Hidden star formation in the early Universe

Leeuwen, I. F. van (2026)

Doctoral Thesis

In this thesis, both the obscured and unobscured star formation of high-redshift galaxies (UV-bright galaxies and serendipitously identified [CII]-emitters) is investigated. For this purpose, observations from multiple telescopes are used: the Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile, the Hubble Space Telescope, and the James Webb Space Telescope (JWST). The results show that a significant portion of star formation in the early Universe may be hidden by dust. In addition, some galaxies have properties that make them difficult to detect with JWST, but are visible with ALMA. This shows that ALMA is an essential instrument for studying the early Universe: it can observe hidden star formation and identify galaxies that would otherwise be missed by JWST.

• High-redshift
• Galaxies
• Star formation rate
• Obscured star formation
• ALMA
• JWST
• Dust-obscured
• REBELS
• Companion galaxies

• All authors: Leeuwen, I. F. van
• Supervisor: Werf, P.P. van der
• Co-supervisor: Bouwens, R.J.; Hodge, J.A.
• Committee: Snellen, I.A.G.; Rottgering, H.J.A.; Kriek, M.T.; Hennawi, J.F.; Caputi, K.I.; Shivaei, I.
• Qualification: Doctor (dr.)
• Awarding Institution: Leiden Observatory, Faculty of Science, Leiden University
• Date: 2026-04-09
• ISBN (print): 9789465342825
• DOI: doi:10.60602/1887-4301034