaxies of luminous z  ∼ 0.6 quasars: major mergers are not prevalent at the highest AGN luminosities journal November 2016
Galaxies in the Illustris simulation as seen by the Sloan Digital Sky Survey - I: Bulge+disc decompositions, methods, and biases. journal January 2017
Simulating galaxy formation with the IllustrisTNG model journal October 2017
Galaxies in the Illustris simulation as seen by the Sloan Digital Sky Survey – II. Size–luminosity relations and the deficit of bulge-dominated galaxies in Illustris at low mass journal February 2017
First results from the IllustrisTNG simulations: the galaxy colour bimodality journal November 2017
First results from the IllustrisTNG simulations: the stellar mass content of groups and clusters of galaxies journal December 2017
First results from the IllustrisTNG simulations: matter and galaxy clustering journal December 2017
The power of infrared AGN selection in mergers: a theoretical study journal May 2018
First results from the IllustrisTNG simulations: radio haloes and magnetic fields journal August 2018
Cosmological simulations of black hole growth II: how (in)significant are merger events for fuelling nuclear activity? journal August 2018
The host galaxies of FeLoBAL quasars atz∼ 0.9 are not dominated by recent major mergers journal November 2018
Improving galaxy morphologies for SDSS with Deep Learning journal February 2018
First results from the IllustrisTNG simulations: a tale of two elements – chemical evolution of magnesium and europium journal March 2018
A definitive merger-AGN connection at z ∼ 0 with CFIS: mergers have an excess of AGN and AGN hosts are more frequently disturbed journal May 2019
The Hubble Sequence at z ∼ 0 in the IllustrisTNG simulation with deep learning journal August 2019
Secularly powered outflows from AGNs: the dominance of non-merger driven supermassive black hole growth journal September 2019
Deep learning predictions of galaxy merger stage and the importance of observational realism journal October 2019
Bulge plus disc and Sérsic decomposition catalogues for 16 908 galaxies in the SDSS Stripe 82 co-adds: a detailed study of the ugriz structural measurements journal March 2019
ALMA andHerschelreveal that X-ray-selected AGN and main-sequence galaxies have different star formation rate distributions journal August 2015
The host galaxies of active galactic nuclei journal December 2003
The physical properties of star-forming galaxies in the low-redshift Universe journal July 2004
Modelling feedback from stars and black holes in galaxy mergers journal August 2005
The effect of galaxy mass ratio on merger-driven starbursts journal February 2008
Modelling the cosmological co-evolution of supermassive black holes and galaxies – I. BH scaling relations and the AGN luminosity function journal April 2008
Galaxy Zoo: morphologies derived from visual inspection of galaxies from the Sloan Digital Sky Survey journal September 2008
A semi-analytic model for the co-evolution of galaxies, black holes and active galactic nuclei journal December 2008
Modelling the cosmological co-evolution of supermassive black holes and galaxies - II. The clustering of quasars and their dark environment journal June 2009
Galaxy Zoo: the fraction of merging galaxies in the SDSS and their morphologies journal January 2010
The optical morphologies of the 2 Jy sample of radio galaxies: evidence for galaxy interactions journal October 2010
Are luminous radio-loud active galactic nuclei triggered by galaxy interactions? journal October 2011
Triggering of merger-induced starbursts by the tidal field of galaxy groups and clusters journal March 2008
Cosmic Star-Formation History journal August 2014
Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies journal August 2013
The IllustrisTNG simulations: public data release journal May 2019
DO THE MOST MASSIVE BLACK HOLES AT z = 2 GROW VIA MAJOR MERGERS? journal October 2016
The Astropy Project: Building an Open-science Project and Status of the v2.0 Core Package journal August 2018
Evidence for Merger-driven Growth in Luminous, High- z , Obscured AGNs in the CANDELS/COSMOS Field journal January 2018
The Dramatic Size and Kinematic Evolution of Massive Early-type Galaxies journal April 2018
LSST: From Science Drivers to Reference Design and Anticipated Data Products journal March 2019
Major Mergers Are Not the Dominant Trigger for High-accretion AGNs at z ∼ 2 journal September 2019
A Significant Excess in Major Merger Rate for AGNs with the Highest Eddington Ratios at z < 0.2 journal November 2020
Cosmological Simulations of Quasar Fueling to Subparsec Scales Using Lagrangian Hyper-refinement journal August 2021
The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package* journal August 2022
Identifying Galaxy Mergers in Simulated CEERS NIRCam Images Using Random Forests journal January 2023
Measuring galaxy morphology at $z>1$. I - calibration of automated proxies preprint January 2014
Adam: A Method for Stochastic Optimization preprint January 2014
Identifying Mergers Using Quantitative Morphologies in Zoom Simulations of High-Redshift Galaxies preprint January 2018
The Connection between Mergers and AGN Activity in Simulated and Observed Massive Galaxies text January 2021
A Deep Learning Approach for Characterizing Major Galaxy Mergers preprint January 2021
ERGO-ML -- Comparing IllustrisTNG and HSC galaxy images via contrastive learning preprint January 2023
Quasars and Galaxy Formation text January 1998

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