Institution: SAPIENZA Università di Roma & ICRANet Pescara

Title: On the structure of circumburst medium in the fireshell model of Gamma-Ray Bursts.

Abstract: In the fireshell model, the extended afterglow of Gamma-Ray Bursts (GRBs) is emitted when a relativistically expanding shell interacts with massive structures (clouds) of the circumburst medium. The spectra are computed by assuming that the emission is thermal in the frame co-moving with the shell. The reproduction of the peak energy requires the introduction of the filling factor $\mathcal{R}$ that is interpreted as the ratio of the area emitting over the total area of the shell. It is deduced that the circumburst medium is composed of filaments.
In this paper, we consider the interaction between the shell and a filament rather than between the shell and a cloud, as done in the fireshell model. The assumption that the emission is thermal requires the optical depth $\tau$ to be larger than one. We use this additional constraint to determine a regime of deceleration compatible with the variability time scale of GRBs. We find that the observations can be reproduced when a massive cloud of $10^{-4}$ solar mass is placed at a radius of the order of $10^{14} cm $.  

Institution: University of Geneva - Switzerland

Title: BICEP, B-mode polarization of the CMB and gravity waves from primordial inflation.

Abstract: We will discuss the implications of the recent detection of B-mode polarization of the CMB by the BICEP collaboration if it is ascribable to the gravity waves generated during primordial inflation.  

Institution: Institut des Hautes Etudes Scientifiques, Bures-sur-Yvette (Paris) - France

Title: The effective-one-body (EOB) modelling of coalescing compact binaries.

Abstract: I will review the state-of-the-art analytic effective one body (EOB) approach to the general-relativistic two-body dynamics and its completion using numerical relativity (NR) simulations. I will discuss in detail three cases: i) coalescence of (spinning) black hole binaries (BBHs); ii) tidal effects in coalescing neutron star binaries and the EOS-universality at merger; iii) the BBH scattering problem and the determination of the scattering angle in EOB and NR. I will present several examples about how NR simulations c! an inform the EOB model so to build a comprehensive EOBNR model of the two-body dynamics and waveforms in general relativity. Implications for gravitational wave data analysis are discussed.