AstroSat and X-ray/UV Emission from Active Galactic Nuclei

量子物理学・ナノサイエンス第259回セミナー

概要

Astrosat is India’s first multi-wavelength space astronomy mission that carries four co-aligned scientific payloads (i) a Soft X-ray Telescope (SXT), (ii) three identical units of Large Area X-ray Proportional Counters (LAXPCs), (iii) a Cadmium-Zinc-Telluride Imager (CZTI), (iv) two units of Ultra-Violet Imaging Telescopes (UVITs). AstroSat also carries a scanning sky monitor (SSM). I will provide an overview of instruments onboard AstroSat, their capabilities, and some results. AstroSat's multiwavelength capability is well suited to study Active Galactic Nuclei (AGN) which are the most powerful, steadily emitting objects in the Universe. The key ingredients of the AGN central engines - the accretion disk and the hot corona, emit in the UV to X-ray bands. The broadband UV/X-ray emission thus provides an opportunity to study complex processes occurring near the SMBH. In the second part of the talk, I will discuss the X-ray/UV spectral and variability signatures and the progress made based on recent X-ray/UV observations with XMM-Newton, Swift, NuStar, etc. I will also discuss the role of AstroSat X-ray/UV observations in understanding the AGN central engines.