Black Holes
Black holes are inevitable given our understanding of astrophysics and general relativity. They can be simply describe by their mass, which sets a scale of length time and power, and their rate of spin which describes their geometry. Black holes are common remnants of the evolution of high mass stars and are occasionally born as Gamma Ray Bursts. They are also found in the nuclei of most normal galaxies with masses in the range millions to billions times that of the sun. They are responsible for the brightest X-ray binary stars and the powerful quasars that can be seen across the universe and from when the universe was a few percent of its present age. Most black holes "shine" by accreting gas through an orbiting accretion disk. The gas heats and radiates and causes nearby gas to glow. The gas can also concentrate magnetic field around the black hole which can extract its rotational energy and lead to the production of outflowing, relativistic jets. My interests in this area are currently focused on computing the details of the mechanism responsible for the production of jets on understanding what happens when stars are captured from circular orbits and in proposing new approaches to detecting gravitational radiation when binary black holes merge.
Evolution of stars in circular, equatorial orbits around a spinning, massive black hole (Dai & Blandford 2012).
Some Recent Papers
- General relativistic magnetohydrodynamic simulations of magnetically choked accretion flows around black holes
- Roche accretion of stars close to massive black hole
- Alignment of Magnetized Accretion Disks and Relativistic Jets with Spinning Black Holes