Master Thesis defense by Jiaming Yao
Title: The Optical and Infrared Properties of Dusty Star-forming Galaxies in ALCS
Abstract: Dust is a powerful proxy for studying formation of stars and interstellar molecules, and its radiation contributes largely to cosmic infrared background (CIB) which carry information about how early galaxies evolve. The considerable amount of UV radiation produced by these young stars is hidden in the dust around galaxies, thus studying properties of dust can help us reveal a more comprehensive picture of star formation in the early universe. In this thesis, we use photometric catalogues from ALMA Lensing Cluster Survey (ALCS) based on the data of the Hubble Space Telescope (HST) and Spitzer, combining ALMA 1.2mm maps to identify and study properties of dusty star-bursting candidates at z = 0 ∼ 5. We first directly match sources in optical/NIR catalogues with those in 1.2mm catalogues, then we compare matched objects with color-color diagrams and results of SED fitting to select dusty star-forming candidates. To derive dust mass and total infrared luminosity, we use 1.2mm data to rescale modified black body. Star formation rates are calculated based on UV and infrared luminosity and compared to confirmed relationships in SFR-M⋆ plane. The main results are that for galaxies with notable far-infrared radiation, the combination of UV and IR indicators can describe star formation activity of dusty candidates better than SED fitting, and the U V J diagram can distinguish quiescent galaxies and dusty galaxies with high accuracy.
Supervisors:
- Georgios Magdis, University of Copenhagen, Niels Bohr Insitute
- Francesco Valentino, University of Copenhagen, Niels Bohr Insitute
Censor:
- Allan Hornstrup, DTU Space