Project Title: Supermassive Black Holes: Life on the Edge

Project Advisor: Paul J. Green

Background: Quasars are extremely luminous galaxies whose cores are inhabited by supermassive blackholes accreting matter from the surrounding environment. The birth, growth and feeding of these black holes is tied into structure, galaxy, and star formation in the Universe. X-ray images are by far the most complete and efficient way to find quasars, and the Chandra Observatory is the most sensitive X-ray telescope ever, with the best spatial resolution, allowing quasar detection to high redshifts, and facilitating unambiguous counterpart identification in other wavebands.

Scientific Questions: When did black holes first form? How long do they live? Do active quasars cluster with galaxies, indicating environmentally-triggered feeding?

Scientific Methodology: Now that our X-ray and optical imaging survey is complete, we are emphasizing large sample studies using ChaMP's overlap with the SDSS. Simulations and detailed completeness estimates allow us to accurately characterize space density and luminosity function calculations out to high redshifts. We now have in place a novel "stacking" tool that allows us to co-add large samples of common but X-ray faint objects such as typical spiral galaxies in the nearby Universe. While many may be individually undetected, our stacking achieves enormous (many Msec) Chandra effective exposure times to characterize the luminosity distribution of the sample. We also need someone to work on studying the effect of galaxy environment on X-ray activity. This clustering analysis will test the interaction/triggering paradigm for supermassive black hole activity. The ground-breaking work already performed for the ChaMP has left a lot of "low-hanging fruit" for a capable student to pick!

Other links related to this project

• ChaMP public page
• Chandra X-ray Observatory