Astrophysics and General Relativity

Astronomy and Astrophysics

Observational extragalactic astronomy

Yicheng Guo’s research focuses on how galaxies, such as our own Milky Way, were formed and evolved from small, irregular blobs in the early universe into today’s massive systems with diverse morphology. He is particularly interested in how star formation activity is turned on and off in galaxies. He is now using deep extragalactic surveys taken by the Hubble Space Telescopes to measure the mass, star-formation rate, metal abundance, and morphology of distant low-mass galaxies, which are believed to be the progenitors of today's Milky Way-like galaxies.

Theoretical studies of the interstellar medium

Aigen Li’s main research interests are the theoretical studies of the interstellar medium (with a focus on interstellar grains), the formation and evolution of stars and planetary systems (with a focus on protoplanetary dust disks around young stars, debris disks around main sequence stars, and dust envelopes around evolved stars), comets, and the infrared emission properties of galaxies.

Stellar evolution, astromineralogy and dust

Angela Speck is an infrared (IR) astronomer with broad experience including stellar evolution, astromineralogy and dust around evolved stars, galactic chemical evolution, meteoritics and the optical properties of materials. She has experience of data reduction for space-based telescopes from working with ISO data. Her primary focus is circumstellar dust, which pertains to basic questions of galactic processes and the origin of interstellar dust.

Galaxy formation and evolution

Haojing Yan is an observational astronomer who has a broad interest in galaxy formation and evolution, and is an active user of a variety of ground-based and space-based telescopes and their archives. Currently Haojing is largely focused on searching for and understanding galaxies in the early universe when it was only less than ~ 1 billion years after the Big Bang (or in other words, ~ 13 billion years ago), and on investigating the mass assembly history of galaxies over cosmic time. He has been leading a large program, “Hubble Infrared Pure Parallel Imaging Extragalactic Survey” (HIPPIES), using the data obtained by the Hubble Space Telescope. He has been deeply involved in a number of other space-based survey programs, such as the “Great Observatories Origins Deep Survey” (GOODS) and the “Spitzer Extended Deep Survey” (SEDS), and most recently the “Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey” (CANDELS).

Cosmology and General Relativity

Gravity and General Relativity

Prof. Sergei Kopeikin’s primary area of expertise is theoretical physics and astrophysics with emphasis to Einstein’s general relativity and gravitational physics. His research is closely related to experimental testing of general relativity and other alternative theories of gravity. He works in solving the Einstein and Maxwell equations in various astrophysical situations in order to make theoretical predictions of new relativistic effects for their subsequent testing by making use of high-precision observational techniques. These techniques include but are not limited to pulsar timing, very-long baseline interferometry, satellite and lunar laser ranging, atomic clocks, gravitational wave detectors, gravity-gradient meters, etc.His research is also directly related to the precise metrology of space and time in the solar system. Modern celestial ephemerides (developed in NASA JPL and other space navigation centers) include the results of his studies of post-Newtonian equations of motion, relativistic reference frames and time scales in the solar system which have been published in a textbook “Relativistic Celestial Mechanics in the Solar System” (Wiley-VCH: Berlin, 2011)His current research focuses on finding a theoretical explanation of various astrometric anomalies like the Pioneer anomaly, flyby anomaly, etc., which were discovered in motion of planets and deep space probes. He is also working on development of relativistic celestial mechanics in conformal spacetime of expanding universe. The ultimate goal of this research is building up a theory of generation, propagation and detection of gravitational waves coming to us from the epoch of Big Bang.