96398 - THE INTERSTELLAR MEDIUM

Learning outcomes

At the end of the course, the student has a detailed knowledge of the observational and physical properties of the interstellar medium (ISM). In particular, the student acquires knowledge of the main constituents of the ISM (ionized, atomic, and molecular gas; dust; magnetic fields; cosmic rays; EM radiation), the different environments in which these are encountered (the 2- and 3-phase models of the ISM) and the physical processes that govern them. In addition, the student will acquire some knowledge about the central role played by the ISM in the evolution of galaxies and AGN across the cosmic time.

Course contents

- Introduction to the course.
- The different components of the interstellar medium.
- Fundamental concepts: Electronic, vibrational and molecular transitions. Statistical equilibrium equation, level populations and line formation, radiative transfer equation. Line ratios as diagnostics for density, temperature and abundance.
- The phases of the ISM
- Interstellar dust: Extinction curves and reddening. Definitions of absorption, scattering and extinction cross sections. Constituents of interstellar dust. PAHs. Radiative heating and cooling of dust grains. Infrared emission.
- Models for dust formation, evolution and destruction.
- PDRs, XDRs, and the extragalactic ISM: Formation and destruction of H2. Self-shielding. PDRs and XDRs.
- The cosmic evolution of the ISM as a function of the redshift z   and its connection to the star-formation rate  and accretion rate density evolution.
- The Alma window

Readings/Bibliography

The final exam can be prepared using the notes taken during the lessons. Articles to focus on specific topics, will be also indicated during the Course.

Additional text books useful for further detailed study are:

'Physics of the interstellar and intergalactic medium', Draine

'The physics and chemistry of the interstellar medium', Tielens

Teaching methods

The course is made of 6 CFU, corresponding to 48 hours of front lectures. These are made with the support of power-point presentations and at the blackboard.

The course will focus on both the theoretical and the observational aspects of the ISM.

Key and updated observational aspects of the ISM will be presented with the use of articles/reviews and thanks to  few lessons given by  colleagues of INAF-OAS on specific topics.

Assessment methods

The final examination aims at verifying and evaluating the acquisition of the teaching goals. It consist in an oral assessment, usually lasting 40-45min.

The exam will start with a topic chosen by the student.

Teaching tools

Lectures are supported by power-point presentations, which are updated and made available to the students every year on the dedicates web site "Virtuale uniBO" of the Bologna University

Office hours

See the website of Francesca Pozzi