Weekly Seminars for January 2011

Thursday 20th January 2011 - 4:00 P.M.

Aula Conversi (Physics Dept., Old Building - 1st Floor)

Speaker:  Dr. Daniele Malesani (Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen - Denmark)

Title: The host galaxies of Gamma-Ray Bursts

Abstract: Gamma-Ray Bursts (GRBs) are powerful explosions occurring throughout the Universe and detectable up to high redshift. They come in two flavors, long and short, connected to different progenitors. This is witnessed by the different host galaxies in which they explode. Long GRBs are connected to the explosions of young, massive stars, therefore they are excellent probes of star-forming environments at high redshift. I will present a review of their host galaxy properties, focussing on recent results from our observational campaign. For short GRBs, host galaxies are one of the most promising ways to identify the progenitor mechanism, which is still eluding direct identification.

Wednesday 26th January 2011 - 4:00 P.M.

Aula Corbino (Physics Dept., New Building - 2nd Floor)

Speaker:  Dr. Rodrigo Picanço Negreiros (Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University - Germany)

Title: Thermal Properties of Compact Stars: what can we learn from it?

Abstract: Compact stars are the extraordinary remnants of massive stars that blew apart in violent supernova explosions. Due to their extreme properties, they present a wealth of physical phenomena that provide insight in the overlapping areas of nuclear physics, particle physics and relativistic astrophysics. With masses ranging between 1 and 2 solar masses and radii of around 10 km, these objects might be 20 times more dense than the atomic nuclei. Currently, the equation of state and composition prevailing at such extraordinary density are not known. In this talk I will explore different models for the microscopic composition of these stars, starting from the traditional neutron star model in which we assume that the star is composed solely of neutrons, protons and electrons; and ending at the more exotic ones, in which we study the possibility of hyperons and/or deconfined quark matter. The thermal evolution of compact stars, whose microscopic composition is given by the aforementioned models will be investigated. I will examine the quality of the underlying microscopic model by comparing our theoretical results with the available data on the thermal properties of compact stars. I will show that, as expected, the thermal evolution of compact stars strongly depends on the microscopic composition, especially on whether or not quark matter is found on the compact star. I will outline the properties of the thermal evolution presented by different models, and discuss the future outlook of this research.