PhD Part A exam by Karen Pardos Olsen – Niels Bohr Institutet - Københavns Universitet

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PhD Part A exam by Karen Pardos Olsen

DARK's PhD Student, Karen Pardos, will present her Part A PhD Exam Friday 11 January 2013 at 10:00 in the DARK lounge. Karen's supervisor is Sune Toft.

Title: "Active galactic nuclei and molecular gas in massive z~2 galaxies"

The star formation rate (SFR), as a function of cosmic time, of massive galaxies tells us a puzzling story of their evolution. In this talk, I will present my work on two galaxy components that are both believed to have a strong say on the SFR of massive galaxies at z ~ 2; the first being capable of terminating it, the second being the very fountain of which stars emerge:

1) Active Galactic Nuclei (AGNs)
AGNs have been proposed at the cause of star formation quenching both at high and low redshift. With the deep X-ray observations available today, we can measure the AGN fraction of massive galaxies to higher redshifts than before. I will discuss the results of using the Chandra X-ray observatory to asses the AGN fraction in quiescent vs. star-forming massive galaxies at z ~ 2 (Olsen, K. P. et al. 2012) and talk about follow-up projects.

2) Molecular gas
How does molecular gas in galaxies evolve into stars? To answer this question, we must first be able to determine the gas properties which means to correctly interpret molecular line observations. I have developed a code (SIGAME) that can simulate the molecular emission lines, and I will present preliminary results as well as future applications.