scholarly journals The mass assembly of high-redshift black holes

2020 ◽  
Vol 500 (2) ◽  
pp. 2146-2158
Author(s):  
Olmo Piana ◽  
Pratika Dayal ◽  
Marta Volonteri ◽  
Tirthankar Roy Choudhury

ABSTRACT We use the Delphi semi-analytic model to study the mass assembly and properties of high-redshift (z > 4) black holes over a wide mass range, $10^3 \lt M_{\rm bh}/{\rm \rm M_\odot }\lt 10^{10}$. Our black hole growth implementation includes a critical halo mass ($M_{\mathrm{ h}}^{\mathrm{ crit}}$) below which the black hole is starved and above which it is allowed to grow either at the Eddington limit or proportionally to the gas content of the galaxy. As a consequence, after an initial growth phase dominated by black hole mergers down to z ∼ 7 (9), supermassive black holes in z = 4 halo masses of $M_\mathrm{ h}|_{z=4} \sim 10^{11.75} \, (10^{13.4}) \, {\rm \rm M_\odot }$ mainly grow by gas accretion from the interstellar medium. In particular, we find that (i) while most of the accretion occurs in the major branch for $M_\mathrm{ h}|_{z=4} \sim 10^{11\!-\!12} \, {\rm \rm M_\odot }$ haloes, accretion in secondary branches plays a significant role in assembling the black hole mass in higher mass haloes ($M_\mathrm{ h}|_{z=4} \gtrsim 10^{12} \, {\rm \rm M_\odot }$); (ii) while the Eddington ratio increases with decreasing redshift for low-mass ($M_{\mathrm{ bh}} \lt 10^5 \, {\rm \rm M_\odot }$) black holes, it shows the opposite trend for larger masses. In addition, since the accretion rate depends on the gas mass present in the host halo, the duty cycle of the Eddington-limited accretion phase – which can last up to ≈650 Myr – is crucially linked to the joint assembly history of the black hole and its host halo.

2019 ◽  
Vol 489 (1) ◽  
pp. 1006-1022 ◽  
Author(s):  
Angelo Ricarte ◽  
Fabio Pacucci ◽  
Nico Cappelluti ◽  
Priyamvada Natarajan

ABSTRACT There exist hitherto unexplained fluctuations in the cosmic infrared background on arcminute scales and larger. These have been shown to cross-correlate with the cosmic X-ray background, leading several authors to attribute the excess to a high-redshift growing black hole population. In order to investigate potential sources that could explain this excess, in this paper, we develop a new framework to compute the power spectrum of undetected sources that do not have constant flux as a function of halo mass. In this formulation, we combine a semi-analytic model for black hole growth and their simulated spectra from hydrodynamical simulations. Revisiting the possible contribution of a high-redshift black hole population, we find that too much black hole growth is required at early epochs for z > 6 accretion to explain these fluctuations. Examining a population of accreting black holes at more moderate redshifts, z ∼ 2–3, we find that such models produce a poor fit to the observed fluctuations while simultaneously overproducing the local black hole mass density. Additionally, we rule out the hypothesis of a missing Galactic foreground of warm dust that produces coherent fluctuations in the X-ray via reflection of Galactic X-ray binary emission. Although we firmly rule out accreting massive black holes as the source of these missing fluctuations, additional studies will be required to determine their origin.


2019 ◽  
Vol 621 ◽  
pp. L1 ◽  
Author(s):  
Zacharias Roupas ◽  
Demosthenes Kazanas

We show that binaries of stellar-mass black holes formed inside a young protoglobular cluster, can grow rapidly inside the cluster’s core by accretion of the intracluster gas, before the gas may be depleted from the core. A black hole with mass of the order of eight solar masses can grow to values of the order of thirty five solar masses in accordance with recent gravitational waves signals observed by LIGO. Due to the black hole mass increase, a binary may also harden. The growth of binary black holes in a dense protoglobular cluster through mass accretion indicates a potentially important formation and hardening channel.


