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PX444 The Distant Universe

Lecturer: Andrew Levan

Weighting: 7.5 CATS

Recent observations are beginning to reach back into the Cosmic Dawn - the era when the first stars and galaxies formed. The physical conditions at the time of their formation set the properties of these objects, and their evolution in turn sets the properties of the stars, galaxies and planets that follow. This module investigates the formation of structure in the early Universe, starting from the Cosmic Microwave Background and moving through the first generations of stars, and onto the large scale structures that we see today.

The module discusses the theory behind the formation of the first stars and galaxies from primordial density perturbations, the build-up of mass through hierarchical structure formation and the importance of feedback in shaping galaxies. It also highlights current observations being conducted to directly observe distant structures, which formed when the Universe was less than 5% of its current age. It outlines the insight that arises from them, and discusses how new observations with missions set for launch in the next few years might answer the remaining, central questions in the field.

To study what is known about the Universe to the limits of current observations and beyond, to identify gaps in current knowledge and to look at future prospects.

By the end of the module, students should:

  • have a qualitative understanding of the evolution of the early universe, from the Big Bang to the development of large scale structure
  • understand the physics underlying theories of galaxy and structure formation, and how observations inform those theories
  • be aware of the range and significance of observational evidence for stars, galaxies and structure in the distant Universe.

The module will explore the evolution of structure in the Universe, its physical explanations and interpretation, and the techniques used by astronomers to probe the early stages of galaxy formation and evolution.
1. Setting the initial conditions. The Big Bang; Inflation and Nucleosynthesis; the Cosmic
Microwave Background radiation and its interpretation.
2. Reionization; the first stars and galaxies; 21cm radiation and the temperature history of the Universe
3. Probes of the Distant Universe; Lyman break galaxies; AGN and supermassive black holes; gamma ray bursts; Submillimeter galaxies and radio galaxies.
4. The evolution of the Universe; metallicity evolution; the star formation rate history of the Universe; luminosity function evolution.
5. The formation of large-scale structure; the Cosmic Web; baryon acoustic oscillations.

Commitment: 15 lectures

Assessment: 1.5 hours

The module has a website.

Recommended texts: Loeb & Furlanetto, The First Galaxies in the Universe, Princeton, 2013.