Between the extremes -- the physics of the first stars, galaxies, and black holes

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• Guido Roberts-Borsani (UCL)
• Friday 23 May 2025, 11:30-12:30
• Ryle Seminar Room, KICC + online.

If you have a question about this talk, please contact Sandro Tacchella.

The emergence of the first sources 13.6 billion years ago had a profound effect on the Universe, initiating its last major phase-change and ending the so-called Cosmic Dark Ages. Unlocking the physics of those primordial sources thus represents a fundamental step towards a comprehensive understanding of the initial conditions that formed the building blocks for the Universe we see today. While Hubble painted a fairly straight forward picture, early JWST data revealed an infant Universe far more remarkable and exotic than previously thought, with hyper-luminous galaxies detected out to z=14, chemically-enriched and Nitrogen-enhanced interstellar media out to z=12, and apparently over-massive black holes to z=10. Are these sources representative of the global population, or do they reflect peculiar objects at a particular evolutionary phase? In this talk I will present efforts to address these questions through the spectroscopic study of statistical samples of high-redshift (z>5-14) galaxies with JWST /NIRSpec, establishing a benchmark for their chemical enrichment journeys, ISM conditions, (re)ionizing capabilities, and spectroscopic fingerprints. Additionally, I will showcase the importance of utilizing unbiased samples of galaxies to gain representative insight into the ISM conditions and evolutionary pathways of the most luminous populations uncovered by JWST .

This talk is part of the Galaxies Discussion Group series.

This talk is included in these lists:

• Cambridge Astronomy Talks
• Combined External Astrophysics Talks DAMTP
• Cosmology, Astrophysics and General Relativity
• Galaxies Discussion Group
• Institute of Astronomy Talk Lists
• Kavli Institute for Cosmology Talk Lists
• Ryle Seminar Room, KICC + online

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