This group will investigate how the light of newly-forming galaxies and the active nuclei of galaxies propagates through the intergalactic gas. They focus attention on a period that ended about a billion years into cosmic history, when the neutral intergalactic gas was ionized by the ultraviolet light of galaxies. To calculate how gas and dark matter came together to make the galaxies, the group will use hydrodynamic simulations. They will develop and refine their calculations to predict when a galaxy should form stars, or develop an active nucleus. Then, the photons emerging from the galaxy will be tracked using Dr. Li's 3-dimensional radiative-transfer code. That code will be improved to handle Lyman-alpha photons, ionization, and the effect of very small dust grains. The group will produce large mock catalogs of high-redshift galaxies and quasars that describe their emission from X-ray to millimeter wavelengths, and include the hydrogen lines at 21cm and Lyman alpha.
Two graduate students will be trained by participating in the research. The new radiative-transfer code, and the mock catalogs, will be made available to the astronomical community. Those catalogs summarize the predictions of our theories about how galaxies grow. This group and others will test those theories by comparing the catalogs with what is seen in current and planned deep surveys of distant galaxies. Both Dr. Li and Dr. Abel work at institutions with strong records in public outreach, and this project will yield attractive still images and movies to illustrate current ideas about galaxy formation.
