Science Deliverables

16,000 X-Ray sources

This proposal will identify up to 16,000 active galaxies in three surveys (called GOODS, COSMOS, and Stripe 82X), which have complementary combinations of depth (sensitivity) and area on the sky. The active galaxies will be identified by the amount of X-ray light they emit.

Redshifts & Distances

Their distances will be measured using optical and infrared spectroscopic observations at large telescopes to determine the redshift (i.e., the wavelength shift of atomic emission or absorption lines) of a large fraction of the active galaxies. For the rest, the investigators will estimate redshifts by analyzing the total infrared, optical, and ultraviolet light that they emit.


Catalogs listing the X-ray, infrared, and optical brightness of each active galaxy will be made publicly available, along with their redshifts, so that anyone can mine the data to answer other astronomical questions.

Spectral Energy Distributions

In this project, the investigators will analyze the overall spectral energy distribution of each active galaxy to deduce its dust and gas content. For selected subsets of data, the investigators will measure key characteristics like black hole mass, luminosity, amount of dust and gas (important for understanding whether any light is occluded), black hole growth rate, and the number of other galaxies near each active galaxy.

Evolution of Supermassive Black Holes

The investigators will combine these measurements to model the growth of black holes over time, constrained by the data acquired. The investigators will also search for evidence of the interplay between black hole growth at the center of the active galaxy and star formation throughout the active galaxy; this will be most apparent in massive galaxies, like our own Milky Way.