Compact Objects

Imaging Black Holes" (Image credit: Avery Broderick, Avi Loeb)

Research Description

The study of compact stellar remnants—white dwarfs, neutron stars, black holes—and their larger cousins, supermassive black holes, is a major area of research in modern astrophysics. Conditions are extreme in the vicinity of these objects and lead to a variety of unusual phenomena such as high energy X-ray and gamma-ray radiation, high frequency oscillations, and relativistic jets. The objects are often extraordinarily luminous and affect their surroundings to a much greater extent than one might guess from their small sizes.

At the same time, compact objects are of interest in their own right. The density inside a neutron star is greater than nuclear density, and the magnetic field is far greater than anything we can generate on Earth. A black hole is even more extreme. Within classical physics, the density technically goes to infinity inside a singularity. In addition, everything in the vicinity of the black hole Event Horizon is ruled by strong gravitational effects associated with Einstein's General Theory of Relativity.

Faculty in the Astronomy Department carry out research in diverse topics in this field. A brief list includes:

  1. Measuring the masses and spins of stellar-mass and supermassive black holes.
  2. Verifying the reality of the mysterious Event Horizon.
  3. Studying accretion disks around white dwarfs, neutron stars and black holes, and investigating how these disks cause relativistic jets.
  4. Exploring the formation of neutron stars and stellar-mass black holes in supernova explosions, and the birth of supermassive black holes during galaxy formation.
  5. Investigating the extreme properties of quasars, blazars and other active galactic nuclei and the evolution of these populations as a function of cosmic time.
  6. Studying energy and momentum feedback from supermassive black holes and the enormous effect these have on galaxy evolution.
  7. Comparing and contrasting the supermassive black hole in the center of our Milky Way Galaxy with those in other galaxies.