Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userRevealing the Origin and Cosmic Evolution of Supermassive Black Holes
89
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The next generation of electromagnetic and gravitational wave observatories will open unprecedented windows to the birth of the first supermassive black holes. This has the potential to reveal their origin and growth in the first billion years, as well as the signatures of their formation history in the local Universe. With this in mind, we outline three key focus areas which will shape research in the next decade and beyond: (1) What were the seeds of the first quasars; how did some reach a billion solar masses before z$sim7$? (2) How does black hole growth change over cosmic time, and how did the early growth of black holes shape their host galaxies? What can we learn from intermediate mass black holes (IMBHs) and dwarf galaxies today? (3) Can we unravel the physics of black hole accretion, understanding both inflows and outflows (jets and winds) in the context of the theory of general relativity? Is it valid to use these insights to scale between stellar and supermassive BHs, i.e., is black hole accretion really scale invariant? In the following, we identify opportunities for the Canadian astronomical community to play a leading role in addressing these issues, in particular by leveraging our strong involvement in the Event Horizon Telescope, the {it James Webb Space Telescope} (JWST), Euclid, the Maunakea Spectroscopic Explorer (MSE), the Thirty Meter Telescope (TMT), the Square Kilometer Array (SKA), the Cosmological Advanced Survey Telescope for Optical and ultraviolet Research (CASTOR), and more. We also discuss synergies with future space-based gravitational wave (LISA) and X-ray (e.g., Athena, Lynx) observatories, as well as the necessity for collaboration with the stellar and galactic evolution communities to build a complete picture of the birth of supermassive black holes, and their growth and their influence over the history of the Universe.
rate research
Read More
We summarize what large surveys of the contemporary universe have taught us about the physics and phenomenology of the processes that link the formation and evolution of galaxies and their central supermassive black holes. We present a picture in which the population of AGN can be divided into two distinct populations. The Radiative-Mode AGN are associated with black holes that produce radiant energy powered by accretion at rates in excess of ~1% of the Eddington Limit. They are primarily associated with less massive black holes growing in high-density pseudo-bulges at a rate sufficient to produce the total mass budget in these black holes in ~10 Gyr. The circum-nuclear environment contains high density cold gas and associated star-formation. Major mergers are not the primary mechanism for transporting this gas inward; secular processes appear dominant. Stellar feedback will be generic in these objects and strong AGN feedback is seen only in the most powerful AGN. In Jet-Mode AGN the bulk of energetic output takes the form of collimated outflows (jets). These AGN are associated with the more massive black holes in more massive (classical) bulges and elliptical galaxies. Neither the accretion onto these black holes nor star-formation in their host bulge is significant today. These AGN are probably fueled by the accretion of slowly cooling hot gas that is limited by the feedback/heating provided by AGN radio sources. Surveys of the high-redshift universe are painting a similar picture. (Abridged).
We analyse the demographics of black holes (BHs) in the large-volume cosmological hydrodynamical simulation Horizon-AGN. This simulation statistically models how much gas is accreted onto BHs, traces the energy deposited into their environment and, consequently, the back-reaction of the ambient medium on BH growth. The synthetic BHs reproduce a variety of observational constraints such as the redshift evolution of the BH mass density and the mass function. Strong self-regulation via AGN feedback, weak supernova feedback, and unresolved internal processes result in a tight BH-galaxy mass correlation. Starting at z~2, tidal stripping creates a small population of BHs over-massive with respect to the halo. The fraction of galaxies hosting a central BH or an AGN increases with stellar mass. The AGN fraction agrees better with multi-wavelength studies, than single-wavelength ones, unless obscuration is taken into account. The most massive halos present BH multiplicity, with additional BHs gained by ongoing or past mergers. In some cases, both a central and an off-centre AGN shine concurrently, producing a dual AGN. This dual AGN population dwindles with decreasing redshift, as found in observations. Specific accretion rate and Eddington ratio distributions are in good agreement with observational estimates. The BH population is dominated in turn by fast, slow, and very slow accretors, with transitions occurring at z=3 and z=2 respectively.
