Thesis Topic: Resolving the gas and dust in high-redshift galaxies

Thesis Supervisors:

 

Abstract

ALMA observations of gas and dust in galaxies over cosmic time are providing new constraints for a better understanding of the physical processes that ultimately control the baryonic evolution of galaxies (such as gas inflows and outflows and star formation). Especially resolved observations of gas and dust in and around galaxies hold a great promise to better understanding the baryonic evolution. 

In recent years, a number of studies have showed that the [CII] emission of high-redshift galaxies is generally more extended than their stellar emission. Other studies have demonstrated that the dust emission tends to be more compact. The former finding suggests that outflows might deposit enriched material in the circumgalactic medium around galaxies, whereas the latter points toward a buildup of stellar components in their central regions. Studies focusing on the dynamics of gas have revealed that the mass assembly of Milky-Way-type disks already started at redshifts ~4.5. However, all these studies so far have focused on a limited number of observations, and additional information is necessary to develop a sound picture.

The student will explore proprietary and archival ALMA data to study the morphology of gas and dust compared to the stellar component, their connection with the ongoing star formation, and the gas kinematics. The student will use stacking techniques to study the extent of sub-mm emission lines outside of galaxies, looking for additional evidence of chemical enrichment of the surrounding haloes by outflows. Furthermore, we will continuously apply for additional data to further support the project. The student may also use state-of-the-art galaxy formation simulations to study the resolved properties and dynamics of CO and [CII] in simulated galaxies, developing the physical framework needed to interpret the observations. The exact focus and a detailed time-line of the project will be determined together with the student.

References

  • Popping, G, 'ALMA reveals starburst-like interstellar medium conditions in a compact star-forming galaxy at z~2 using [CI] and CO', 2017, Astronomy & Astrophysics, Volume 602, id.A11, 10 pp.
  • Ginolfi,M, 'The ALPINE-ALMA [CII] Survey: CGM pollution and gas mixing by tidal stripping in a merging system at z~4.57', 2020, eprint arXiv:2004.13737
  • Ginolfi, M, 'The ALPINE-ALMA [C II] survey: Star-formation-driven outflows and circumgalactic enrichment in the early Universe', 2020, Astronomy & Astrophysics, Volume 633, id.A90, 14 pp. 
  • Popping, G, 'The ALMA Spectroscopic Survey in the HUDF: the Molecular Gas Content of Galaxies and Tensions with IllustrisTNG and the Santa Cruz SAM ', 2020, The Astrophysical Journal, Volume 882, Issue 2, article id. 137, 25 pp. (2019).
  • Fujimoto, S, 'First Identification of 10 kpc [C II] 158 μm Halos around Star-forming Galaxies at z = 5─7 ', 2019, The Astrophysical Journal, Volume 887, Issue 2, article id. 107, 17 pp.
  • Kaasinen, M, 'A Comparison of the Stellar, CO, and Dust-continuum Emission from Three Star-forming HUDF Galaxies at z ∼ 2', 2020, The Astrophysical Journal, Volume 899, Issue 1, id.37