welcome

Currently I am a Chandra Fellow (now renamed as Einstein Fellow) at Harvard-Smithsonian Center for Astrophysics, trying to locate black holes, stars, and dust in the Milky Way for future space travels (which I seriously think is inevitable to avoid human extinction due to overpopulation on the earth).
Best thing for my job? -- I can go atop high mountains to look at twinkling stars in absence of any city light, with telescopes a hundred times larger than the 2-inch telescope I made myself in high school.
My Research Interests
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  1. The nature of ultraluminous X-ray sources, including their X-ray spectroscopic and timing properties, their optical counterparts and environments, and most importantly, the dynamical mass measurements to determine whether they are the long sought intermediate mass black holes.
     
  2. The physics and population of stellar mass black holes. These include measuring the black hole spin, searching for over-massive stellar black holes in nearby galaxies, and searching for black hole X-ray binaries in the Milky Way.
     
  3. The three dimensional structure of the Milky Way in terms of the stellar, gaseous and dust contents. Now I am using SDSS/2MASS to construct the 3D extinction/dust map and 3D stellar map, properly corrected for extinction.
Selected papers
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  1. Hubble reveals a 6-day period for an ultraluminous X-ray source in NGC1313
    Liu, Jifeng, Bregman, J. & McClintock, J.   |link|  ApJL, 690, 39L (2009)
  2. Measurement of the spin parameter of a stellar-mass black hole in the nearby spiral galaxy M 33
    Liu, Jifeng, McClintock, J., Narayan, R., Davis, S. & Orosz, J.   |link|  ApJL, 679, 37L (Liu 2008b)
  3. The Optical Counterpart of an Ultra-Luminous X-ray Source in M81
    Liu, Jifeng, Bregman, J., and Seitzer, P.   |link|  ApJL, 580, 31 (Liu2002a)