Thesis Supervisor: Gergo Popping

Abstract:

The redshift range of z ∼ 1 − 3, dubbed Cosmic Noon, is the peak epoch of star formation and black hole activity in the Universe and an important epoch for the cosmic cycle of baryons in and out of galaxies, a complex and multi-phase process at the core of galaxy formation and evolution. During this epoch, vast quantities of gas were accreted onto galaxies from the cosmic web, which cooled, condensed, and collapsed to form stars, which then enriched the interstellar medium (ISM). The ISM conditions are known to be significantly different at z ∼ 2 compared to z ∼ 0, making local galaxies unsuitable for understanding the baryon cycle at this key epoch. Yet, there are still no combined observations of the fuel for star formation (molecular gas), star formation rate (SFR), and gas-phase and solid-phase metals (metallicity and dust) in the typical population of star-forming galaxies at Cosmic Noon. The recently approved ALMA large program 'ALMA Chemical Evolution (ACE) survey' will change this picture by constraining the gas and dust mass, respectively, for a representative sample of 25 star-forming galaxies at z = 2.0 − 2.5 that cover a wide, so-far unexplored, range in stellar mass, metallicity and star-formation rate. ACE will  link metals in gas-phase to those locked up in dust grains to constrain the buildup of dust and will reveal the fundamental role of molecular gas reservoirs in shaping the mass-metallicity relation, for the first time in a range of galaxies at Cosmic Noon. 

The program furthermore provides a rich set of serendipitously detected field galaxies for which deep multi-wavelength dust-continuum and in some cases CO line information is available. These targets are perfectly suited for detailed characterisation of the physical properties of cold dust in Cosmic Noon galaxies and/or the characterisation of cold dust in passive galaxies.

In this project the student will become part of the ACE team and work on topics related to cold gas, dust, metals and obscured star-formation in normal star-forming galaxies at cosmic noon to better understand the buildup and ISM properties of low-mass galaxies at the epoch when our Universe was most actively forming stars. This will be achieved by leveraging data from the ALMA Chemical Evolution survey, combined with data from ground and space based observatories such as JWST, the VLT and Keck.