| Belinsky Volodia |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
On the equilibrium state for two
charged masses in General Relativity V.Belinski, R.Ruffini and G. Vereschagin |
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Abstract: |
It was found the exact
relativistic equilibrium condition for the Reissner-Nordstrom black hole
and charged spinning particle (represented by the Kerr-Newman naked
singularity solution) to be in the rest with respect to each other. The
problem was solved analytically by the Inverse Scattering Method by which
the exact solution for the metric and electromagnetic potentials have been
obtained. Some physical properties of this solution was analyzed using
numerical calculations. To show a novelty of the results a review of the previous literature on this problem is presented. |
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| Arkhangelskaja Irene |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
A possibility of existance third
GRB class - intermediate GRBs Arkhangelskaja I.V. |
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Abstract: |
In the present work the
possibility of existance third GRB group was studied. We have analysed duration and hardness GRB distributions from last (current) BATSE catalog and make conclusion that GRB with mean value of t90=3 sec (0.8 s < t90 < 25 s) had dirrerent hardness distribution that long and short GRB and can be separated as new GRB subset - intermediate GRB. Some characteristics of this class GRB are presented. |
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| Bernardini Maria Grazia |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
TBA | ||
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Abstract: |
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| Bianco Carlo Luciano |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
Equations of motion of GRBS | ||
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Abstract: |
The exact analytic solutions of the equations of motion of Gamma-Ray Burst afterglows are presented, both in the fully radiative and in the adiabatic regimes. Such exact solutions are compared and contrasted with the formulas usually adopted in the current literature, based on various approximations. The consequences of using the approximate solutions, instead of the exact ones, in computing the equitemporal surfaces and consequently in comparing the theoretical predictions with the observations are discussed. |
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| Bini Donato |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
Spinning test particles: formalisms in comparison and applications. | ||
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Abstract: |
The motion of (maaive, massless) spinning test particles in general relativity is reviewed re-formulating the Mathisson-Papapetrou equations using different approaches: Frenet-Serret, Newman-Penrose, Geroch-Held-Penrose etc. Applications to some familiar spacetimes are presented. | ||
| Capaccioli Massimo | Director of Naples observatory | ||
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Title of talk: |
TBA | ||
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Abstract: |
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| Carlevaro Nakia |
ICRA (International
Center for Relativistic Astrophysics) c/o Department of Physics, University of Rome "La Sapienza", P.le Aldo Moro, 5 - 00185 - Roma - Italy |
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Title of talk: |
Bulk Viscosity Effects on the
Early Universe Stability Nakia Carlevaro, Giovanni Montani |
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Abstract: |
We present a discussion of the
effects induced by the bulk viscosity on the very early Universe
stability. The matter filling the cosmological (isotropic and homogeneous) back ground is described by a viscous fluid having an ultrarelativistic equation of state and whose viscosity coefficient is related to the energy density via a power-law. The analytic expression of the density contrast shows that, for small values of the proportional constant of the power-law, its behavior is not significantly different from the non-viscous one derived by E.M. Lifshitz. But as soon it overcomes a critical value, the growth of the density contrast is suppressed forwarding time by the viscosity and the stability of the Universe is favored in the expanding pictures. On the other hand, in such a regime, the asymptotic approach to the initial singularity is deeply modified by the apparency of significant viscosity in the primordial thermal bath i.e. the isotropic an homogeneous Universe admits an unstable collapsing picture. In our model this feature regards also scalars perturbations while in the non-viscous case it appears only for tensor modes. |
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| Chardonnet Pascal | |||
| Title of talk: |
The high z effects in GRBS |
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Abstract: |
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| Cianfrani Francesco |
ICRA (International
Center for Relativistic Astrophysics) |
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| Title of talk: |
Geometrization of the electro-weak model
bosonic component in a Kaluza-Klein approach |
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Abstract: |
We present the geometrization of the electro-weak model bosonic component in a 7-dimensional and in a 8-dimensional space-time manifold through a Kaluza-Klein approach, then we introduce spinorial matter fields and we achieve the conservation of gauge charges and the geometrization of gauge connections; finally through a scalar field we are able to reproduce the spontaneous symmetry breaking mechanism. | ||
| Filippi Simonetta | |||
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Title of talk: |
TBA | ||
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Abstract: |
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| Fraschetti Federico |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
Swift sources of GRBS | ||
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Abstract: |
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| Geralico Andrea |
Dipartimento di Fisica, Università di Lecce, and INFN,
Sezione di Lecce, Via Arnesano, CP 193, I-73100 Lecce, Italy and ICRA (International Center for Relativistic Astrophysics) c/o Department of Physics, University of Rome "La Sapienza", P.le Aldo Moro, 5 - 00185 - Roma - Italy |
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Title of talk: |
TBA | ||
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Abstract: |
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| Ghisellini | |||
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Title of talk: |
TBA | ||
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Abstract: |
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| Guida Roberto |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
TBA | ||
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Abstract: |
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| Gurzadyan Vahe |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
The possible contribution of the vacuum modes into the dark energy and its relation to CMB properties and geometry and topology of the Universe, will be discussed. | ||
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Abstract: |
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| Iorio Lorenzo | |||
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Title of talk: |
The new opportunities opened by the recent CHAMP/GRACE models for testing the Lense-Thirring effect with a new satellite | ||
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Abstract: |
In this talk we investigate the
opportunities offered by the new Earth gravity models from the dedicated
CHAMP and, especially, GRACE missions to the project of measuring the
general relativistic Lense-Thirring effect with a new Earth's artificial
satellite (Iorio 2005). It turns out that it would be possible to abandon
the stringent, and expensive, requirements on the orbital geometry of the
originally prosed LARES mission (same semimajor axis a=12270 km of the
existing LAGEOS and inclination i as closest as possible to 70 deg) by
inserting the new spacecraft in a relatively low, and cheaper, orbit
(a=7500-8000 km, i near 70 deg) and suitably combining its node Omega with
those of LAGEOS and LAGEOS II in order to cancel out the first even zonal
harmonic coefficients of the multipolar expansion of the terrestrial
gravitational potential J_2, J_4 along with their temporal variations. The
total systematic error due to the mismodelling in the remaining even zonal
harmonics would amount to near 1% and would be insensitive to departures
of the inclination from the originally proposed value of many degrees. No
semisecular long-period perturbations would be introduced because the
period of the node, which is also the period of the solar K_1 tidal
perturbation, would amount to near 100 days. Since the coefficient of the
node of the new satellite would be smaller than 0.1 for such low
altitudes, the impact of the non-gravitational perturbations of it on the
proposed combination would be negligible. Then, a particular financial and
technological effort for suitably building the satellite in order to
minimize the non-conservative accelerations would be unnecessary. Such an
orbital configuration, which should fit the requirements of, e.g., the
proposed OPTIS mission (Laemmerzahl et al. 2004), could also be useful for
some geodetic purposes like a better estimation of the Earth's GM (Ries et
al. 2005) in the context of the Internation Terrestrial Reference Frame.
