skip to content
ASCA Guest Observer Facility

ASCA Science Highlights: Active Galactic Nuclei

Follow the links to images and plots

There is a compact source with extraordinary energy output at the center (nucleus) of many galaxies: these are called Active Galactic Nuclei (AGN). Most scientists agree that these are supermassive black holes accreting matter from the nearby gas clouds and stars. X-rays are emitted from near the black hole itself, around which a disk of hot gas is thought to orbit. Strong iron emission line is formed in the disk; the observed energies of the emission line photons are spread around due to Doppler shifts and relativistic effects. With the energy resolution of ASCA, scientists have succeeded in studying the disk very near these supermassive black holes.

This page created by Dr. Koji Mukai (USRA) at the U.S. ASCA Guest Observer Facility.

This file was last modified on Monday, 28-May-2001 18:49:57 EDT
Curator: Michael Arida (SP Sys);
HEASARC Guest Observer Facility

If you have any questions concerning ASCA, visit our Feedback form.

This file was last modified on Monday, 28-May-2001 18:49:57 EDT

NASA Astrophysics

  • FAQ/Comments/Feedback
  • Education Resources
  • Download Adobe Acrobat
  • A service of the Astrophysics Science Division (ASD) at NASA/ GSFC

    ASCA Project Scientist: Dr. Nicholas E. White

    Responsible NASA Official: Phil Newman

    Privacy Policy and Important Notices.