Antonio Feoli

IS THERE A RELATIONSHIP BETWEEN THE MASS OF A SMBH AND THE KINETIC ENERGY OF ITS HOST ELLIPTICAL GALAXY

We use a restricted sample of elliptical galaxies, whose kinematical parameters inside the semi-major axis were calculated correcting for the effect of the integration of the light along the line of sight, in order to analyze a possible relationship between the mass of a supermassive black hole (SMBH) and the kinetic energy of random motions in the host galaxy. We find MBH ∝ (MG σ2)α with 0.87 ≤ α ≤ 1 depending on the different fitting methods and samples used. This result could be interpreted as a new fundamental relationship or as a new way to explain the old MBH - σ law. In fact, the relations of the velocity dispersion both with the mass of the SMBH (MBH ∝ σ4.12) and with the mass of the host galaxy (MG ∝ σ2.16) induce us to infer an almost direct proportionality: MBH ∝ MGσ2. A similar relationship is found for the total kinetic energy involving the rotation velocity too.

MAXIMAL ACCELERATION OR MAXIMAL ACCELERATIONS

We review the arguments supporting the existence of a maximal acceleration for a massive particle and show that different values of this upper limit can be predicted in different physical situations.We review the arguments supporting the existence of a maximal acceleration for a massive particle and show that different values of this upper limit can be predicted in different physical situations.

The SMBH mass versus MGσ2 relation: a comparison between real data and numerical models

The relation between the mass of supermassive black holes located in the center of the host galaxies and the kinetic energy of random motions of the corresponding bulges can be reinterpreted as an age–temperature diagram for galaxies. This relation fits the experimental data better than the M•−MG, M•−LG, and M•−σ laws. The validity of this statement has been confirmed by using three samples extracted from different catalogues of galaxies. In the framework of the ΛCDM cosmology our relation has been compared with the predictions of two galaxy formation models based on the Millennium Simulation.

A FUNDAMENTAL EQUATION FOR SUPERMASSIVE BLACK HOLES

We developed a theoretical model that is able to give a common origin to the correlations between the mass M• of supermassive black holes and the mass, velocity dispersion, kinetic energy and momentum parameter of the corresponding host galaxies. Our model is essentially based on the transformation of the angular momentum of the interstellar material, which falls into the black hole, into the angular momentum of the radiation emitted in this process. In this framework, we predict the existence of a relation of the form M• ∝ Reσ3, which is confirmed by the experimental data and can be the starting point to understand the other popular scaling laws too.

Unruh temperature with maximal acceleration

In this paper, we modify the geometry of Rindler space so as to include an upper limit on the acceleration. Caianiello and his collaborators, in a series of papers, have analyzed the corrections to the classical spacetime metrics due to the existence of a maximal acceleration. Our goal is to derive, in this context, in a very simple way, the so-called Unruh temperature.

Cosmological constraints from supernova data set with corrected redshift

Observations of distant type Ia supernovae (SNe Ia), used as standard candles, support the notion that the Cosmos is filled with a mysterious form of energy, the dark energy. The constraints on cosmological parameters derived from data of SNe Ia and the measurements of the cosmic microwave background anisotropies indicate that the dark energy amounts to ≈ 70% of all the energy contained in the Universe. In the hypothesis of a flat Universe (Ωm + ΩΛ = 1), we investigate if the dark energy is really required in order to explain the SNe Ia experimental data, and, in this case, how much of such unknown energy is actually deduced from the analysis of these data and must be introduced in the ΛCDM model of cosmology. In particular we are interested in verifying if the Einstein–de Sitter model of the expanding Universe is really to be ruled out. By using a fitting procedure based on the Newton method search for a minimum, we reanalyzed the Union compilation reported by Kowalski et al. (2008) formed by 307 SNe, obtaining a very different estimate of the dark energy, that is ≈ 60%. Furthermore, in order to balance the correction of the apparent magnitude of SNe Ia, due to the dilation or stretching of the corresponding light curve width, we introduce a suitable modified redsfhit. Taking into account this correction, we refitted the Union compilation dataset after a selection cut. The main result that emerges from our analysis is that the values of Ωm and ΩΛ strongly depend on the fitting procedure and the selected sample. In particular, the constraint we obtain on the mass density, normalized by the critical mass density, is Ωm = 0.7 for a sample of 252, and Ωm = 1 for a sample of 242 SNe Ia respectively. The latter case does not imply the existence of any additional form of dark energy.

Some remarks about underused Loedel diagrams

We emphasize that it can be didactically very useful for students to realize how a space–time diagram of an observer, moving with a constant velocity with respect to another observer, can be obtained easily by means of a standard matrix of rotation, without recourse to imaginary axes and angles. These diagrams were introduced for the first time by Loedel and their main advantage over Minkowski diagrams is that a scale factor is not necessary to convert the units of an observer to those of another observer. We show this well-known property of Loedel diagrams using a new geometric approach.

A little help for a better understanding and application of Faraday's law

In this letter, we examine Faradays law of induction, analysing the electromotive force generated by a Lorentz force and the one generated by an electric field due to a changing magnetic field. We obtain the result in a didactically simple and appealing way. The final formula is derived considering explicitly the dependence of the magnetic field on the space coordinates, which is often neglected in standard textbooks.

ELECTROMAGNETIC SHAPE RESONANCES OF A DIELECTRIC SPHERE AND RADIATION OF PORTABLE TELEPHONES

The frequency band used by cellular telephones includes the eigenfrequencies of a dielectric sphere with physical characteristics close to those of a human head. Proceeding from the spatial features of the natural modes of such a sphere, we propose an independent and clear evident accuracy test for the complicated numerical calculations which are conducted when estimating the potential hazard due to the use of cellular telephones, in particular, for the check of the proper handling of the electromagnetic shape resonances of a human head.

SOME PREDICTIONS OF THE COSMOLOGICAL SCHRÖDINGER EQUATION

Starting from the apparently periodic structures of the universe, revealed in a series of recent observations, we suppose that Dark Matter is composed of a quantum particle of very low mass and is clustered around the luminous matter of galaxies. We reduce the cosmological Friedman–Einstein dynamical system to a sort of Schrodinger equation for this quantum particle with a simple first quantization scheme. Comparing the eigen-solutions of this Cosmological Schrodinger Equation with the experimental periodic large scale structure, we predict the possible value of the mass of the dark quantum particle in two remarkable cases.