Elements of Astrophysics


course ID

kard9bz

Lecturer

CFU

6

Length

14 Weeks

Semester DD

First


Course details

1 - Introduction, the role of gravity; observational channels, fundamental scales and quantities; the electromagnetic channel: atmospheric transparency, emission processes; sfericity of planets and altitude of mountains.

2 - Virial Theorem, derivation, applications: internal temperature of the Sun. Fluid derivation. Discrete form, application to the Coma Cluster. Examples of plasmas in stars and galaxy clusters. Virial Theorem for the active galactic nuclei.

3 - Stars, characteristic time scales; production of thermonuclear energy, curve of the binding energy; p-p chain, Gamow peak; black body radiation; Thomson scattering, mean free path; L-M relation, spectral classification, Balmer and Lyman series, HR diagram; Eddington luminosity; CNO cycle, notes about sequence and post-sequence evolution, stellar populations.

4 - End states. Fermi gas, degeneration pressure; white dwarfs, mass-radius relation; brown dwarfs; Chandrasekhar limit mass; nutronization, neutron stars, Oppenheimer-Volkoff mass; pulsars; black holes, Schwarzschild radius.

5 - Hubble law, redshift; Einstein-deSitter model, Friedmann-Robertson-Walker models; Friedmann equations; Robertson-Walker metric; concordance model, dark matter, dark energy; cosmological redshift, redshift theorem; luminosity distance, look-back time.

6 - Galaxies; Milky Way, external galaxies; surface brightness; differential rotation, radial velocity, rotation curves; Dark Matter, WIMPs; disk galaxies, gas motion, rotation curves, Hubble sequence for galaxies; elliptical galaxies, surface brightness profiles, stellar velocities in galaxies; Tully-Fisher relation; Faber-Jackson relation.


7 - Active galactic nuclei and quasars: luminosity, spectrum, size; spectral energy distribution; emission limes; structure; variability; power source; Eddington limit; supermassive black holes, innermost stable circular orbit, gravitational redshift; accretion disk, bug blue bump; evidence of supermassive black holes; Galactic Center; echo mapping, structure of the broad line region; evolution, luminosity function; growth of the supermassive black holes. Practice: electromagnetic spectrum, black body; free fall time, Virial Theorem, form factor; computation of masses; main sequence, life times, spectral series; redshift, Hubble law, flux, luminosity, luminosity distance; Schwarzschild radius, Eddington luminosity, emission lines, variability.

Objectives

LEARNING OUTCOMES: Base concepts on the observational channels in the Universe, and on the astrophysical sources of electromagnetic radiation. Elementary notions on the role of the gravitational force in main systems of astrophysical and cosmological interest: normal and collapsed stars, stellar and supermassive black holes, quasars and active galactic nuclei, expansion of the Universe and Big Bang.

KNOWLEDGE AND UNDERSTANDING: - Base knowledge about stars, galaxies, active galactic nuclei, black holes, Universe. - Elementary knowledge on the role of gravity in such systems. - Elementary knowledge on the propagation of electromagnetic waves in an expanding Universe.

APPLYING KNOWLEDGE AND UNDERSTANDING: - To be able to estimate the main physical characteristic quantities of sources, masses, sizes, distances, luminosities, by the use of the appropriate physical relations.

MAKING JUDGEMENTS: - To be able to assess the reliability of a numerical result by comparing with the standard properties of the examined systems.

COMMUNICATION SKILLS: - To be able to present an elementary topic of astrophysics. - To have a knowledge of the English language sufficient to read and understand correctly a scientific text of astrophysics.