A Sub-mm perspective on massive galaxies in the early universe

Schouws; S.T.M. (2026)

Doctoral Thesis

This thesis investigates the formation, kinematics, and interstellar medium (ISM) properties of massive galaxies in the early Universe (z~7-14) using sub-millimeter observations from the Atacama Large Millimeter/submillimeter Array (ALMA).

By probing dust continuum emission in luminous Lyman-break galaxies at z~7-8, this work demonstrates that approximately one-third of their star formation is obscured by dust, favoring steep, supernova-driven attenuation curves. Through targeted [CII]158um blind spectral scans, an efficient method for spectroscopically confirming galaxies in the Epoch of Reionization is established, uncovering substantial kinematic diversity spanning ordered rotating discs, major mergers, and dispersion-dominated systems.

Pushing to Cosmic Dawn, the robust detection of [OIII]88um in JADES-GS-z14-0 confirms its spectroscopic redshift at z=14.1793, revealing surprisingly rapid chemical enrichment (Z~0.2-0.5) a mere 300 million years after the Big Bang. Subsequent deep constraints on [CII]158um and dust continuum emission in this galaxy indicate extreme ionization conditions (log U > -2.0), low gas density, and a depleted gas reservoir (f_gas < 0.77), consistent with a system shaped by strong feedback in a dynamic post-outflow phase.

• High-redshift galaxies
• Galaxy evolution
• Lyman-break galaxies
• Submillimeter astronomy
• Interstellar medium
• Interstellar dust
• Emission line galaxies
• Galaxy kinematics
• Galaxy feedback

• All authors: Schouws; S.T.M.
• Supervisor: Röttgering, H.J.A.
• Co-supervisor: Bouwens, R.J.; Hodge, J.A.
• Committee: Kriek, M.T.; Werf, P.P. van der; Hennawi, J.F.; Matthee, J.J.A.; Stefanon, M.
• Qualification: Doctor (dr.)
• Awarding Institution: Leiden Observatory, Faculty of Science, Leiden University
• Date: 2026-09-01