Multi-wavelength studies of Active Galactic Nuclei
Abstract
Accretion onto supermassive black holes in Active Galactic Nuclei (AGN) produces vast amounts of energy over optical, UV and X-ray wavelengths from an accretion disc and corona; this primary emission may then be reprocessed by a dusty torus surrounding the central engine, giving rise to infrared emission and a number of AGN also exhibit radio emission from jets. Multi-wavelength studies are therefore key in understanding how AGN work, and help us in disentangling the diverse processes that are responsible for the emission we see. The rapid variability of the higher energy optical--to--X-ray emission indicates that it emerges from very close to the black hole, thereby offering a probe of the innermost regions of the accretion flow. The energy output of an AGN can exert significant influence on its immediate and distant surroundings, and in order to obtain this energy budget due to accretion at a given epoch, it is highly desirable to take simultaneous snapshots of AGN in optical, UV and X-ray bands. I will present a review of some key previous and current works on AGN spectral energy distributions (SEDs) using both simultaneous and non-simultaneous data and will discuss the intrinsic variability seen in individual AGN SEDs from one epoch to another. Finally, I will touch on how the capabilities of ASTROSAT will be well suited to extending such studies in future.
- Publication:
-
39th COSPAR Scientific Assembly
- Pub Date:
- July 2012
- Bibcode:
- 2012cosp...39.2062V