Collaborative Research: Cross-correlation of WISE quasars with the Planck CMB lensing maps: A new probe of black holes and large-scale structure

University Of Wyoming, Laramie WY

Investigators

Abstract

A longstanding problem in astrophysics is to understand how galaxies form and develop throughout their lifetimes. Such understanding is necessary to uncover how our Universe evolved and to gain insight into the origin of our own Milky Way Galaxy. One important aspect of understanding galaxy formation and evolution is to study supermassive black holes (SMBHs) at the centers of galaxies and how these SMBHs are linked to their host galaxies. Another major question in astrophysics involves the concept of "dark matter," an unidentified type of matter believed to have the properties of gravitation but not to emit any light (hence, "dark"). Thereby addressing two major astrophysical problems, this project aims to link SMBHs to the dark matter structure of their host galaxies. All-sky surveys with the Wide-Field Infrared Survey Explorer (WISE) and Planck cosmic microwave background (CMB) satellite have now produced groundbreaking data sets, which are used together to obtain constraints on the evolution of structure in the Universe. WISE uncovered millions of the previously "hidden" obscured quasars, rapidly growing supermassive black holes that are shrouded in gas and dust and so are not detectable using traditional ground-based optical and near-IR techniques. Recently, Planck produced the most precise all-sky map to date of dark matter structures via the lensing of the CMB. This project will combine these data sets along with ground-based imaging and spectroscopy to obtain a uniquely powerful measurement of the link between rapidly growing black holes and their host dark matter structures by cross-correlating the density field of WISE-selected quasars with the CMB lensing convergence maps obtained from Planck. In addition, this project will use astronomy to build problem-solving intuition in students through order-of-magnitude (OOM) estimation, or "Fermi Problems." Building on successful OOM activities in introductory astronomy courses at Dartmouth College, the investigators will develop OOM exercises for use at the middle, high school, and undergraduate levels, in which real-world estimation problems are combined with more abstract questions based on astronomical concepts. The investigators will organize workshops in which teacher participants learn to incorporate OOM activities in their classrooms and help develop new OOM exercises. Both Dartmouth and the University of Wyoming are located in rural areas, and the investigators will focus on under-resourced schools. By developing OOM exercises and instructing teachers in implementing them in their classrooms, this project will serve to foster students' problem-solving intuition. These skills are particularly useful when applying scientific or mathematical thinking to real-world problems, and success in problem solving will help create enthusiasm and future opportunities for students in STEM. The exercises and teacher reference materials produced by this program will be disseminated to the wider educational community via the web, conferences, and publications, providing a resource for all interested instructors at multiple levels to incorporate OOM activities into their classrooms. This project will (1) produce the first all-sky measurement of quasar clustering bias using the WISE and Planck data, and (2) directly compare the halo masses of obscured and unobscured quasars, using wide-area deep optical imaging from the Dark Energy Survey (DES) and SDSS, and measure the evolution of those biases with redshift, using a technique independent of spatial clustering. This project will enable a significant step forward in our understanding of the cosmic evolution of black holes and their host halos, and will yield valuable tools for future studies with WISE, Planck, and upcoming ground-based surveys.