Tuesday, August 03, 2021

Gentral engine of galactic nuclei as a time reversed blackhole-like object

The work to be summarize was inspired by a Quanta Magazine article "Physicists Identify the Engine Powering blackhole Energy Beams" (see this) telling about an empirical support for the model of Blandford and Znajek (BZ model in the sequel) for the central engine providing energy for jets from active galactic nuclei (AGNs). In the BZ model (see this) AGN is identified as a blackhole and the Penrose process would provide the energy of the jets emerging from the blackhole. The energy would come basically from the blackhole mass. The empirical support is found by studying the supermassive blackhole associated with a galaxy known as Messier 87 (M87).

The basic problem is the identification of the central engine of the active galactic nuclei (AGNs) (see this) providing the huge energy feed to the the jets.

1. Typical properties of active galactic nuclei

The power emitted by active galactic nuclei (AGNs) is typically of the order of 1038 W corresponding to a transformation of a mass of 1022 kg per second to energy. The typical radius of the AGN is R ≈ 2 AU for the active region.

One must distinguish between magnetic fields associated with the interior of the central objects, the region near its surface, and the jet region with the scale of visible jets about 105 ly. According to the estimate of (see this), the magnetic field is about 10 Gauss in the jet region. About 106-107 Gauss near horizon. Also near-horizon magnetic fields in the range 108-1011 Tesla have been proposed for some AGNs.

Quasars are examples of AGNs and also M87 central region idenfied as a blackhole is such. In this case the mass is 6.5× 109MSun and Scwartschild radius is about 2× 1010 km = 1.3× 103 AU. For M87 central object the magnetic field in the jet region is that of refrigerator magnet and about 100 Gauss. For Sagittarius A has a in the center of the Milky Way the radius of the central object .4 AU.

One can pose some general conditions on the central engine serving as the energy source for the jets. The time scale Δt for the luminosity fluctuations in the power should satisfy Δt< R. For M87 one has Δt ≤ 104 s. The gravitational force is assumed to be balanced by the radiation pressure of the outward radiation.

Consider now the observations about the M87 blackhole-like entity (see this).

  1. The mass of the M87 black-hole-like entity is about 6.5× 109MSun.
  2. There are two 5,000 ly long white hot plasma jets travelling in opposite time directions with emitted power of 3× 1036 W. They have blobs at their ends. Synchrotron radiation is emitted at radio wavelengths in the magnetic field, which according to the popular article has the strength of a refrigerator magnet, so that one would have B ≈ 100 Gauss. Both the intensity of B and the size of the emitting region contribute to the intensity of the energy flow.
  3. There are two alternatives for the BZ process that have been developed and explored in hundreds of computer simulations in recent decades. They have acronyms MAD and SANE.

    For the SANE option B is weak: charged matter dominates over B. For the MAD option B is strong, has a spiral structure and acts as a "boss" of the matter. The tight spiral structure forms a sleeve around the jet preventing charges from entering the central object. This inspires a critical question: doesn't the object look more like a whitehole.

    The strongly polarized light in the Event Horizon Telescope's new photo suggests strong magnetic fields, and supports the MAD version. B has a strength of about 100 Gauss, that is 200 times the strength of the Earth's magnetic field with the nominal value BE≈ .5 Gauss. The polarization pattern for the radio waves is found to be stripy and the polarization in a plane locally: this allows us to conclude that the magnetic field is indeed helical and non-random.

2. Central engine as a Penrose process?

In the BZ model, the central object is assumed to be a blackhole and Penrose process would provide the energy feed to the jets of length about 5000 ly. Note that the Milky Way is about 1,0000 ly thick.

  1. The blackhole is surrounded by an accretion disk from which the matter ends down to the BH.
  2. Kerr solution of Einstein-Maxwell field equations (this) involving magnetic field is the starting point. Matter falling into the Kerr blackhole rotates and the magnetic field lines are twisted to helical shape. By Faraday law, an electric field along field lines is generated by the rotation of the flux lines. Electrons and positrons created in the annihilation photons emitted as the particles fall to the region near the blachole, start to flow along the field lines of the electric field in opposite directions and generate the jets.
  3. The model assumes that the electromagnetic field is force free so that it does not dissipate and Lorentz force vanishes. At a single particle level this implies the condition E+qv× B=0. Vanishing dissipation requires v· E=0. This helical structure would be in the direction of the jet.
  4. The basic question has been whether it is accretion disk or magnetic field that controls the dynamics. The first option, known as SANE, corresponds to weak and incoherent magnetic fields. The second option, known as MAD, corresponds to strong and coherent magnetic fields.
  5. MAD is favoured by the recent observations. Magnetic field would form a sleeve around the jet and the synchrotron radiation pressure would prevent matter from falling into the blackhole. Matter can only occasionally leak to blackhole.

