Black Hole Feedback and Galaxy Formation

University Of Nevada Las Vegas, Las Vegas NV

Investigators

Abstract

Dr. Nagamine will combine his hydrodynamic simulations of newly-forming galaxies in regions hundreds of light years across with those of co-investigator Dr. Proga, which follow disk accretion within the central few light years around a black hole. To bridge the 8 orders of magnitude in scale between them, these calculations will be linked by runs at intermediate scale using a 'zoom-in' technique of successively re-simulating an interesting volume at much higher resolution. Black holes are included in the largest-scale simulations both as sink particles that grow in mass by merging and by accreting gas, and as sources of energy, momentum and ultraviolet radiation. Both 'sink' and 'source' terms will be represented by approximate formulas; the model predictions will be compared with observations of the intergalactic gas, and the numbers of active galactic nuclei seen at each redshift. As a novel aspect, the PI will calculate how the ultraviolet radiation of young stars and active nuclei propagates out into the intergalactic gas. Galaxy-scale simulations will be used to find how fast gas will flow into the inner galaxy. This provides an outer boundary condition for the last calculation, which describes the accretion disk around the central black hole. At this last stage, the group can calculate how much radiation and momentum the black hole should inject back into the gas of the galaxy. These will be the first calculations of how a black hole feeds and shines, when it is in the center of a galaxy that is itself merging with others according to cosmological predictions. A graduate student and a postdoctoral fellow will be trained by their involvement in the research. Undergraduate students will participate through an NSF-funded summer Research Experiences for Undergraduates program. Dr. Nagamine will help to plan a new public planetarium on the UNLV campus, and will design cosmology exhibits for it. The team will generate images and movies made from the simulations, for use in public outreach; they aim to produce visualizations of sufficient quality for an IMAX movie. Both investigators will continue to give public lectures in a series organized by UNLV.