27200 - Active Galaxies

Learning outcomes

At the end of the course, the student has a detailed knowledge of the observational and physical properties of Active Galaxies in the various bands of the electromagnetic spectrum. In particular, the student acquires knowledge of galaxies with intense star formation, of active galactic nuclei, and the connection between accretion and star formation in the host galaxies. The student is also able to derive physical parameters from observational data for the different classes of active galaxies.

Course contents

Main topics: AGN physics and classification - AGN evolution - The first AGN in the Universe

• Introduction to the course.

• Brief historical perspective on AGN.
  

• Pills on thermal and non-thermal processes.
  

• The black hole paradigm. 'Stardard' and efficient Shakura-Sunyaev disks vs. inefficient ADAF solutions. Slim-disks and their possible applications to growing BHs. The 'big' AGN family and unification models.
  

• Main components of AGN: multi-band continuum emission and broad/narrow line region emission. Physical processes in AGN gas and dust. Results from interferometry in the ALMA era.
  

• BH masses from reverberation studies and scaling relations.
  

• Jetted vs. not-jetted AGN. Emission processes, observational features, spectral energy distributions, and blazar sequence. Prospects for the Cerenkov Telescope Array.
  

• X-ray properties of AGN. The accretion disk-corona interplay. The iron K_alpha emission as a probe of the AGN internal structure and properties.
  

• A close look at the innermost regions of AGN: EHT and GRAVITY results.
  

• Feedback from AGN. The impact of winds and outflows on small and large scales in setting the M-sigma relation: current multi-wavelength studies.
  

• AGN vs. X-ray binaries: the properties of accretion on different scales, and the fundamental plane for accretion.
  

• Low-efficiency super-massive black holes: the special case of SgrA*.
  

• Flux and spectral variability in AGN. The intriguing case of changing-look AGN. Transient phenomena and accretion (e.g., TDEs) in AGN.
  

• Formation and evolution of AGN. X-ray surveys and X-ray background synthesis models. Missing pieces in the current framework?
  

• Obscured AGN across cosmic time: selection, multi-wavelength properties, and evolution of the obscuration.
  

• Quasars as cosmological probes.
  

• Host galaxies of AGN. Black hole accretion-rate density vs. star-formation rate density. The AGN-starburst connection.
  

• The environment of AGN and the role of mergers in triggering nuclear activity. The quest for dual/binary AGN in the era of gravitational waves.
  

• The realm of high-redshift AGN and theories on seed black holes.

• The role of the host-galaxy ISM in obscuring nuclear activity at high redshift. Perspectives from next-generation facilities.
  

• What we don't know (yet).
  

• Gamma-ray bursts: observations, physics and models. Connection with GWs.
  

Readings/Bibliography

• Hale Bradt: "Astrophysics Processes: The Physics Of Astronomical Phenomena", Cambridge University Press

• George B. Rybicky, Alan P. Lightman: "Radiative Processes in Astrophysics", Wiley

• Gabriele Ghisellini: "Radiative processes in high energy astrophysics", Springer, Lecture Notes in Physics 873

• Bradley M. Peterson: "An introduction to Active Galactic Nuclei", Cambridge University Press
  

• J. Frank, A. King & D. Raine: "Accretion Power in Astrophysics", Cambridge University Press

• Frederick D. Seward, Philip A. Charles: "Exploring the X-ray Universe", Cambridge University Press

• Hagai Netzer: "The Physics and Evolution of Active Galactic Nuclei", Cambridge University Press

• Volker Beckmann, Chris Shrader: "Active Galactic Nuclei", Wiley-VCH

• Haardt F., Gorini V., Moschella U., Treves A., Colpi M.:
  "Astrophysical Black Holes", Springer, Lecture Notes in Physics, 905

• Falanga M., Belloni T., Casella P., Gilfanov M., Jonker P., King A.: "The Physics of Accretion onto Black Holes", Springer, Space Sciences Series
  of ISSI
  

• Articoli di approfondimento di letteratura.

Teaching methods

In the lessons, the classification of Active Galaxies will be discusses along with their multi-wavelength properties and emission processes. This will be carried out using textbooks, papers and reviews.

Assessment methods

Students' knowledge in the field of Active Galaxies will be based on an oral exam, starting with a topic chosen by the student, followed by questions on topics covered during the course. The student is required to link, in the most appropriate way, the various topics discussed during the course, and to be able to discuss in a critical way the main topics and open issues in modern astrophysics in the field of Active Galaxies. Besides, the student should show skiils in deriving physical quantities.

Teaching tools

Powerpoint presentations (available on the personal webpage and at IoL) and dashboard.

Office hours

See the website of Cristian Vignali