Author(s):  
Philippa S Cole ◽  
Joseph Silk

Abstract Primordial black hole production in the mass range 10 − 104 M⊙ is motivated respectively by interpretations of the LIGO/Virgo observations of binary black hole mergers and by their ability to seed intermediate black holes which would account for the presence of supermassive black holes at very high redshift. Their existence would imply a boost in the primordial power spectrum if they were produced by overdensities reentering the horizon and collapsing after single-field inflation. This, together with their associated Poisson fluctuations would cause a boost in the matter power spectrum on small scales. The extra power could become potentially observable in the 21cm power spectrum on scales around k ∼ 0.1 − 50 Mpc−1 with the new generation of filled low frequency interferometers. We explicitly include the contribution from primordial fluctuations in our prediction of the 21cm signal which has been previously neglected, by constructing primordial power spectra motivated by single-field models of inflation that would produce extra power on small scales. We find that depending on the mass and abundance of primordial black holes, it is important to include this contribution from the primordial fluctuations, so as not to underestimate the 21cm signal. Evidently our predictions of detectability, which lack any modelling of foregrounds, are unrealistic, but we hope that they will motivate improved cleaning algorithms that can enable us to access this intriguing corner of PBH-motivated parameter space.


2019 ◽  
Vol 630 ◽  
pp. A144 ◽  
Author(s):  
L. Bassini ◽  
E. Rasia ◽  
S. Borgani ◽  
C. Ragone-Figueroa ◽  
V. Biffi ◽  
...  

Context. The correlations between the properties of the brightest cluster galaxy (BCG) and the mass of its central super-massive black hole (SMBH) have been extensively studied from a theoretical and observational angle. More recently, relations connecting the SMBH mass and global properties of the hosting cluster, such as temperature and mass, were observed. Aims. We investigate the correlation between SMBH mass and cluster mass and temperature, their establishment and evolution. We compare their scatter to that of the classical MBH − MBCG relation. Moreover, we study how gas accretion and BH-BH mergers contribute to SMBH growth across cosmic time. Methods. We employed 135 groups and clusters with a mass range 1.4 × 1013 M⊙ − 2.5 × 1015 M⊙ extracted from a set of 29 zoom-in cosmological hydro-dynamical simulations where the baryonic physics is treated with various sub-grid models, including feedback by active galactic nuclei. Results. In our simulations we find that MBH correlates well with M500 and T500, with the scatter around these relations compatible within 2σ with the scatter around MBH − MBCG at z = 0. The MBH − M500 relation evolves with time, becoming shallower at lower redshift as a direct consequence of hierarchical structure formation. On average, in our simulations the contribution of gas accretion to the total SMBH mass dominates for the majority of the cosmic time (z >  0.4), while in the last 2 Gyr the BH-BH mergers become a larger contributor. During this last process, substructures hosting SMBHs are disrupted in the merger process with the BCG and the unbound stars enrich the diffuse stellar component rather than increase BCG mass. Conclusions. From the results obtained in our simulations with simple sub-grid models we conclude that the scatter around the MBH − T500 relation is comparable to the scatter around the MBH − MBCG relation and that, given the observational difficulties related to the estimation of the BCG mass, clusters temperature and mass can be a useful proxy for the SMBHs mass, especially at high redshift.


2020 ◽  
Vol 494 (2) ◽  
pp. 2747-2759 ◽  
Author(s):  
Madeline A Marshall ◽  
Simon J Mutch ◽  
Yuxiang Qin ◽  
Gregory B Poole ◽  
J Stuart B Wyithe

ABSTRACT Correlations between black holes and their host galaxies provide insight into what drives black hole–host co-evolution. We use the Meraxes semi-analytic model to investigate the growth of black holes and their host galaxies from high redshift to the present day. Our modelling finds no significant evolution in the black hole–bulge and black hole–total stellar mass relations out to a redshift of 8. The black hole–total stellar mass relation has similar but slightly larger scatter than the black hole–bulge relation, with the scatter in both decreasing with increasing redshift. In our modelling, the growth of galaxies, bulges, and black holes are all tightly related, even at the highest redshifts. We find that black hole growth is dominated by instability-driven or secular quasar-mode growth and not by merger-driven growth at all redshifts. Our model also predicts that disc-dominated galaxies lie on the black hole–total stellar mass relation, but lie offset from the black hole–bulge mass relation, in agreement with recent observations and hydrodynamical simulations.


Author(s):  
Arpan Das ◽  
Dominik R G Schleicher ◽  
Nathan W C Leigh ◽  
Tjarda C N Boekholt

Abstract More than two hundred supermassive black holes (SMBHs) of masses ≳ 109 M⊙ have been discovered at z ≳ 6. One promising pathway for the formation of SMBHs is through the collapse of supermassive stars (SMSs) with masses ∼103 − 5 M⊙ into seed black holes which could grow upto few times 109 M⊙ SMBHs observed at z ∼ 7. In this paper, we explore how SMSs with masses ∼103 − 5 M⊙ could be formed via gas accretion and runaway stellar collisions in high-redshift, metal-poor nuclear star clusters (NSCs) using idealised N-body simulations. We explore physically motivated accretion scenarios, e.g. Bondi-Hoyle-Lyttleton accretion and Eddington accretion, as well as simplified scenarios such as constant accretions. While gas is present, the accretion timescale remains considerably shorter than the timescale for collisions with the most massive object (MMO). However, overall the timescale for collisions between any two stars in the cluster can become comparable or shorter than the accretion timescale, hence collisions still play a crucial role in determining the final mass of the SMSs. We find that the problem is highly sensitive to the initial conditions and our assumed recipe for the accretion, due to the highly chaotic nature of the problem. The key variables that determine the mass growth mechanism are the mass of the MMO and the gas reservoir that is available for the accretion. Depending on different conditions, SMSs of masses ∼103 − 5 M⊙ can form for all three accretion scenarios considered in this work.


Author(s):  
Pavel Kroupa ◽  
Ladislav Subr ◽  
Tereza Jerabkova ◽  
Long Wang

Abstract The observation of quasars at very high redshift such as Pōniuā’ena is a challenge for models of super-massive black hole (SMBH) formation. This work presents a study of SMBH formation via known physical processes in star-burst clusters formed at the onset of the formation of their hosting galaxy. While at the early stages hyper-massive star-burst clusters reach the luminosities of quasars, once their massive stars die, the ensuing gas accretion from the still forming host galaxy compresses its stellar black hole (BH) component to a compact state overcoming heating from the BH–BH binaries such that the cluster collapses, forming a massive SMBH-seed within about a hundred Myr. Within this scenario the SMBH–spheroid correlation emerges near-to-exactly. The highest-redshift quasars may thus be hyper-massive star-burst clusters or young ultra-compact dwarf galaxies (UCDs), being the precursors of the SMBHs that form therein within about 200 Myr of the first stars. For spheroid masses ≲ 109.6 M⊙ a SMBH cannot form and instead only the accumulated nuclear cluster remains. The number evolution of the quasar phases with redshift is calculated and the possible problem of missing quasars at very high redshift is raised. SMBH-bearing UCDs and the formation of spheroids are discussed critically in view of the high redshift observations. A possible tension is found between the high star-formation rates (SFRs) implied by downsizing and the observed SFRs, which may be alleviated within the IGIMF theory and if the downsizing times are somewhat longer.


2019 ◽  
Vol 491 (2) ◽  
pp. 2939-2952 ◽  
Author(s):  
Benjamin D Oppenheimer ◽  
Jonathan J Davies ◽  
Robert A Crain ◽  
Nastasha A Wijers ◽  
Joop Schaye ◽  
...  

