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Register a new userA universal relation between the properties of supermassive black holes, galaxies, and dark matter halos
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We study the relations between the mass of the central black hole (BH) $M_{rm BH}$, the dark matter halo mass $M_{rm h}$, and the stellar-to-halo mass fraction $f_starpropto M_star/M_{rm h}$ in a sample of $55$ nearby galaxies with dynamically measured $M_{rm BH}>10^6,{rm M}_odot$ and $M_{rm h}>5times10^{11},{rm M}_odot$. The main improvement with respect to previous studies is that we consider both early- and late-type systems for which $M_{rm h}$ is determined either from globular cluster dynamics or from spatially resolved rotation curves. Independently of their structural properties, galaxies in our sample build a well defined sequence in the $M_{rm BH}$-$M_{rm h}$-$f_star$ space. We find that: (i) $M_{rm h}$ and $M_{rm BH}$ strongly correlate with each other and anti-correlate with $f_star$; (ii) there is a break in the slope of the $M_{rm BH}$-$M_{rm h}$ relation at $M_{rm h}$ of $10^{12},{rm M}_odot$, and in the $f_star$-$M_{rm BH}$ relation at $M_{rm BH}$ of $sim10^7!-!10^8,{rm M}_odot$; (iii) at a fixed $M_{rm BH}$, galaxies with a larger $f_star$ tend to occupy lighter halos and to have later morphological types. We show that the observed trends can be reproduced by a simple equilibrium model in the $Lambda$CDM framework where galaxies smoothly accrete dark and baryonic matter at a cosmological rate, having their stellar and black hole build-up regulated both by the cooling of the available gas reservoir and by the negative feedback from star formation and active galactic nuclei (AGN). Feature (ii) arises as the BH population transits from a rapidly accreting phase to a more gentle and self-regulated growth, while scatter in the AGN feedback efficiency can account for feature (iii).
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The possibility that the masses of supermassive black holes (SBHs) correlate with the total gravitational mass of their host galaxy, or the mass of the dark matter halo in which they presumably formed, is investigated using a sample of 16 spiral and 20 elliptical galaxies. The bulge velocity dispersion, typically defined within an aperture of size less than 0.5 kpc, is found to correlate tightly with the galaxys circular velocity, the latter measured at distances from the galactic center at which the rotation curve is flat, 20 to 80kpc. By using the well known M-sigma relation for SBHs, and a prescription to relate the circular velocity to the mass of the dark matter halo in a standard CDM cosmology, the correlation between velocity dispersion and circular velocity is equivalent to one between SBH and halo masses. Such a correlation is found to be nonlinear, with the ratio between the two masses decreasing from 2X10^-4 for halos of 10^14 solar masses, to 10^-5 for halos of 10^12 solar masses. Preliminary evidence suggests that halos smaller than ~5X10^11 solar masses are increasingly less efficient -- perhaps unable -- at forming SBHs.
