Department of Physics, Panjab University, Chandigarh, India

TPSC seminar

Time and date: 5 October 2012 (Friday), 4:00 pm
Venue: Seminar Hall

Title: Metal and dust content of the universe as determined through QSO absorption lines

Speaker: Prof. Pushpa Khare, CSIR Emeritus Scientist, IUCAA, Pune

Abstract: Absorption lines seen in the spectra of quasi-stellar objects (QSOs) have proved to be a very sensitive and powerful tool in understanding the evolutionary history of the universe. They have enabled us to observe, indirectly, galaxies and intergalactic matter at large distances, which are virtually inaccessible otherwise, and have provided a means to observationally verify the predictions of theoretical models of structure formation and evolution. Recently the Sloan Digital Sky Survey (SDSS) has provided unprecedented wealth of data and has yielded a large homogeneous sample of QSO absorption line systems. The talk will focus on (i) the chemical enrichment history of the universe based on our recent observations of the strongest of the absorption line systems i.e. the damped Lyman alpha systems combined with other observations reported in the literature and (ii) the average metal and dust content of the intermediate and high redshift QSO absorbers from the analysis of SDSS data which have provided, for the first time, convincing evidence for the presence of dust in the intervening and associated absorbers.