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- I am a software developer and author of computer books. I also work on some problems in theoretical physics. For more... moreI am a software developer and author of computer books. I also work on some problems in theoretical physics. For more information, please visit my personal Web site at https://www.vttoth.com/.edit
The lensing and Einstein ring at the core of the galaxy cluster Abell 3827 are reproduced in the modified gravity theory MOG. The estimated effective lensing mass M_L=(1+α)M_b=5.2× 10^12 M_ within R=18.3 kpc for a baryon mass M_b=1.0×... more
The lensing and Einstein ring at the core of the galaxy cluster Abell 3827 are reproduced in the modified gravity theory MOG. The estimated effective lensing mass M_L=(1+α)M_b=5.2× 10^12 M_ within R=18.3 kpc for a baryon mass M_b=1.0× 10^12 M_ within the same radius produces the observed Einstein ring angular radius θ_E=10”. A detailed derivation of the total lensing mass is based on modeling of the cluster configuration of galaxies, intra cluster light and X-ray emission. The MOG can fit the lensing and Einstein ring in Abell 3827 without dark matter as well as General Relativity with dark matter.
We present calculations for the anticipated shadow sizes of Sgr A* and the supermassive black hole in the galaxy M87 in the context of the MOG modified theory of gravity (also known as Scalar– Tensor–Vector–Gravity, or STVG). We... more
We present calculations for the anticipated shadow sizes of Sgr A* and the supermassive black hole in the galaxy M87 in the context of the MOG modified theory of gravity (also known as Scalar– Tensor–Vector–Gravity, or STVG). We demonstrate that mass estimates derived from stellar and gas dynamics in the vicinity of these black holes are the Newtonian masses of the black holes even in the MOG theory. Consequently, shadow sizes increase as a function of the key dimensionless MOG parameter α that characterizes the variable gravitational coupling coefficient G, and may offer an observational means to distinguish the MOG theory from standard general relativity.
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We investigate the contributions of the Friedmann–Lemaître–Robertson–Walker metric of the standard cosmology as an asymptotic boundary condition on the first-order approximation of the gravitational field in Moffat’s theory of modified... more
We investigate the contributions of the Friedmann–Lemaître–Robertson–Walker metric of the standard cosmology as an asymptotic boundary condition on the first-order approximation of the gravitational field in Moffat’s theory of modified gravity (MOG). We also consider contributions due to the fact that the MOG theory does not satisfy the shell theorem or Birkhoff’s theorem, resulting in what is known as the “external field effect” (EFE). We show that while both these effects add small contributions to the radial acceleration law, the result is orders of magnitude smaller than the radial acceleration in spiral galaxies.
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The remarkable optical properties of the solar gravitational lens (SGL) include major brightness amplification ([Formula: see text] on the optical axis, at a wavelength of [Formula: see text]m) and extreme angular resolution ([Formula:... more
The remarkable optical properties of the solar gravitational lens (SGL) include major brightness amplification ([Formula: see text] on the optical axis, at a wavelength of [Formula: see text]m) and extreme angular resolution ([Formula: see text][Formula: see text]arcsec). A deep space mission equipped with a modest telescope and coronagraph, traveling to the focal area of the SGL that begins at [Formula: see text] astronomical units (AU) from the Sun, offers an opportunity for direct megapixel imaging and high-resolution spectroscopy of a habitable Earth-like exoplanet. We present a basic overview of this intriguing opportunity.
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) in which the Eddington-Robertson parameters for our modified gravity theory (MOG) are derived. We show by explicit calculation that the role of the vector field $\phi_\mu$ cannot be ignored in this derivation.
An electroweak model in which the masses of the W and Z bosons and the fermions are generated by quantum loop graphs through a symmetry breaking is investigated. The model is based on a regularized quantum field theory in which the... more
An electroweak model in which the masses of the W and Z bosons and the fermions are generated by quantum loop graphs through a symmetry breaking is investigated. The model is based on a regularized quantum field theory in which the quantum loop graphs are finite to all orders of perturbation theory and the massless theory is gauge invariant, Poincare invariant, and unitary. The breaking of the electroweak symmetry SU(2) X U(1) is achieved without a Higgs particle. A fundamental energy scale of ~542 GeV (not to be confused with a naive cutoff) enters the theory through the regularization of the Feynman loop diagrams. The theory yields a prediction for the W mass that is accurate to about 0.5% without radiative corrections. The scattering amplitudes for WW -> WW and e+e- -> WW processes do not violate unitarity at high energies due to the suppression of the amplitudes by the running of the coupling constants at vertices.
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An electroweak model in which the masses of the W and Z bosons and the fermions are generated by quantum loop graphs through a symmetry breaking is investigated. The model is based on a regularized quantum field theory in which the... more
An electroweak model in which the masses of the W and Z bosons and the fermions are generated by quantum loop graphs through a symmetry breaking is investigated. The model is based on a regularized quantum field theory in which the quantum loop graphs are finite to all orders of perturbation theory and the massless theory is gauge invariant, Poincare invariant, and unitary. The breaking of the electroweak symmetry SU_L(2) X U_Y(1) is achieved without a Higgs particle. A fundamental energy scale \Lambda_W (not to be confused with a naive cutoff) enters the theory through the regularization of the Feynman loop diagrams. The finite regularized theory with \Lambda_W allows for a fitting of low energy electroweak data. \Lambda_W ~ 542 GeV is determined at the Z pole by fitting it to the Z mass m_Z, and anchoring the value of \sin^2\theta_w to its experimental value at the Z pole yields a prediction for the W mass m_W that is accurate to about 0.5% without radiative corrections. The scattering amplitudes for W_LW_L -> W_LW_L and e+e- -> W_L^+W_L^- processes do not violate unitarity at high energies due to the suppression of the amplitudes by the running of the coupling constants at vertices. There is no Higgs hierarchy fine-tuning problem in the model. The unitary tree level amplitudes for W_LW_L -> W_LW_L scattering and e+e- -> W_L^+W_L^- annihilation, predicted by the finite electroweak model are compared with the amplitudes obtained from the standard model with Higgs exchange. These predicted amplitudes can be used to distinguish at the LHC between the standard electroweak model and the Higgsless model.
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ABSTRACT Using recently developed nonrelativistic numerical simulation code, we investigate the stability properties of compact astrophysical objects that may be formed due to the Bose-Einstein condensation of dark matter. Once the... more
ABSTRACT Using recently developed nonrelativistic numerical simulation code, we investigate the stability properties of compact astrophysical objects that may be formed due to the Bose-Einstein condensation of dark matter. Once the temperature of a boson gas is less than the critical temperature, a Bose-Einstein condensation process can always take place during the cosmic history of the universe. Due to dark matter accretion, a Bose-Einstein condensed core can also be formed inside massive astrophysical objects such as neutron stars or white dwarfs, for example. Numerically solving the Gross-Pitaevskii-Poisson system of coupled differential equations, we demonstrate, with longer simulation runs, that within the computational limits of the simulation the objects we investigate are stable. Physical properties of a self-gravitating Bose-Einstein condensate are examined both in non-rotating and rotating cases.