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Saul
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There are multiple fundamental problems with the explaining or the explaining away of observations related to the mass evolution with redshift of the super massive object that is believed to be found in almost all galaxies.
Weight Gain Problem - Early Universe
Fast Gain Problem
SMB's at approximately z=6 are 10^9 solar masses. To reach that mass the massive object must continuously grow at the Eddington limit in the early universe.
Stop Eating Problem
The most massive SMBs observed are less than 10^10 solar masses. A second problem is how to explain why the SMBs are very, very effective in mass gain and then suddenly stop growing.
Baby SMB Problem - Local Universe
A third problem is how does one explain our galaxy's baby 3.0 10^6 solar mass massive object based on the age of our galaxy.
Dark Matter Bing Problem
A fourth problem that must be explain is why does run away mass gain due to dark matter in fall not occur? Dark matter should clump around the massive SMB in the center of the galaxies. Why does it not clump?http://arxiv.org/abs/0808.2813
http://arxiv.org/PS_cache/arxiv/pdf/0709/0709.0545v1.pdf
Weight Gain Problem - Early Universe
Fast Gain Problem
SMB's at approximately z=6 are 10^9 solar masses. To reach that mass the massive object must continuously grow at the Eddington limit in the early universe.
Stop Eating Problem
The most massive SMBs observed are less than 10^10 solar masses. A second problem is how to explain why the SMBs are very, very effective in mass gain and then suddenly stop growing.
Baby SMB Problem - Local Universe
A third problem is how does one explain our galaxy's baby 3.0 10^6 solar mass massive object based on the age of our galaxy.
Dark Matter Bing Problem
A fourth problem that must be explain is why does run away mass gain due to dark matter in fall not occur? Dark matter should clump around the massive SMB in the center of the galaxies. Why does it not clump?http://arxiv.org/abs/0808.2813
Is there an upper limit to black hole masses?
We make a case for the existence for ultra-massive black holes (UMBHs) in the Universe, but argue that there exists a likely upper limit to black hole masses of the order of M approx. 10^10 Mass Solar. We show that there are three strong lines of argument that predicate the existence of UMBHs: (i) expected as a natural extension of the observed black hole mass bulge luminosity relation, when extrapolated to the bulge luminosities of bright central galaxies in clusters; (ii) new predictions for the mass function of seed black holes at high redshifts predict that growth via accretion or merger-induced accretion inevitably leads to the existence of rare UMBHs at late times; (iii) the local mass function of black holes computed from the observed X-ray luminosity functions of active galactic nuclei predict the existence of a high mass tail in the black hole mass function at z = 0. Consistency between the optical and X-ray census of the local black hole mass function requires an upper limit to black hole masses.
http://arxiv.org/PS_cache/arxiv/pdf/1002/1002.0553v1.pdfRecent simulation work that follows the merger history of cluster scale dark matter halos and the growth of BHs hosted in them by Yoo et al.(2007) also predict the existence of a rare population of local UMBHs. However, theoretical arguments suggest that there may be an upper limit to the mass of a BH that can grow in a given galactic nucleus hosted in a dark matter halo of a given spin. Clearly the issue of the existence of UMBHs is intimately linked to the efficiency of galaxy formation and the formation of the largest, most luminous and massive galaxies in the Universe.
An upper limit to the central density of dark matter haloes from consistency with the presence of massive central black holes
We therefore must conclude that the central regions of large dark haloes have coexisted with massive black holes over most of the history of the universe. Given the existence of event horizons associated to black holes, and the assumption of standard cold dark matter subject only to gravitational interactions, it follows that central black holes have grown over the history of galactic dark haloes, through the capture of dark matter particles.
We find the process to be characterised by the onset of a rapid runaway growth phase after a critical timescale. This timescale is a function of the mass of the black hole and the local density of dark matter. By requiring that the runaway phase does not occur, as then the swallowing up of the halo by the black hole would seriously distort the former, we can obtain upper limits to the maximum allowed density of dark
matter at the centres of haloes.
We note that once the mass of the central black hole grows substantially, processes not included here would begin to become relevant, and would invalidate the simple physical hypothesis leading to eq. (4). Some include: the adiabatic contraction of the dark halo in response to the concentration of mass into the central black hole, resulting in higher central dark matter densities and hence even higher accretion rates; the accretion of a fraction of the baryons into the central black hole, which is known to occur; or the enhanced
gravitational focusing of matter of all types into the black hole, once the approximation of the black hole mass being small compared to the total halo mass which we are working under begins to break down. All of these make it reasonable to assume that the first corrections to eq. (4) will lead to even larger accretion rates, hence leaving our conclusions, in terms of limit densities, unchanged.
Comparing the upper limiting central dark matter density of 250M_ pc−3 with the dynamically inferred structure of galactic dark haloes, it is reassuring that when a constant density core is used to model observations, the inferred central dark matter densities always lie below this limit, typically at ' 1M_ pc−3, or below. Recent examples are given by Gilmore et al. (2007) for local dwarf spheroidal galaxies, and de Blok et al. (2008) for late type galaxies. Hence no conflict appears, in that the runaway accretion regime for the central black hole will not be reached in 10 Gyr for any directly inferred values of the central dark matter density, for any inferred central black hole masses.
http://arxiv.org/PS_cache/arxiv/pdf/0709/0709.0545v1.pdf
Did supermassive black holes form by direct collapse?
Despite years of study, we still do not know how the seeds of supermassive black holes formed. Few if any of the pathways in Martin Rees’s famous flow chart (Begelman & Rees 1978) can be ruled out, but none of the routes is particularly well understood, either. What we do know is that some very massive (> 10^9M⊙) black holes had to exist by z approx 6 in order to explain early quasars (Fan 2006). If the seeds of these black holes were the remnants of massive stars, then they must have grown by Eddington-limited accretion formost of the time since their formation, or else much of their growth was due to mergers. A second possibility is that the seeds formed by such a rapid accumulation of matter that it may be considered to be a direct collapse. I will focus on the latter possibility in this paper.
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