Cosmic Star Formation History and Galaxy Evolution
In my PhD thesis I study high-redshift galaxies using multiwavelength data in the Hubble Deep Field-North (HDFN).
Recent submillimeter and far-infrared studies have shown that most of the star formation at high redshifts is hidden by dust. This hidden star formation is invisible to optical observations and can only be picked up in the far-infrared, submillimeter, and radio. To understand how the universe turned diffuse gas into stars (and visible galaxies) we have to take dust-hidden star formation into account and we have to perform multiwavelength observations.
We carried out multi-wavelength, ultradeep imaging surveys in the HDFN using telescopes on Mauna Kea. The primary observations used in my PhD thesis include optical imaging with the 8m Subaru telescope, near-infrared imaging with the University of Hawaii 2.2m telescope, and submillimeter (0.85mm) imaging with the 15m James Clerk Maxwell Telescope. We also use the public data in the HDFN, including mid-infrared imaging with the Spitzer Space Telescope, optical spectroscopy with the 10m Keck telescopes, and radio imaging with the Very Large Array. With these data, we successfully detect 50%-80% of the hidden star formation in the universe. This percentage is by far the highest among all similar studies and is an important milestone. Prior to this work in the last 10 years, all other groups could only detect 20%-30% of the hidden star formation. This greatly improves our knowledge about the cosmic star formation history and galaxy evolution.
Recently (2006 spring and summer) I am working on near-infrared imaging with 4m to 8m telescopes and submillimeter interferometry in the HDFN and several strong lensing clusters. I will leave Hawaii this fall and move to the NRAO in New Mexico. We will see what's going to happen there.
Collaborators: L. L. Cowie (UH), A. J. Barger (UW-Madison), E. M. Hu (UH), and P. Capak (Caltech).
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