
Course unit
RELATIVISTIC ASTROPHYSICS
SCP7081738, A.A. 2017/18
Information concerning the students who enrolled in A.Y. 2017/18
ECTS: details
Type 
ScientificDisciplinary Sector 
Credits allocated 
Core courses 
FIS/05 
Astronomy and Astrophysics 
6.0 
Mode of delivery (when and how)
Period 
Second semester 
Year 
1st Year 
Teaching method 
frontal 
Organisation of didactics
Type of hours 
Credits 
Hours of teaching 
Hours of Individual study 
Shifts 
Lecture 
6.0 
48 
102.0 
No turn 
Start of activities 
26/02/2018 
End of activities 
01/06/2018 
Prerequisites:

Classical electrodynamics, special relativity, general astronomy and astrophysics 
Target skills and knowledge:

The course aims at providing the student with an updated view of theory and observations of Galactic compact Xray sources 
Examination methods:

Oral examination 
Assessment criteria:

The oral examination aims at verifying to which extent the student knows the basic issues in relativistic astrophysics and his/her capacity of working with them. 
Course unit contents:

Compact objects. Late stages of stellar evolution, corecollapse supernovae. White dwarfs, neutron stars and black holes.
General relativity. The vacuum Schwarzschild solution and its properties. Geodesic motion in the Schwarzschild spacetime. Interior Schwarzschild solution, hydrostatic equilibrium configurations, the TolmanOppenheimerVolkoff equation. The Kerr solution (basics).
Degenerate systems. Quantum statistics (brief overview). Equation of state for a completely degenerate gas; the nonrelativistic and ultrarelativistic limits. The Chandrasekhar mass.
Matterradiation interaction. The radiation field. Emission, absorption and scattering. The radiative transfer equation. Optical depth. Simple solutions to the transfer equation: radiative diffusion and free streaming. Radiative processes: electron scattering and freefree. The Eddington limit.
Accretion onto compact objects. Spherical accretion, the BondiHoyle solution. Compact objects in bynary systems. The Roche lobe geometry. Wind and Roche lobefed accretion. Accretion discs. The standard disc model (alphadisc). Radiation spectrum from an alphadisc.
Neutron stars. Magnetic field and rotation. Magnetorotational braking and the period evolution. Estimate of the magnetic field and of the age from the period and the period derivative. The PPdot diagram. Magnetosphere, light cylinder. GoldreichJulian currents. The Alfven radius, column accretion onto magnetized neutron stars. Internal structure of a neutron star. Neutronization. Neutron star cooling. Neutrino cooling, URCA and modified URCA. Radiative cooling. Cooling curves. 
Planned learning activities and teaching methods:

Classrooms with worked exercises and examples 
Textbooks (and optional supplementary readings) 

Nobili, L., Astrofisica Relativistica. Padova: CLEUP, 2000.

Frank, J., King, A.R., Raine, D.J., Accretion power in astrophysics. Cambridge: Cambridge University Press, 2002.

Rybicki, G.B, Lightman, A.P., Radiative processes in astrophysics. New York: Wiley, 1985.