    One can however wonder whether it makes sense to talk about blackhole anymore! Doesn't this look more like white hole as a time reversal of blackhole feeding energy and matter to the environment?

3. TGD inspired view of the central engine

In the TGD framework the model of the central engine as a Penrose process is replaced by the following picture. The key concepts are following:

  1. Space-time is identified as a 4-D minimal surface in H=M4× CP2 or as an algebraic surface in complexified M8 having octonionic interpretation. These descriptions are related by M8-H duality analogous to momentum-position duality, which does not generalize from wave mechanics to quantum field theory (QFT). Therefore the points or M8 are 8-momenta.

    The classical dissipation is absent for the generalized Beltrami fields and the proposal is that minimal surfaces (apart form singularities defining dynamically generated frame for space-time surfaces as analog of a soap film) define locally generalized Beltrami fields.

  2. Zero energy ontology (ZEO) predicts that time reversal occurs in the TGD counterparts of ordinary state function reductions ("big" SFRs) but not in "small" SFRs (SSFRs).
  3. The hierarchy of effective Planck constants predicts a hierarchy of phases of ordinary matter labelled by the values of effective Planck constant heff= nh0. The phases with different values of heff behave in many respects like dark matter with respect to each other. The findings of Randell Mills suggest ℏ/ℏ0=6 but also larger values for this ratio can be considered. I have proposed that the ℏ0/ℏ is equal to the ratio lP/R of Planck length lP to CP2 radius R.

    As a special case, one obtains gravitational Planck constant satisfying heff= hgr= GMm/β0, where β0=v0/c and β0<c has dimensions of velocity, as a generalization of Nottale's hypothesis. The gravitational Compton length λgr=ℏgr/m=GM/β0 does not depend on m and is equal to Schwartschild radius rs for β0= 1/2. Also the cyclotron energy spectrum Ec=n GMqB/β0 is independent of the mass of the charged particle.

    The hierarchy of Planck constants, the notion of ℏgr, and coupling constant evolution are discussed in detail here.

Consider next the key elements of the model.
  1. TGD leads to a general model for the formation of galaxies, stars, planets,... in terms of cosmic strings thickening to flux tubes. The energy of the flux tube, which consists of a volume energy and Kähler magnetic energy, is transformed to ordinary matter as the string tension is reduced in a sequence of phase transitions reducing the length scale dependent cosmological constant λ.

    This process is analogous to the decay of an inflaton field to matter. The model (there are actually several basic variants of it) explains the flat velocity spectra associated with the spiral galaxies. For the first option, a long cosmic string normal to the galactic plane causes the gravitational field explaining the flat velocity spectrum of spiral galaxies. For galaxies formed around closed flux loops the velocity spectrum is not flat. There is no dark matter halo although it is possible that the galactic plane contains cosmic strings parallel to the plane.

  2. Zero energy ontology (ZEO), which predicts that the TGD counterparts of ordinary state function reductions (SFRs) involve time reversal, is involved in an essential manner. TGD predicts both blackhole-like objects (BH) and whitehole-like objects (WH) as the time reversals of BHs. The seed of the galaxy, active galactic nucleus (AGN), involves WH. Quasars are cases of AGNs as WHs.
  3. In the TGD framework, the Kerr blackhole is replaced with a whitehole-like object (WH). Kerr blackhole indeed has an opposite arrow of time reversal as the distant environment. The WH is time reversal of BH and feeds matter and energy to the environment. This serves as an analog of the Penrose process in the TGD based model.
  4. The TGD analog for the rotation of spacetime and the twisting of the magnetic field lines near the Kerr blackhole is very concrete. Space-time is a 4-surface and the flux tubes carrying monopole flux are pieces of 3-space as a 3-surface. They quite concretely rotate and get twisted in the process. Analogous process occurs in the Sun with a period of 11 years ending as reconnections untwist the flux tubes.
  5. WH would correspond to a tangle of a long cosmic string in the direction of the jet thickened to a flux tube but still carrying an extremely strong magnetic field. The helical magnetic field in the exterior of the jet would not represent return flux of this field as one might first think. There is a current ring associated with the equator of Earth, which carries a parallel magnetic field analogous to the helical magnetic field.

