Periodic Reporting for period 1 - BiD4BEST (Big Data applications for Black hole Evolution STudies)
Reporting period: 2020-03-01 to 2022-02-28
The overall objective is training doctoral researchers in one of the most crucial open question in astrophysics, formation of supermassive black holes and their impact on the evolution of galaxies. This study is structured as four distinct scientific Work Packages with ambitions that these researchers will acquire outstanding academic expertise, a solid theoretical framework and mastered state-of-the-art data-science tools in machine/deep learning and statistical analysis.
WP1-INFANCY The early black hole growth in highly starforming, dust-enshrouded galaxies
WP2-ADOLESCENCE Feedback and Outflows, The effects of AGN on their host galaxies
WP3-ADULTHOOD Galaxy properties and AGN
WP4-Bridging theoretical models to key observables
The importance is ensuring the creation in Europe of a critical mass of experts in supermassive black hole physics with excellent comprehensive scientific, computational, mathematical, statistical and soft skills, establishing a network with no precedent in Europe between world-leading modellers and observers promising a major progress in the field of supermassive black hole evolution.
WP1-INFANCY The early black hole growth in highly starforming, dust-enshrouded galaxies
WP2-ADOLESCENCE Feedback and Outflows, The effects of AGN on their host galaxies
WP3-ADULTHOOD Galaxy properties and AGN
WP4-Bridging theoretical models to key observables
The importance is ensuring the creation in Europe of a critical mass of experts in supermassive black hole physics with excellent comprehensive scientific, computational, mathematical, statistical and soft skills, establishing a network with no precedent in Europe between world-leading modellers and observers promising a major progress in the field of supermassive black hole evolution.
Main results
WP1: The aim of this WP is to probe the first phases of growth of SMBHs which are believed to occur in the early, dust-enshrouded growth phases of the host galaxies. To this purpose, we have catalogued significant samples of AGN from IR/radio/X-ray at different redshifts, with some of them specifically selected to be dust-enshrouded quasars, in their early growth phase, the so-called “red quasars”. We have then adopted a Bayesian-based multi-wavelength methodology to characterize the level of obscuration in deep Chandra COSMOS-legacy field data. We found that the obscured quasars have both higher star-formation IR luminosity and excess radio emission when compared to unobscured quasars. We also found an overall fraction of obscured AGN which is steadily decreasing with cosmic time, from ~60% at z~3, to ~20% in the local Universe.
WP2: The main goal is to probe the phase in which the SMBH is mature enough to eject energetic winds and jets with a potential to impact the host galaxy. This process is dubbed “AGN feedback”. We started by analysing the incidence of AGN feedback features in multiwavelength AGN samples, then moving to assessing the energetics associated with AGN outflows. To this purpose, we have selected ~1200 candidates AGN in the feedback phase out of a parent sample of ~14500 AGN at z>0.5. This is the largest sample available to date for this class of objects from a single X-ray survey field. We performed a parametric analysis of the [OIII] emission lines with the aim of searching for outflows and studied the outflow properties. We are also analysing Type-2 quasars in the nearby Universe along with the MEGARA datacubes to characterise the emission line kinematics. So far, we found that the kinetic power represents 0.1% of the quasar bolometric luminosity.
WP3: The main goal is to probe the connection between fully grown SMBHs and their host galaxies and large-scale environments, to shed light on the triggering mechanisms of AGN. For example, are AGN triggered in mergers and/or disc instabilities and/or fly-bys? Or something else? To this purpose, we developed aimed CNNs to detect mergers on realistic images of galaxy mergers extracted from the cosmological Illustris TNG simulation. Our CNNs show a very good ability to identify mergers in realistic SDSS-like images. The realism and methodology of our ML-based approach can be applied to different datasets. We derived from miniJPAS a power-law Eddington ratio distribution for AGN down to one percent Eddington, consistent with what inferred from X-ray surveys. The properties of different galaxy components, for both AGN and non-AGN, are then derived with the SED-fitting code X-CIGALE and are currently being analysed. We built a semi-empirical model of AGN, from state-of-the-art X-ray-based specific accretion rate distributions consistent with our observations from miniJPAS, to predict the AGN fraction as a function of redshift and environment.
WP4: The main goal is to provide a robust theoretical background to all observational projects developed in WP1-3, using phenomenological/data-driven models, semi-analytic models, and hydrodynamic simulations. Starting from the growth of massive “seed” BHs in high-redshift, dust-enshrouded galaxies, we built a full-scale BH mass function, from stellar mass BHs to supermassive BHs at different cosmic epochs. We have included state-of-the-art subgrid models of BH growth and feedback from supernovae and AGN in the COLBRE hydrodynamic simulations, which will allow us to investigate the effects of the AGN feedback in galaxies in detail and for a large sample of galaxies. Furthermore, we have developed a cutting-edge SMBH spin evolution model which will be coupled to a prescription for energy injection aimed at reproducing the interaction of jets from AGN with the surrounding medium. We developed DREAM, a new DiscRete statistical sEmi-empiricAl Model specifically designed to predict rapidly and efficiently, in a full ΛCDM cosmological context, galaxy assembly and merger histories for any given input stellar mass-halo mass relation. We have applied it to study bulge formation, and currently to predict SMBH mergers and assembly. We are developing both analytic continuity equation models to study the growth of SMBHs from stellar seed to their final supermassive stages and built a full BH mass function. In addition, we are predicting in semi-analytic and semi-empirical models the roles of both evolutionary and orientation models in shaping obscuration in AGN. So far, we find that a central torus component seems to be a key component in all Compton-thick sources at any stage of their evolution.
WP1: The aim of this WP is to probe the first phases of growth of SMBHs which are believed to occur in the early, dust-enshrouded growth phases of the host galaxies. To this purpose, we have catalogued significant samples of AGN from IR/radio/X-ray at different redshifts, with some of them specifically selected to be dust-enshrouded quasars, in their early growth phase, the so-called “red quasars”. We have then adopted a Bayesian-based multi-wavelength methodology to characterize the level of obscuration in deep Chandra COSMOS-legacy field data. We found that the obscured quasars have both higher star-formation IR luminosity and excess radio emission when compared to unobscured quasars. We also found an overall fraction of obscured AGN which is steadily decreasing with cosmic time, from ~60% at z~3, to ~20% in the local Universe.
WP2: The main goal is to probe the phase in which the SMBH is mature enough to eject energetic winds and jets with a potential to impact the host galaxy. This process is dubbed “AGN feedback”. We started by analysing the incidence of AGN feedback features in multiwavelength AGN samples, then moving to assessing the energetics associated with AGN outflows. To this purpose, we have selected ~1200 candidates AGN in the feedback phase out of a parent sample of ~14500 AGN at z>0.5. This is the largest sample available to date for this class of objects from a single X-ray survey field. We performed a parametric analysis of the [OIII] emission lines with the aim of searching for outflows and studied the outflow properties. We are also analysing Type-2 quasars in the nearby Universe along with the MEGARA datacubes to characterise the emission line kinematics. So far, we found that the kinetic power represents 0.1% of the quasar bolometric luminosity.
WP3: The main goal is to probe the connection between fully grown SMBHs and their host galaxies and large-scale environments, to shed light on the triggering mechanisms of AGN. For example, are AGN triggered in mergers and/or disc instabilities and/or fly-bys? Or something else? To this purpose, we developed aimed CNNs to detect mergers on realistic images of galaxy mergers extracted from the cosmological Illustris TNG simulation. Our CNNs show a very good ability to identify mergers in realistic SDSS-like images. The realism and methodology of our ML-based approach can be applied to different datasets. We derived from miniJPAS a power-law Eddington ratio distribution for AGN down to one percent Eddington, consistent with what inferred from X-ray surveys. The properties of different galaxy components, for both AGN and non-AGN, are then derived with the SED-fitting code X-CIGALE and are currently being analysed. We built a semi-empirical model of AGN, from state-of-the-art X-ray-based specific accretion rate distributions consistent with our observations from miniJPAS, to predict the AGN fraction as a function of redshift and environment.
WP4: The main goal is to provide a robust theoretical background to all observational projects developed in WP1-3, using phenomenological/data-driven models, semi-analytic models, and hydrodynamic simulations. Starting from the growth of massive “seed” BHs in high-redshift, dust-enshrouded galaxies, we built a full-scale BH mass function, from stellar mass BHs to supermassive BHs at different cosmic epochs. We have included state-of-the-art subgrid models of BH growth and feedback from supernovae and AGN in the COLBRE hydrodynamic simulations, which will allow us to investigate the effects of the AGN feedback in galaxies in detail and for a large sample of galaxies. Furthermore, we have developed a cutting-edge SMBH spin evolution model which will be coupled to a prescription for energy injection aimed at reproducing the interaction of jets from AGN with the surrounding medium. We developed DREAM, a new DiscRete statistical sEmi-empiricAl Model specifically designed to predict rapidly and efficiently, in a full ΛCDM cosmological context, galaxy assembly and merger histories for any given input stellar mass-halo mass relation. We have applied it to study bulge formation, and currently to predict SMBH mergers and assembly. We are developing both analytic continuity equation models to study the growth of SMBHs from stellar seed to their final supermassive stages and built a full BH mass function. In addition, we are predicting in semi-analytic and semi-empirical models the roles of both evolutionary and orientation models in shaping obscuration in AGN. So far, we find that a central torus component seems to be a key component in all Compton-thick sources at any stage of their evolution.
Summarised scientific results:
WP1: Our fitting templates algorithms and determination of redshift dependent AGN obscured fractions are of extreme relevance for observational determination of AGN in large surveys, and to constrain cosmological models of the co-evolution of black holes and galaxies.
WP2: We have developed sound strategies to measure mass outflow rates and energetics from observational data to be compared against model predictions.
WP3: We aim to soon be able to release/publish ad-hoc ML-based algorithms to determine the merger/morphology status on very large samples of active and inactive galaxies (e.g. LSST, Euclid). In addition, we will have very detailed measures of SMBH Eddington ratio distributions and host galaxy properties, that will be invaluable to constrain SMBH scaling relations and cosmological models.
WP4: Our new phenomenological method built around a new framework of continuity equation coupled to empirical galaxy properties, yields the BH mass function across the full mass spectrum. This result is extremely relevant for cosmological models, to provide sound constraints on the existence of massive BHs at high redshift, and to give constraints to the future LISA Gravitational Wave background signal. We have also set out a semi-empirical model DREAM, which allows to predict the mean stellar mass assembly and merging histories of galaxies of any given final mass for any input stellar mass-halo mass relation. We will also make available our hydrodynamic simulations and SMBH feeding and feedback recipes for others to compare with and/or implement in their models.
WP1: Our fitting templates algorithms and determination of redshift dependent AGN obscured fractions are of extreme relevance for observational determination of AGN in large surveys, and to constrain cosmological models of the co-evolution of black holes and galaxies.
WP2: We have developed sound strategies to measure mass outflow rates and energetics from observational data to be compared against model predictions.
WP3: We aim to soon be able to release/publish ad-hoc ML-based algorithms to determine the merger/morphology status on very large samples of active and inactive galaxies (e.g. LSST, Euclid). In addition, we will have very detailed measures of SMBH Eddington ratio distributions and host galaxy properties, that will be invaluable to constrain SMBH scaling relations and cosmological models.
WP4: Our new phenomenological method built around a new framework of continuity equation coupled to empirical galaxy properties, yields the BH mass function across the full mass spectrum. This result is extremely relevant for cosmological models, to provide sound constraints on the existence of massive BHs at high redshift, and to give constraints to the future LISA Gravitational Wave background signal. We have also set out a semi-empirical model DREAM, which allows to predict the mean stellar mass assembly and merging histories of galaxies of any given final mass for any input stellar mass-halo mass relation. We will also make available our hydrodynamic simulations and SMBH feeding and feedback recipes for others to compare with and/or implement in their models.