Special Session SS12  30 June 2022

The inner parsec of AGN: accretion, winds & clouds

News: INFORMATION FOR SPEAKERS:

  • Review talks: speaking time is 16' + 4'
  • Contributed talks: speaking time is 8' + 2'

Aims and scope

Active galactic nuclei (AGN) are powered by accretion onto supermassive black holes (SMBHs) and represent the most powerful, long-lived objects in the Universe. The X-ray/UV/optical emission in AGN constitutes the bulk of their radiation output and originates from the innermost regions around the SMBH on scales less than 1 pc. The sub-parsec scale structure of an AGN is believed to comprise three main components: an accretion disk, a corona of hot electrons producing X-rays by Comptonization of optical/UV disk photons, and a region of high-velocity gas clouds predominantly in Keplerian motion (the broad line region, BLR). There is growing evidence that winds originating from the accretion disk (i.e. UFOs, BAL outflows) are another key ingredient of AGN as revealed by a wealth of X-ray and UV observations.

Recent results from optical/UV/X-ray spectroscopy and reverberation mapping campaigns of AGN revealed the presence of a very complex, often variable, mixture of emitting and absorbing gas components in the extreme environment close to the SMBH. The origin, geometry and kinematics of these gas flows are still yet to fully be discovered. The main goal of this Special Session is to provide a timely opportunity for capturing and discussing advances in our understanding of the following key subjects of AGN research :

  • Changes in the properties of the accretion disk/corona system at different Eddington ratios
  • Origin and multi-wavelength evolution of changing-look AGN
  • Properties of highly variable nuclear absorber(s)
  • Origin of the X-ray weakness phenomenon
  • Geometry, energetics and launching mechanisms of accretion disk winds
  • Structure and kinematics of the BLR

    • Programme

    The program consists of three sections, each dedicated to a mixture of observational results and theoretical modeling, and introduced by two invited review speakers, covering the following topics:

    • Section I "Disk and Corona properties at different accretion regimes"
    • Section II "AGN weather: winds & clouds"
    • Section III "New models, telescopes & strategies for probing the AGN innermost regions"

    Invited speakers

    • Section I: M. Giustini (Centro de Astrobiologia)
    • Section II: T. Waters (University of Nevada); A. Rankine (University of Cambridge)
    • Section III: G. Matt (University of Roma Tre)

    Scientific organisers

    • Erin Kara (Massachusetts Institute of Technology, USA)
    • Mariko Nomura (National Institute of Technology, Japan)
    • Enrico Piconcelli (Istituto Nazionale di Astrofisica, Italy) [Chair]
    • Paola Rodriguez Hidalgo (University of Washington Bothell, USA)
    • Francesco Tombesi (University of Rome Tor Vergata, Italy)

      • Contact

      enrico.piconcelli @ inaf.it

      Updated on Wed Jun 15 09:56:57 CEST 2022
    European Astronomical Society