ABSTRACT Davies et al. established that for L* galaxies the fraction of baryons in the circumgalactic medium (CGM) is inversely correlated with the mass of their central supermassive black holes (BHs) in the EAGLE hydrodynamic simulation. The interpretation is that, over time, a more massive BH has provided more energy to transport baryons beyond the virial radius, which additionally reduces gas accretion and star formation. We continue this research by focusing on the relationship between the (1) BH masses (MBH), (2) physical and observational properties of the CGM, and (3) galaxy colours for Milky Way-mass systems. The ratio of the cumulative BH feedback energy over the gaseous halo binding energy is a strong predictor of the CGM gas content, with BHs injecting significantly higher than the binding energy resulting in gas-poor haloes. Observable tracers of the CGM, including $\rm {C\, \small{IV}}$, $\rm {O\, \small{VI}}$, and ${\rm {H\, \small{I}}}$ absorption line measurements, are found to be effective tracers of the total z ∼ 0 CGM halo mass. We use high-cadence simulation outputs to demonstrate that BH feedback pushes baryons beyond the virial radius within 100 Myr time-scales, but that CGM metal tracers take longer (0.5–2.5 Gyr) to respond. Secular evolution of galaxies results in blue, star-forming or red, passive populations depending on the cumulative feedback from BHs. The reddest quartile of galaxies with M* = 1010.2−10.7 M⊙ (median u − r = 2.28) has a CGM mass that is 2.5 times lower than the bluest quartile (u − r = 1.59). We propose observing strategies to indirectly ascertain fCGM via metal lines around galaxies with measured MBH. We predict statistically detectable declines in $\rm {C\, \small{IV}}$ and $\rm {O\, \small{VI}}$ covering fractions with increasing MBH for central galaxies with M* = 1010.2−10.7M⊙.


2020 ◽  
Vol 496 (1) ◽  
pp. L116-L121
Author(s):  
Yu Luo ◽  
Zongnan Li ◽  
Xi Kang ◽  
Zhiyuan Li ◽  
Peng Wang

ABSTRACT Quenched massive spiral galaxies have attracted great attention recently, as more data are available to constrain their environment and cold gas content. However, the quenching mechanism is still uncertain, as it depends on the mass range and baryon budget of the galaxy. In this letter, we report the identification of a rare population of very massive, quenched spiral galaxies with stellar mass ≳1011 M⊙ and halo mass ≳1013 M⊙ from the Sloan Digital Sky Survey at redshift z ∼ 0.1. Our CO observations using the IRAM (Institute for Radio Astronomy in the Millimeter Range) 30-m telescope show that these galaxies contain only a small amount of molecular gas. Similar galaxies are also seen in the state-of-the-art semi-analytical models and hydrodynamical simulations. It is found from these theoretical models that these quenched spiral galaxies harbour massive black holes, suggesting that feedback from the central black holes has quenched these spiral galaxies. This quenching mechanism seems to challenge the popular scenario of the co-evolution between massive black holes and massive bulges.


2009 ◽  
Vol 5 (S267) ◽  
pp. 263-263
Author(s):  
Brandon C. Kelly ◽  
Marianne Vestergaard ◽  
Xiaohui Fan ◽  
Lars Hernquist ◽  
Philip Hopkins ◽  
...  

We present the first estimate of the black hole mass function (BHMF) of broad-line quasars (BLQSOs) that self-consistently corrects for incompleteness and the statistical uncertainty in the mass estimates, based on a sample of 9886 quasars at 1 < z < 4.5 drawn from the Sloan Digital Sky Survey. We find evidence for “cosmic downsizing” of black holes in BLQSOs, where the peak in their number density shifts to higher redshift with increasing black hole mass. We estimate the lifetime of the BLQSO phase to be 70 ± 5 Myr for supermassive black holes (SMBHs) at z = 1 with a mass of MBH = 109M⊙, and we constrain the maximum mass of a black hole in a BLQSO to be ~ 1010M⊙. We find that most BLQSOs are not radiating at or near the Eddington limit. Our results are consistent with models for self-regulated black hole growth, where the BLQSO phase occurs at the end of a fueling event when black hole feedback unbinds the accreting gas.


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