Vahe Petrosian

How do things evolve in the universe? How are particles accelerated in the universe?

Professor Petrosian’s research covers many topics in the broad area of theoretical astrophysics and cosmology, with a strong focus on high-energy astrophysical processes.

Cosmological studies deal with global properties of the universe, where the main focus is the understanding of the evolution of the universe at high redshifts, through studies of the evolutions of population of sources such as galaxies and quasars or active galactic nuclei, gamma-ray bursts, using new statistical techniques developed in collaboration with Prof. B. Efron of the Department of Statistics. Another area of research is the use of gravitational lensing in measuring mass in the universe.

High-energy astrophysics research involves interpretation of non-thermal astronomical sources where particles are accelerated to very high energies and emit various kinds of radiation. These processes occur on many scales and in all sorts of objects: in the magnetosphere of planets, in the interplanetary space, during solar and stellar flares, in the accretion disks and jets around stellar-size and super-massive black holes, at centers of galaxies, in gamma-ray bursts, in supernovae, and in the intra-cluster medium of clusters of galaxies. Plasma physics processes common in all these sources for acceleration of particles and their radiative signature is the main focus of the research here.

Current areas of focus:

- Evolution of gamma-ray bursts and its implication for the early universe
- Evolution of blazars and quasars and their implications for super-massive black holes in the centers of galaxies
- Physics of particle acceleration in general magnetized astrophysical plasmas
- Development of new inversion techniques for determining the basic properties of acceleration mechanisms directly and non-parametrically from observations of high energy X-rays and gamma-rays from solar flares
- Acceleration of particles in clusters of galaxies and other diffuse media such as recently discovered Fermi bubbles around the center of our galaxy

Career History

• Member, Center of Space Science and Astrophysics & KIPAC
• Chair and Member of the Executive Committee, Astronomy Program 
• B.E.E., 1962, M.Sc. 1963, Ph.D. 1967, Cornell University 
• Research Fellow, California Institute of Technology, 1967-69 
• Stanford University, Assistant Professor, 1969-72 
• Associate Professor, 1973-79 
• Professor, 1980-present. 
• Alfred P. Sloan Fellow, 1972-74 
• Visiting Scientist at Institute of Astronomy, Cambridge, England, 1969 
• Visiting Scientists at Kitt Peak National Observatory, 1971, 1983, and 1998 
• Member, American Astronomical Society 
• Member, International Astronomical Union 

Former Students & Research Group Memebers