Black Holes and Quasars – University of Copenhagen

DARK > Research > Black Holes and Quasars

This illustration shows a supermassive black hole in the nearby spiral galaxy NGC 1365. (NASA 2013)

Black Holes and Quasars

Black holes are extreme concentrations of matter with a gravitational pull that not even light escapes. Supermassive black holes, millions to billions of times the solar mass, formed in the early Universe at the focal points of coalescing matter that evolved into galaxies.

Supermassive black holes are expected to be present at the hearts of all galaxies, quiescent or active. A tight relationship between the black hole mass and the velocity dispersion of the stellar bulge of the galaxy is observed in the local Universe. This suggests that black hole formation and evolution plays an important role for the formation and evolution of the galaxies.

Active Galactic Nuclei

Radio galaxy 3C296; radio/optical superposition (NRAO/AUI 1999)

Active galactic nuclei (AGN) are galaxies that have very energetic central regions, due to the presence of a supermassive black hole that feasts on gas that falls from the galaxy into the very center of the galaxy. One type of AGN are quasars.

The infall of matter onto the supermassive black hole can result in very hot regions where huge energies are released, powering quasars. We can study the effects of black holes on their surroundings. These include powerful jets of electrons that travel huge distances, many thousands of light years from the centres of the galaxies.

Current work by researchers at DARK:

  • Using Active Galactic Nuclei as a cosmological distance tool
  • Determining masses of supermassive black holes
  • Black hole accretion properties
  • Multi-wavelength observations of AGN and AGN host galaxies
  • AGN fuelling processes
  • Techniques: therory & observation, including interferometry, gravitational lensing, radio waves

Active grant-funded projects:

  • Improving Supermassive Black Holes as Cosmic Probes (PI, Vestergaard)