96391 - ASTROPHYSICS OF GALAXIES

Learning outcomes

The course addresses in depth some fundamental topics of the astrophysics of galaxies, training the students to analyze and critically discuss papers relevant for the current research in the field. Starting from a dynamical description of the structure of galaxies, the course then examines the comparison between model and observed quantities, in particular acquired with recent observational campaigns; the evidence for dark matter, extended and in the form of central massive black holes; the properties of the hot interstellar medium; the physical origin of the main galaxy scaling laws.

Course contents

The aim of the course is a deep understanding of the structure of galaxies, especially of the "early" morphological type. The study focusses on modeling, and on its use to interpret observational results and evidences. In a first part, some concepts of stellar dynamics are reconsidered, and the Jeans equations are derived, as a fundamental tool for the description of the stellar orbital properties and the mass distribution. The Jeans equations are then used in a number of applications, as the "detection" of dark mass components, and the relation between stellar orbital properties and shape. In a second part, the modeling is used to reproduce observed morphological and kinematical properties, with a particular attention to a proper comparison between observed and theoretical quantities. A few research papers are considered in depth, as representative of consolidated results and of currently debated subjects. In summary, the main investigated topics are the following:
1) the structure of the galaxies and of their different components; 2) the presence of dark matter: discovery and measurements; 3) the central supermassive black holes: discovery, measurement of their mass, effects on the host galaxy; 4) physical understanding of a few important scaling laws of galaxies, involving correlations between their structural/morphological/dynamical properties; 5) the stellar population in the scaling laws: roles of the IMF, age, metal abundance; 6) the relationship between the hot gas component and the stellar and dark mass components.

 

The official repository platform of the teaching material (virtuale.unibo.it), in the part dedicated to this course, contains a detailed list of all the topics included in the program, together with the bibliographic reference where each topic is found.

 

Readings/Bibliography

Fundamental textbooks as reference for many topics are the following:

Binney, Tremaine: Galactic Dynamics, Princeton University Press, 1987 (2008, 2nd edition)

Binney, Merrifield: Galactic Astronomy, Princeton University Press, 1998

Greggio, Renzini: Stellar Populations. A user guide from low to high
redshift, Wiley, 2011

Ciotti, L.: Introduction to Stellar Dynamics. Cambridge University Press, 2021

In addition, research papers on various subjects will be used and indicated during the lessons. These are also part of the necessary readings to complete the preparation to the exam.

The official repository platform of the teaching material (virtuale.unibo.it), in the part dedicated to this course, contains a detailed list of the Sections of the above textbooks that are needed for the preparation to the exam; all papers mentioned and discussed during the lessons are also given in the Virtuale repository and available for download. A copy of the slides used for the lessons is available on the repository.

 

Teaching methods

Oral lessons.

Assessment methods

The assessment method consists in an oral examination, that in general lasts for 45 minutes. The student can start with a topic of his/her choice taken from the syllabus (the detailed program with references available on Virtuale). Questions can be made then on each part of the program. The aim of the exam is to test the deep understanding of the chosen topic, the ability to put it in its astrophysical context, and a broader, more general knowledge of all the arguments of the course.

The evaluation is graduated as follows: if the knowledge demonstrated, even if incomplete, reveals a sufficient general preparation, the final grade ranges from 18 to 25 (depending on the clarity of exposition, ability to formalize the mathematical aspects); if the answers are complete and comprehensive, and demonstrate full mastery of the topic and independent reflection capability, the final grade ranges from 26 to 30L (depending on the level of the mentioned properties in the answers).

 

Teaching tools

Board and videoprojector.

Office hours

See the website of Silvia Pellegrini