However, a real breakthrough in measuring the Lense-Thirring effect on the
orbit of a test particle could only be obtained with at least a couple of
entirely new spacecraft endowed with some active mechanism of compensation
of the non-gravitational perturbations. This would allow to discard the existing passive LAGEOS satellites which set the obtainabletotal accuracy to near 1% due to the uncancelled non-conservative forces acting on them. References. |
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| Lattanzi Massimiliano |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
On the interaction between primordial gravitational waves and relic neutrinos | ||
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Abstract: |
We investigate the interaction between gravitational waves produced in the early Universe, and the cosmological relic neutrinos. We find that gravitational waves produced at T>1 GeV are nearly completely absorbed due to the presence of the neutrino anisotropic stress. The implications with respect to the detectability of a cosmological signal by the LISA space interferometer are discussed. | ||
| Lacquaniti Valentino |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
On the hamiltonian approach to a 5-D Kaluza-Klein model | ||
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Abstract: |
We present a discussion about the hamiltonian formulation of a 5-D Kaluza-Klein model, via an ADM splitting. We exam the possibility to impose KK condition after ADM splitting and show how the time-component of the gauge vector is related to the fourth component of the shift vector. | ||
| Mattei Alvise |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
Ultrahigh Energy Cosmic rays | ||
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Abstract: |
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| Nagar Alessandro |
Dipartimento di Fisica del Politecnico di Torino and INFN, sezione di Torino |
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Title of talk: |
Gravitational radiation from
accretion onto Schwarzschild black holes. Thick accretion disks. Alessandro Nagar, Matteo Luca Ruggiero, Angelo Tartaglia |
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Abstract: |
The features of the gravitational radiation generated by accretion onto a Schwarzschild black hole will be discussed. A hybrid procedure is adopted, where one solves, in axial symmetry and in the time-domain, the gauge-invariant even and odd-parity master equations for metric perturbations of a Scharzschild black hole (i.e. the Zerilli-Moncrief and the Regge-Wheeler equations respectively) with matter source represented by a perfect fluid thick accretion disk with polytropic equation of state. The dynamics of the matter is evolved by means of a state-of-the-art axisymmetric High-Resolution-Shock-Capturing hydrodynamics code. I consider Different initial models are considered, which can simply oscillate around an equilibrium position or plunge into the hole. We argue that, in astrophysically motivated scenarios, the GWs signal is likely to be dominated by fluid modes rather than by the quasi-normal-modes ringing of the black hole. | ||
| Rotondo Michael |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
On the Relativistic Collapse of the Atom | ||
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Abstract: |
It is found an analogy between the relativistic treatment of a system of a self-gravitating degenerate fermions in a white dwarf and a system of degenerate fermions in an atom. The intoduction of special relativity leads to the concept of critical mass against gravitational collapse for a white dwarf. Using, for an atom, the polytropic scaling laws introduced by Landau in the case of white dwarf we show that a concept of relativistic collapse have to exist, in the case of an atom, for initial value Z~3.67(1/137)^(3/2). | ||
| Ruffini Remo |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
GRBS enlightening the Dark Universe | ||
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Abstract: |
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| Sancisi | |||
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Title of talk: |
TBA | ||
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Abstract: |
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| Sigismondi Costantino |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
Fermions in the Expanding Universe | ||
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Abstract: |
Phase
space and Fermi sea are usually concepts left out in secondary school's
programs. Simple examples on their introduction to young students will be
discussed. Visive approaches have to be united to analitical and numerical treatments. The following topics will be briefly reviewed: Phase space and Pauli principle; Fermi sea and Fermi energy in metals and gravitationally bound systems; the static Universe and the stationary Universe; the expanding Universe and Meszaros effect; free streaming and gravitational collapse in expanding Universe, also with excel. |
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| Vereshchagin Gregory |
ICRA (International
Center for Relativistic Astrophysics) |
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Title of talk: |
On the Cavallo-Rees classification
and GRBs Authors: R. Ruffini, G.V. Vereshchagin and S.-S. Xue |
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Abstract: |
There is a consensus in the literature that the cosmological fireball model gives a good description of the gamma ray bursts phenomenon. Cavallo and Rees in their pioneering work provided a qualitative picture of the cosmic fireball evolution. They also defined a parameter space for initial conditions of the fireballs. We show how this parameter space is constrained within the model of bursts based on energy extraction from electromagnetic black hole. Some insights into the problem of experimental verification of this model with the help of Cavallo and Rees diagram will be presented. |