    The magnetic field in the exterior of WH is associated with a space-time surface, which is many-sheeted with respect to CP2 rather than M4 so that either CP2 or cosmic string world sheet M2× S2⊂ M4× CP2) would serve as the arena of physics rather than M4, which is quantum coherent flux tube bundle analogous to BE-condensate. M4 coordinates as functions of CP2 or M2× CP2 coordinates would be many-valued rather than vice versa. This picture is very natural if one accepts M8-H duality.

    Cosmic strings dominate during the primordial cosmology in TGD Universe, and the analog of the inflationary period corresponds to the transition to a phase in which the Einsteinian space-time with M4 as the arena of physics is a good approximation. Hence the M2× CP2 option looks more plausible.

  6. The force-free em fields appearing in the BZ model correspond to space-time surfaces as minimal surfaces realizing a 4-D generalization of 3-D Beltrami fields, which do not not dissipate classically. The interpretation of the non-dissipating Kähler currents is as classical correlates for supracurrents. The prediction is that charged particles flow without dissipation that is as supra currents: not only Cooper pairs but also charged fermions. Also the analogs of laser beams of dark photons are expected.
  7. The hierarchy of Planck constants is an important piece of the picture emerging from adelic physics. From ℏgr=GMm/β0 realizing Equivalence Principle, the gravitational Compton length λgr= rs/2β0 is universal and equals to rS for β0== β0=1/2.

    All astrophysical objects are predicted to be quantum coherent in the scale of λgr= rs/2β0 at least. The quantum coherence would be at the level of magnetic body (MB). WH/BH as a thickened flux tube tangle would not have large heff but would be accompanied by a large scale quantum object.

    The astroscopic quantum coherence would be associated with the helical magnetic field surrounding the long cosmic string having BH or WH as a tangle.

  8. Also the cyclotron energy spectrum is universal and does not depend on the mass of the charged particles so that all charged particles rather than only electrons are expected to form supracurrents. Dark matter would flow along flux tubes and form the dark core of the jet, perhaps extending over cosmic distances to other galaxies identified as tangles of the one and the same cosmic string.

    Stars and even planets would be parts of this fractal network. Dark cyclotron states have huge energies for heff=hgr serving also as a measure for algebraic complexity and, in the TGD inspired theory of consciousness, also for intelligence and scale of quantum coherence. The analogy with a cosmic nervous system is obvious.

  9. The decay of quantum coherent states to ordinary states takes place by the loss of quantum coherence in which heff= hgr is reduced. This would create the visible jets and blobs at their ends. For M87, which is elliptical for which the velocity spectrum is not flat, the flux tubes would be closed in a relatively short scale. Their length scale could be that of the jets in the case of ellipticals. The thickening of the cosmic string at the core leads to the reduction of mass of WH and gives rise to the flow of mass and energy to the environment. One could see this process as a time reversal for the generation of BH and perhaps also as an analogy for the evaporation of BH.
  10. M8-H duality and adelic physics help to understand the decoherence process geometrically. The reduction of heff and thus of the length scale of quantum coherence, allows a number theoretic description at the level of M8. An irreducible polynomial, which depends on parameters, reduces to a product of polynomials for some critical values of the parameters. This gives rise to a set of disjoint space-time surfaces, which are not correlated. This means decoherence. This includes as a special case the description of catastrophic changes in catastrophe theory of Thom. The maximal decoherence produces a product of first order polynomials with rational roots.

    At the level of H =M4×CP2 this corresponds to a decay of coherent flux tube bundle to disjoint uncorrelated flux tubes.

See the article TGD view of the engine powering jets from active galactic nuclei or the chapter with the same title.

For a summary of earlier postings see Latest progress in TGD.

Articles and other material related to TGD.

No comments: