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Weekly Seminars
 Tuesday June 10th, 2014 - 12,00 am Meeting Room - ICRANet (1st Floor)     ICRANet Seminar   Speaker: Prof. Érico Goulart Institution: DAMTP, Crambridge, UK Title: Nonlinear Wave Maps.     ************************************************** ICRANet Secretariat ICRANet Piazza della Repubblica, 10 65122 Pescara (PE) Italy tel.: +39 085 23054200 fax: +39 085 4219252 email: secretariat@icranet.org      Wednesday June 11th, 2014 - 4,00 pm Sala Lauree (Physics Dept., Old Building, 1st Floor)     ICRA Seminar   Speaker: Dr. Damien BEGUE 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 $10^{14} cm$.     N.B. - In the following link, you can find the official announcement on the Physics Department website: http://www.phys.uniroma1.it/fisica/sites/default/files/bollettini/bollettino09062014.pdf   ************************************************** La Segreteria ICRA c/o Dipartimento di Fisica Sapienza Università di Roma P.le A. Moro, 5 I - 00185 ROMA, Italy tel.: +39 06 4991 4 254 fax: +39 06 4454992 email: segreteria@icra.it         Thursday June 12th, 2014 - 4,00 pm Aula Conversi (Physics Dept., Old Building, 1st Floor)     Joint Astrophysics Seminar Department of Physics and ICRA   Speaker: Dr. Antonio RIOTTO 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.     N.B. - In the following link, you can find the official announcement on the Physics Department website: http://www.phys.uniroma1.it/fisica/sites/default/files/bollettini/bollettino09062014.pdf   ************************************************** La Segreteria ICRA c/o Dipartimento di Fisica Sapienza Università di Roma P.le A. Moro, 5 I - 00185 ROMA, Italy tel.: +39 06 4991 4 254 fax: +39 06 4454992 email: segreteria@icra.it         Monday June 16th, 2014 - 2,30 pm Aula Conversi (Physics Dept., Marconi Building, 1st Floor)     Joint Astrophysics Seminar - Department of Physics and ICRA   Speaker: Dr. Alessandro NAGAR 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.     N.B. - In the following link, you can find the non official announcement on the Physics Department website: https://agenda.infn.it/conferenceDisplay.py?confId=8206   ************************************************** La Segreteria ICRA c/o Dipartimento di Fisica Sapienza Università di Roma P.le A. Moro, 5 I - 00185 ROMA, Italy tel.: +39 06 4991 4 254 fax: +39 06 4454992 email: segreteria@icra.it

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