Astrophysics and Cosmology

ALESSANDRO MELCHIORRI

GENERAL OBJECTIVES:
The course aims to provide an overview as complete as possible on the most recent and important results in the field of theoretical and experimental cosmology. In particular, the three main observational evidences for the Big Bang scenario will be discussed: the recession of the galaxies, the primordial nucleosynthesis and the cosmic background radiation. A significant part of the program will be devoted to the study of the anisotropies of cosmic background radiation.

SPECIFIC OBJECTIVES:
A - Knowledge and understanding
OF 1) Ability to derive Friedmann equations starting from General Relativity and FRW metric.
OF 2) To understand the observational methods that have allowed a verification of the current cosmological model.
OF 3) To identify current model issues and discuss possible future developments.
B - Application skills
OF 4) To know how to determine the value of some cosmological parameters starting from different cosmological observables.
C - Autonomy of judgment
OF 5) Being able to understand what are the fundamental characteristics that a cosmological theory must possess in order to have a good agreement with current observations.
E - Ability to learn
OF 6) Have the ability to read scientific papers in order to further explore some of the topics introduced during the course.

Classical mechanics. Electromagnetism. Special relativity. Non-relativistic quantum mechanics.

Friedmann's cosmological model. Friedmann equations. Energy components. Baryonic matter and dark matter. Cosmological constant. Deceleration parameter. Age of the universe. Angular distance and luminosity distance in cosmology. Hubble law. Measurement of the Hubble constant. Standard candles and standard sirens. Evidence for dark energy through measurements of SN-Ia luminosity distances. Current accelerating universe: theoretical models and problems. Primordial universe and relativistic components. Cosmic background radiation (CMB) and its black body spectrum. Estimation of the energy component in neutrinos through CMB measurements. Primordial nucleosynthesis and abundance of light elements. Estimation of the number of neutrino families by primordial nucleosynthesis. Energy component in massive neutrinos. Limits on neutrino mass from cosmological observations. Structure formation on cosmological scales.Jeans lenght. Temporal evolution of perturbations in linear regime for baryonic and obscure components. The problems of the standard model and the inflationary paradigm. Inflationary models. Primordial spectrum of inflationary fluctuations. Power spectrum of the fluctuations and comparison with current data. Anisotropy of cosmic background radiation and its formation mechanisms. Angular spectrum of anisotropic fluctuations and dependence on cosmological parameters. Polarization of CMB, scalar and tensor modes. Stochastic gravitational wave background and its possible determination. Future prospects.

- Introduction to Cosmology (second edition). Barbara Ryden. Cambridge University press.
- Modern Cosmology. Scott Dodelson. Academic Press.
- Structure Formation in the Universe. T. Padmanabhan, University of Cambridge.
- Cosmology. Nicola Vittorio. CRC press.

The lectures will be two hours each and will take place twice a week. In the first part of the lecture a brief summary of the previous lessons will take place. The last ten minutes will be dedicated to possible questions and in-depth analysis. All lectures will then be made available in .pdf format on the teacher's website.

It is not mandatory to attend all the lectures in order to sustain the final exam.

The exam is oral only and is divided into two parts. In the first part the student presents a topic of his choice taken from the program. In the second one, questions will be asked about the rest of the program.