Licenciate Thesis: Kinematic Porpoerties of Star Forming Galaxies from far+UV absorption line spectroscopy
Thursday 19 February 2015
to 13:00 at
Thøger-Emil Rivera-Thorsen (Stockholm University, Department of Astronomy)
The Lyman-α line is currently one of our most important observational windows to the high-redshi Universe. With 68% of ionizing photons emitted inside HI sys- tems being reprocessed into Lyα, and HI being by far the most abundant neutral species in the Universe, it is clear that Lyα makes up a very high fraction of in- trinsic radiation from star-forming regions, AGN or other places, where hydrogen gets ionized and is dense enough to recombine. However, Lyα is a resonant tran- sition with a large interaction cross section, leading to complex radiative transfer effects which can strongly redistribute Lyα readiation both geometrically and in frequency space. Thus while the strength of the Lyα line makes it possible to observe galaxies and similar scale systems at indeed very high redshifts, correct interpretation of these observations requires a detailed understanding of the inner workings of galaxies and their ISM, in which the radiative transfer happens.
The research presented here is part of a larger, joint effort to im- prove our knowledge of these effects, possibly benefiting the larger extragalactic astronomy community.
Mvh T. Emil Rivera-Thorsen