Weekly Seminars for March 2011

Thursday 3rd March 2011 - 4:00 P.M.

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

Speaker:  Dr. Roberto Peron (Istituto di Fisica dello Spazio Interplanetario (IFSI-INAF), Roma - Experimental Gravitation Group)

Title: Einstein is still right: new tests of gravitation in the field of the Earth

Abstract: General relativity theory by Albert Einstein is still the best and most effective available description of gravitational phenomena, supported by an impressive series of experimental tests on a very wide range of scales. Nevertheless, evidences of various nature (particle physics, cosmology) have placed many times and still place questions on its validity and overall coherence; alternative theories of gravitation have been in fact proposed along the years. In this context, the experimental tests in the Solar System remain an important tool and, perhaps not surprisingly, continue to be among the strongholds of knowledge in this field. In particular, LAGEOS satellites turned out to be among the most powerful tools in order to probe the fine characteristics of the gravitation phenomenon, and continue to provide extremely interesting results. Their particular orbits and the extremely precise tracking technique (Satellite Laser Ranging) turned out to be fundamental and led along the years to a series of important discoveries. It will be presented and discussed in particular a recent analysis, which led to the first direct verification of Schwarzschild relativistic precession in the field of the Earth, and to the measurement of the so-called Lense-Thirring and de Sitter effects; emphasis will be given on the analysis methodology, the modelization and the related error estimates. It will be also shown a further result, consisting in a new limit, much more stringent than the previous ones, on a possible non Newtonian (Yukawa) interaction, acting at the scale of Earth radius.


Thursday 10th March 2011 - 11:00 A.M.

Sala Lauree (Physics Dept., Old Building - 1st Floor)

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

Title: Cooling of hot, young neutron stars

Abstract: The thermal processes taking place in a proto neuton stars (the object that preceeds neutron star) has been extensively studied in the literature. The cooling of neutrons stars with ages greater than 500 hundred years has also been investigated to great details. In this work we discuss the exciting possibility of probing the initial thermal evolution of a young, hot neutron star, immediately after the proto neutron star regime. With the help of data from GRB's we will show that the current picture of the cooling of neutron stars need to be extended, to approprietly describe the physics governing hot and young neutron stars.


Friday 18th March 2011 - 4:00 P.M.

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

Speaker:  Prof. Philippe Jetzer (Institute of Theoretical Physics, University of Zurich - Switzerland)

Title: Pixel lensing as a way to detect extrasolar planets in M31

Abstract: I will give an overview of the so far achieved results with microlensing observations towards the Large Magellanic Clouds and the Andromeda (M31) galaxy. In particular I will disscus what we learned for dark matter in form of compact objects in the halo of our and M31 galaxies and focus on the possibility to detect extrasolar planets in M31 using microlensing techniques.


Thursday 31st March 2011 - 4:00 P.M.

Sala Direzione INFN (Physics Dept., Old Building - 2nd Floor)

Speaker:  Dr. She-Sheng Xue (ICRANet & Physics Dept., SAPIENZA University of Rome)

Title: A study of neutrino productions in gravitational collapses

Abstract: In order to catch some sight of neutrino production in gravitational collapsing processes, we try to find a simplified model to calculate neutrino production rate based on equilibrium conditions of microscopic processes, provided microscopic process rates are much larger than macroscopic process ones. The preliminary results are consistent with numerical simulations and observational data.