Astrophysics Faculty

Elena Aprile ("Laurea" in Physics, 1977 University of Naples, Italy; Ph.D. 1983, University of Geneva, Switzerland) is an experimental high energy astrophysicist with interests in cosmic sources emitting at MeV energies. She has contributed to the field with the development of a novel Compton telescope based on a liquid xenon time projection chamber. She is the Principal Investigator of the Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT), the first instrument using a LXeTPC for balloon-borne observations of the MeV gamma-ray sky. Aprile is also the Principal Investigator of the NSF sponsored XENON research project to develop a large underground liquid xenon experiment for the direct detection of dark matter WIMPs. The present XENON collaboration includes investigators at Columbia, Princeton, Brown and Rice Universities and at LLNL.

Andrei M. Beloborodov (M.Sc. Phystech, Moscow 1991; Ph.D. Lebedev Physical Institute, Moscow 1995) is a theoretical astrophysicist. He specializes in high energy phenomena in the Universe: X-ray binaries, active galactic nuclei, and cosmological gamma-ray bursts. His major interests include the physics of black holes and neutron stars, the mechanism of relativistic explosions, and the related radiative processes.

Charles J. Hailey (B.A. Cornell 1977, Ph.D. Columbia 1983) is an experimental high energy astrophysicist. His primary interest is the development of high resolution, grazing incidence gamma-ray telescopes for balloon and satellite-borne experiments. He is the Principal Investigator of one NASA project to develop such telescopes and a Co-Investigator of another. He is also doing observational astrophysics, particularly on neutron stars and galaxy clusters.

Lam Hui (B.A. Berkeley 1990; Ph.D. MIT 1996) is a theoretical astrophysicist specializing in cosmology. He has contributed to a variety of fields including the study of the Lyman-alpha forest, the thermal properties of the intergalactic medium, large scale structure, weak gravitational lensing, dark matter candidates, inflation, and extra-solar planetary transits. He is currently studying the implications of recent observations of high redshift quasar spectra for the reionization history of the universe, as well as the impact of short distance physics on inflationary fluctuations.

Brian Humensky (B.S. Carnegie Mellon 1996; Ph.D. Princeton, 2003) works in experimental particle physics. His research focuses on understanding the origins and acceleration mechanisms of cosmic rays and indirect searches for dark matter. He is currently focused on the VERITAS and CTA projects, which are ground-based gamma-ray observatories for gamma rays with energies above 100 GeV.

Bradley Johnson (B.S.Bethel College, 1996; Ph.D. University of Minnesota, 2004) is an experimental cosmologist.  His current projects include: LEKIDs, SKIP, SKILSS/GLP, CalSat, EBEX and PIPER.

Szabolcs Marka (Diploma 1993, Kossuth Lajos University (Hungary) Ph.D. 1999, Vanderbilt University) is an Experimental Astrophysicist. His focus is on the effort to directly detect gravitational waves of cosmic origin, which will allow us to study cosmic processes and objects unreachable through conventional methods based on electromagnetic observations. He is presently researching astrophysical trigger based data analysis and essential development/diagnostic projects aimed towards enhancing the astrophysical reach and reliability of the Laser Interferometer Gravitational-wave Observatory (LIGO).

Brian Metzger (B.S. University of Iowa, 2003; Ph.D. UC Berkeley, 2009) is a theoretical astrophysicist.  His main interests are topics in high energy astrophysics and time domain astronomy, including supernovae, gamma-ray bursts, accretion disks, compact objects, electromagnetic counterparts to gravitational wave sources, and nucleosynthesis (astrophysical origin of the elements).

Amber D. Miller (B.A. Berkeley 1995; Ph.D. Princeton 2000) is an experimental cosmologist. Her work concentrates on measuring and understanding both the primary and secondary anisotropies in the Cosmic Microwave Background (CMB). Miller's thesis research resulted in the first firm evidence of a flat universe from a single CMB anisotropy measurement. She is currently working on designing the receivers for a new telescope for surveying and imaging the Sunyaev-Zel'dovich effect in clusters of galaxies as another way to probe conditions in the early universe.

Reshmi Mukherjee (B.S. Calcutta 1986, M.A. Columbia 1989, Ph.D. Columbia 1993) (Barnard College) is an experimental astrophysicist concentrating on gamma-ray observations of active galactic nuclei and other sources. She is currently collaborating on the STACEE and VERITAS experiments, which are ground-based atmospheric Cherenkov detectors designed to measure high energy gamma-rays from astrophysical sources in the GeV-TeV energy range.

Malvin Ruderman (A.B. Columbia 1945, PhD Caltech 1951 ) works mainly in theoretical astrophysics. He has done pioneering research in collapsed stellar objects, especially neutron star structure and phenomena (birth, crusts, interior quantum fluids, spin-period jumps, magnetic field evolution, cooling). His recent work has emphasized understanding the various kinds of radiation emitted by such objects (radio and gamma-ray emission from pulsars, neutrinos, particle accelerators powered by neutron star spin, sources of cosmic gamma-ray bursts).