We generalize the Thomas-Fermi approach to galaxy structure to include self-consistently and non-linearly central supermassive black holes. This approach naturally incorporates the quantum pressure of the warm dark matter (WDM) particles and shows its full powerful and clearness in the presence of supermassive black holes (SPMHs). We find the main galaxy and central black hole magnitudes: halo radius r_h , halo mass M_h, black hole mass M_BH, velocity dispersion, phase space density, with their realistic astrophysical values, masses and sizes over a wide galaxy range. The SMBH masses arise naturally in this framework. Our extensive numerical calculations and detailed analytic resolution show that with SMBHs, both WDM regimes: classical (Boltzmann dilute) and quantum (compact) do necessarily co-exist in any galaxy: from the smaller and compact galaxies to the largest ones. The transition from the quantum to the classical region occurs precisely at the same point r_A where the chemical potential vanishes. A novel halo structure with three regions shows up: A small quantum compact core of radius r_A around the SMBH, followed by a less compact region till the BH influence radius r_i, and then for r> r_i the known halo galaxy shows up with its astrophysical size. Three representative families of galaxy plus central SMBH solutions are found and analyzed:small, medium and large galaxies having SMBH masses of 10^5, 10^7 and 10^9 M_sun respectively. A minimum galaxy size and mass ~ 10^7 M_sun larger than the one without SMBH is found. Small galaxies in the range 10^4 M_sun < M_h < 10^7 M_sun cannot harbor central SMBHs. We find novel scaling M_BH - r_h - M_h relations. The galaxy equation of state is derived: The pressure P(r) takes huge values in the SMBH vecinity and then sharply decreases entering the classical region following a local perfect gas behaviour.(Abridged)
This work aims at studying the $M_{BH}-M_{dyn}$ relation of a sample of $2<z<7$ quasars by constraining their host galaxy masses through full kinematical modeling of the cold gas kinematics, thus avoiding all possible biases and effects introduced by the rough virial estimates usually adopted so far. For this purpose we retrieved public observations of $72$ quasar host galaxies observed in ${rm [CII]_{158mu m}}$ or ${rm CO}$ transitions with the Atacama Large Millimeter Array (ALMA). We then selected those quasars whose line emission is spatially resolved and performed a kinematic analysis on ALMA observations. We estimated the dynamical mass of the systems by modeling the gas kinematics with a rotating disc taking into account geometrical and instrumental effects. Our dynamical mass estimates, combined with $M_{BH}$ obtained from literature and our own new ${rm CIV}lambda1550$ observations, have allowed us to investigate the $ M_{BH}/M_{dyn}$ in the early Universe. Overall we obtained a sample of $10$ quasars at $zsim2-7$ in which line emission is detected with high S/N ($> 5-10$) and the gas kinematics is spatially resolved and dominated by ordered rotation. The estimated dynamical masses place $6$ out of $10$ quasars above the local relation yielding to a $M_{BH}/M_{dyn}$ ratios $sim10times$ higher than those estimated in low-$z$ galaxies. On the other hand, we found that $4$ quasars at $zsim 4-6$ have dynamical-to-BH mass ratios consistent with what is observed in early-type galaxies in the local Universe.
In our modern understanding of galaxy formation, every galaxy forms within a dark matter halo. The formation and growth of galaxies over time is connected to the growth of the halos in which they form. The advent of large galaxy surveys as well as high-resolution cosmological simulations has provided a new window into the statistical relationship between galaxies and halos and its evolution. Here we define this galaxy-halo connection as the multi-variate distribution of galaxy and halo properties that can be derived from observations and simulations. This connection provides a key test of physical galaxy formation models; it also plays an essential role in constraints of cosmological models using galaxy surveys and in elucidating the properties of dark matter using galaxies. We review techniques for inferring the galaxy-halo connection and the insights that have arisen from these approaches. Some things we have learned are that galaxy formation efficiency is a strong function of halo mass; at its peak in halos around a pivot halo mass of 10^12 Msun, less than 20% of the available baryons have turned into stars by the present day; the intrinsic scatter in galaxy stellar mass is small, less than 0.2 dex at a given halo mass above this pivot mass; below this pivot mass galaxy stellar mass is a strong function of halo mass; the majority of stars over cosmic time were formed in a narrow region around this pivot mass. We also highlight key open questions about how galaxies and halos are connected, including understanding the correlations with secondary properties and the connection of these properties to galaxy clustering.
We analyze the intriguing possibility to explain both dark mass components in a galaxy: the dark matter (DM) halo and the supermassive dark compact object lying at the center, by a unified approach in terms of a quasi-relaxed system of massive, neutral fermions in general relativity. The solutions to the mass distribution of such a model that fulfill realistic halo boundary conditions inferred from observations, develop a highly-density core supported by the fermion degeneracy pressure able to mimic massive black holes at the center of galaxies. Remarkably, these dense core-diluted halo configurations can explain the dynamics of the closest stars around Milky Ways center (SgrA*) all the way to the halo rotation curve, without spoiling the baryonic bulge-disk components, for a narrow particle mass range $mc^2 sim 10$-$10^2$~keV.
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