Nikolaus Sulzenauer

Master Student

Field of Interests

Looking at galaxies in the early universe, at about ten billion years look-back time, the build-up of stellar mass reached a peak. Signatures of this epoch are believed to be still present in the stellar populations of many early type galaxies. Extreme star-bursting galaxies are observed, producing optically thick dust clouds on galactic scales, with star-formation rates exceeding thousand solar masses per year.  Due to the shape of the SEDs, reaching maximum luminosity in the far-infrared, these galaxies are called “sub-mm galaxies” (SMGs). With the recent advent of highly sensitive detectors, sub-mm observatories – complementary to optical/NIR facilities– are bringing optically obscured star-forming galaxies into focus.

In my master thesis I will learn to apply optimal data-reduction of IRAM 30m EMIR spectroscopic data. This will enable the characterisation of two sub-mm galaxies at redshifts of 1.60 and 2.16 lensed by rich galaxy clusters. The SMGs were selected using their NIR/MIR flux and colour (Iglesias-Groth et al. 2017), corresponding to templates of lensed ultra-luminous sub-mm galaxies. As ground-based observations of extragalactic sub-mm sources are subject to challenging atmospheric and electronic noise, a careful data-reduction strategy is required. Once properly reduced, the EMIR spectra should provide sufficient S/N to measure individual CO-line profiles, fluxes and flux ratios. My aim is to build diagnostic CO spectral-line energy distributions, yielding insight into the extreme conditions of dusty star-forming galaxies in the early universe.