The Dyadosphere of Black Holes and Gamma-Ray Bursts

Recent works on the Dyadosphere are reviewed.Comment: A&A macros, 4 pages and 3 figures. To appear in the proceedings of 19th Texas Symposium, Dec. 199

Black Hole Formation and Gamma Ray Bursts

Recent work on the dyadosphere of a black hole is reviewed with special emphasis on the explanation of gamma ray bursts. A change of paradigm in the observations of black holes is presented.Comment: 10 pages, 4 figures, to appear in the proceedings of the ESO workshop on "Black Holes in Binaries and Galactic Nuclei", in honour of Prof. R. Giacconi, edited by L. Kaper, E.P.J. van den Heuvel, and P.A. Woudt, and printed in the series ESO Astrophysics Symposia by Springer (2000

Moments with Yakov Borisovich Zeldovich

A recollection of special moments spent with Yakov Borisovich Zeldovich and with the scientists of Soviet Union and abroad.Comment: To appear in the proceedings of the international conference "The Sun, the Stars, The Universe and General Relativity" in honor of Ya.B. Zeldovich 95th Anniversary, held in Minsk, Belarus on April 20-23, 200

Charges in gravitational fields: from Fermi, via Hanni-Ruffini-Wheeler, to the "electric Meissner effect"

Recent developments in obtaining a detailed model for gamma ray bursts have shown the need for a deeper understanding of phenomena described by solutions of the Einstein-Maxwell equations, reviving interest in the behavior of charges close to a black hole. In particular a drastic difference has been found between the lines of force of a charged test particle in the fields of Schwarzschild and Reissner-Nordstrom black holes. This difference characterizes a general relativistic effect for the electric field of a charged test particle around a (charged) Reissner-Nordstrom black hole similar to the "Meissner effect" for a magnetic field around a superconductor. These new results are related to earlier work by Fermi and Hanni-Ruffini-Wheeler.Comment: 25 pages, 17 figures, to appear on the Proceedings of "Analysis, manifolds and geometric structures in physics", International Conference in Honour of Y. Choquet-Bruhat, Isola d'Elba June 24th-26th, 200

Analogies, new paradigms and observational data as growing factors of Relativistic Astrophysics

Patterns in the scientific developments of Relativistic Astrophysics are analyzed with special attention to the physics and astrophysics of Black Holes and Gamma Ray Bursts.Comment: 28 pages, 14 figures, to appear in "Fluctuating Paths and Fields - Dedicated to Hagen Kleinert on the Occasion of His 60th Birthday", Eds. W. Janke, A. Pelster, H.-J. Schmidt, and M. Bachmann (World Scientific, Singapore, 2001), p. 77

On the exact analytic expressions for the equitemporal surfaces in Gamma-Ray Burst afterglows

We have recently shown (see Bianco & Ruffini 2004) that marked differences exist between the EQuiTemporal Surfaces (EQTSs) for the Gamma-Ray Burst (GRB) afterglows numerically computed by the full integration of the equations of motion and the ones found in the current literature expressed analytically on the grounds of various approximations. In this Letter the exact analytic expressions of the EQTSs are presented both in the case of fully radiative and adiabatic regimes. The new EQTS analytic solutions validate the numerical results obtained in Bianco & Ruffini (2004) and offer a powerful tool to analytically perform the estimates of the physical observables in GRB afterglows.Comment: 3 pages, 1 figure, to appear on ApJ Letter

Introducing the black hole

The quasi-stellar object, the pulsar, the neutron star have all come onto the scene of physics within the space of a few years. Is the next entrant destined to be the black hole? If so, it is difficult to think of any development that could be of greater significance. A black hole, whether of “ordinary size” (approximately one solar mass, 1 M⊙) or much larger (around 10^6 M⊙ to 10^10 M⊙, as proposed in the nuclei of some galaxies), provides our “laboratory model” for the gravitational collapse, predicted by Einstein's theory, of the universe itself