We carry out a comprehensive Bayesian correlation analysis between hot halos and direct masses of supermassive black holes (SMBHs), by retrieving the X-ray plasma properties (temperature, luminosity, density, pressure, masses) over galactic to cluster scales for 85 diverse systems. We find new key scalings, with the tightest relation being the $M_bullet-T_{rm x}$, followed by $M_bullet-L_{rm x}$. The tighter scatter (down to 0.2 dex) and stronger correlation coefficient of all the X-ray halo scalings compared with the optical counterparts (as the $M_bullet-sigma_{rm e}$) suggest that plasma halos play a more central role than stars in tracing and growing SMBHs (especially those that are ultramassive). Moreover, $M_bullet$ correlates better with the gas mass than dark matter mass. We show the important role of the environment, morphology, and relic galaxies/coronae, as well as the main departures from virialization/self-similarity via the optical/X-ray fundamental planes. We test the three major channels for SMBH growth: hot/Bondi-like models have inconsistent anti-correlation with X-ray halos and too low feeding; cosmological simulations find SMBH mergers as sub-dominant over most of the cosmic time and too rare to induce a central-limit-theorem effect; the scalings are consistent with chaotic cold accretion (CCA), the rain of matter condensing out of the turbulent X-ray halos that sustains a long-term self-regulated feedback loop. The new correlations are major observational constraints for models of SMBH feeding/feedback in galaxies, groups, and clusters (e.g., to test cosmological hydrodynamical simulations), and enable the study of SMBHs not only through X-rays, but also via the Sunyaev-Zeldovich effect (Compton parameter), lensing (total masses), and cosmology (gas fractions).
We investigate the evolution of supermassive binary black holes (BBHs) in galaxies with realistic property distributions and the gravitational-wave (GW) radiation from the cosmic population of these BBHs. We incorporate a comprehensive treatment of the dynamical interactions of the BBHs with their environments by including the effects of galaxy triaxial shapes and inner stellar distributions, and generate a large number of BBH evolution tracks. By combining these BBH evolution tracks, galaxy mass functions, galaxy merger rates, and supermassive black hole-host galaxy relations into our model, we obtain the statistical distributions of surviving BBHs, BBH coalescence rates, the strength of their GW radiation, and the stochastic GW background (GWB) contributed by the cosmic BBH population. About ~1%-3% (or ~10%) of supermassive BHs at nearby galactic centers are expected to be binaries with mass ratio >1/3 (or >1/100). The characteristic strain amplitude of the GWB at frequency 1/yr is estimated to be ~$2.0^{+1.4}_{-0.8}times 10^{-16}$, and the upper bound of its results obtained with the different BH-host galaxy relations can be up to $5.4times 10^{-16}$, which await testing by future experiments (e.g., the Square Kilometer Array, FAST, Next-Generation Very Large Array). The turnover frequency of the GWB spectrum is at ~0.25nHz. The uncertainties on the above estimates and prospects for detecting individual sources are also discussed. The application of the cosmic BBH population to the Laser Interferometer Space Antenna (LISA) band provides a lower limit to the detection rate of BBHs by LISA, ~0.9/yr.
In this white paper we explore the capabilities required to identify and study supermassive black holes formed from heavy seeds ($mathrm{M_{bullet}} sim 10^4 - 10^6 , mathrm{M_{odot}}$) in the early Universe. To obtain an unequivocal detection of heavy seeds we need to probe mass scales of $sim 10^{5-6} , mathrm{M_{odot}}$ at redshift $z gtrsim 10$. From this theoretical perspective, we review the observational requirements and how they compare with planned/proposed instruments, in the infrared, X-ray and gravitational waves realms. In conclusion, detecting heavy black hole seeds at $z gtrsim 10$ in the next decade will be challenging but, according to current theoretical models, feasible with upcoming/proposed facilities. Their detection will be fundamental to understand the early history of the Universe, as well as its evolution until now. Shedding light on the dawn of black holes will certainly be one of the key tasks that the astronomical community will focus on in the next decade.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
