Probing Super-Massive Black Holes

Probing Super-Massive Black Holes

  • Active galactic nuclei and quasars fueled by accretion of matter onto massive black hole
  • Gravitational energy released and converted to radiation - particularly X-rays - as infalling matter nears black hole
  • X-rays produced nearest to event horizon
  • Relative to other wavelength observations, X-rays probe 100,000 times closer to black hole
  • Best suited to measure strong gravity effects and test General Relativity
  • What are Supermassive Black Holes?

    gravitationally collapsed objects that preclude escape from their surface

    ~ 100 million solar masses

    less than the solar system

    the nuclei of many galaxies, both active and dormant

    via the rapid motion of radiating matter tightly orbiting around the black hole as revealed by optical, radio and X-ray spectral line features, especially definitive with upcoming X-ray missions

    What is their origin?

    A problem:
    The mass characteristic of the earliest gravitationally bound "seed" objects is much too small.

    A plausible solution:
    initial radiationless rapid growth via the smothering accretion of amply available ambient matter, ended by a likely X-radiating phase of slower growth.

    An experiment:
    investigate the faintest individual sources of the presently unresolved residual cosmic X-ray background for evidence of a large new population signaling the birth of supermassive black hole galactic nuclei.

    Missions: AXAF, ASTRO-E, HTXS

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