Logo.ADPast, present and future of the Intergalactic Medium Cosmology (a European perspective)

Prof. Stefano Cristiani s Tržaškega astronomskega observatorija bo predaval o intergalaktični snovi (izjemoma) v torek, 19. 3. 2013, ob 13. uri v predavalnici F3 na FMF, Jadranska 19, Ljubljana. Vabljeni!

Prejšnja predavanja so na razpolago na spletni strani Astrodebate.

Povzetek predavanja:

The history of the universe during and soon after the Dark Age is recorded in the all-pervading intergalactic medium (IGM), which is believed to contain most of the ordinary baryonic material resulting out of the big bang. Throughout the epoch of structure formation, the IGM became clumpy and acquired peculiar motions under the influence of gravity and acted as a reservoir for the gas that gets accreted, cools and forms stars within galaxies and as a sink for the metal-enriched material, energy and radiation which they eject.

Along the line of sight to a distant source - a quasar, a gamma-ray burst, a galaxy - every parcel of IGM gas selectively absorbs certain wavelengths of light due to the presence of the various chemical elements in it. Through the analysis of these absorption lines we can study the spatial distributions, motions, chemical enrichment, and ionization histories of gaseous structures from redshift seven and beyond until the present. From few details of little apparent significance, it is possible to deduce a surprising number of important conclusions about our Universe, especially when we link the information provided by absorption lines with the complementary information derived from the evolutionary properties of luminous galactic structures.

The study of the IGM has enormously developed in the last 50 years, and so the contribution of Europe to it, overcoming the initial handicap of collecting power, detectors and tradition.