I am a theoretical astrophysicist. Over the years, I have worked on the dynamics of globular clusters and galactic nuclei, interstellar scintillation, gamma-ray bursts, strong astrophysical shocks, star formation near quasars, planetesimal formation, angular-momentum transport in astronomical accretion disks, tidal effects in stars and gaseous planets, gravitational microlensing, and laboratory astrophysics. At present, I am … Continued
We are interested in astronomical instrumentation, adaptive optics, and high contrast imaging with applications for the detection of extra-solar planets.
We are focused on these three areas: (1) A new Lorentz-covariant nonlinear extension of classical electrodynamics was proposed. It uses only the electromagnetic degrees of freedom – Strong-Field Electrodynamics. This allowed us to calculate the first dissipative pulsar magnetosphere. (2) With Farrar, we proposed that ultra-high-energy cosmic rays can come from rare bright flares on … Continued
Our group studies the first luminous sources in the Universe, including both how they formed and evolved and their effects on their surroundings. We have shown that the most luminous of these sources are at least qualitatively similar to galaxies that we observe later in the Universe’s history, but very recent observations require that fainter … Continued
I am interested in using and developing high spatial resolution imaging techniques to (1) study star formation and (2) investigate the proposed massive black hole at the center of our Galaxy. Owing to turbulence in our atmosphere, the resolution of pictures obtained with traditional imaging techniques from large ground based telescopes is a factor of … Continued
I work on the evolution of galaxies and on cosmology. Current research topics: studies of massive galaxies at high-redshift, measuring dark matter using strong gravitational lensing, machine learning and AI for discovery in astronomical images, the physical origins of the Hubble sequence.
My research focuses on the cosmic “first light” – the epoch a few hundred million years after the big bang when the earliest generations of galaxies and quasars began to appear in the universe. In particular, I study the formation and evolution of quasars, powered by accretion to supermassive black holes, and how supermassive black … Continued
My group made measurements that established that the enigmatic Lyman alpha forest absorbers that permeate much of the early universe are much larger than originally suspected, which implied that most of the normal matter in the early Universe resided in the Lyman alpha. Our group puts severe limits on the amount of dark matter in … Continued
I study the cosmic microwave background (CMB), the 14 billion year old fossil light from the early Universe, to investigate the origin and evolution of the Universe. I am currently the director of the 10-meter South Pole Telescope, located 1 km from the geographic south pole. I have been developing the next generation ground-based CMB … Continued
I develop novel astronomical techniques to detect and characterize planets orbiting other stars. My group is currently focussed on identifying temperate rocky planets that pass in front of small nearby stars. Once identified, the atmospheres of such worlds can be probed with upcoming ground and space-based observatories to search for the molecules produced by life. … Continued