Weekly Seminars for September 2008

Monday 1st September 2008

ICRANet,  Pescara - Seminars Room

Speakers:  Sandip K. Chakrabarti (S.N. Bose National Centre for Basic Sciences and Indian Centre for Space Physics) 
  Sonali Chakrabarti (M.M.C. College and Indian Centre for Space Physics)

Title: Chemical Evolution of bio-molecules during star formation

Abstract: Discovery of amino acids in meteorites suggests that many of the complex pre-biotic molecules could indeed be formed during the collapse of the interstellar clouds before the actual star formation took place. We carry out such studies using complete grain and gas chemistry. We use rate equation method, master equation method as well as the Monte-Carlo method to show evolution of lighter molecules in the grain phase and subsequently desorb them to the gas phase and evolve them to produce more complex molecules. Our results generally match with observations for lighter molecules. However, for complex molecules the result is not so conclusive. We believe that this is due to our poor knowledge of the reaction pathways and the reaction cross-section for complex molecules.

Thursday 18th September 2008, 5:00 P.M.

ICRANet,  Pescara - Seminars Room

Speaker:  Prof. W.Greiner
Institution: Frankfurt Institute for Advanced Studies (FIAS) Johann Wolfgang Goethe - Universität Frankfurt/Main GERMANY

Title: Superheavy elements - theoretical expectations and experiments

Abstract: I will describe the theoretical concepts and ideas underlining the search of superheavy elements starting from the traditional shell-model; its foundation trough meson theory. The predictions for magic numbers are discussed based on the two-centre-shell-model. Potential energy surfaces are calculated and the stability of the elements against fission, alpha decays and electron capture are investigated. The experiments done at GSI, at Dubna and at RIKEN (Japan) are presented. Finally the open problems will be described.

Presentation: PPT

Thursday 25th September 2008, 4:00 P.M.

ICRANet,  Pescara - Seminars Room

Speaker:  Prof. Yu-Qing Lou
Institution: Physics Department and Tsinghua Center for Astrophysics
Tsinghua University - Beijing, China

Title: Formation of Supermassive Black Holes in Galactic Bulges

Abstract: Growing evidence indicate supermassive black holes (SMBHs) in a mass range of M_{bh}~ 106-1010 M_{sun} lurking in central stellar bulges of galaxies. Extensive observations reveal power laws of M_{bh versus the mean stellar velocity dispersion \sigma of the host stellar bulge. The dynamic evolution of a host bulge and the formation of a central SMBH should be physically linked. We reproduce the empirical M_{bh}-\sigma power laws on the basis of our recent theoretical model analyses for a self-similar general polytropic quasi-static dynamic evolution of spherical bulges with self-gravity under spherical symmetry and present a physical criterion of forming a central SMBH. The key result is M_{bh}=L\sigma^{1/(1-n)} where 2/3<n<1 and L is a proportional coefficient characteristic of host bulges. By fitting and comparing several empirical M_{bh}-\sigma power laws, we conclude that SMBHs and galactic bulges grow and evolve in a coeval manner and most likely there exist several classes of galactic bulge systems in quasi-static self-similar evolution.

Paper on "Supermassive Black Holes in Galactic Bulges": PDF