Precision Cosmology and Astrophysics with CMB Secondaries

University Of Pennsylvania, Philadelphia PA

Investigators

Abstract

The distribution of dark matter and its evolution over cosmic time contain a wealth of information on fundamental physics. The team of scientists led by the University of Pennsylvania will use new high-resolution data from the NSF-funded Atacama Cosmology Telescope (ACT) to map out dark matter through the way its gravity bends light from the early universe. This cosmic microwave background (CMB) lensing signal will be measured at high precision with a novel pipeline that combines ACT data, Planck satellite data and neutral hydrogen maps of the Milky Way, with the latter two allowing clean separation of contaminating signals. The high fidelity of the mass maps produced will allow for a measurement of the masses of neutrinos, the least understood particles in our universe. This work will be carried out by two graduate students who will receive advanced training in data analysis and statistical methods in cosmology. The project will result in a library of resources for astronomical data analysis aimed at the undergraduate level, as well as material for a course on Python for data science. The project will also aid in public outreach efforts through software applications that provide interactive Virtual Reality visualizations of dark matter and gas maps. This project is timely since current measurements suggest that the growth of structure in the high-redshift and low-redshift universe are not perfectly concordant. This project will obtain a precise percent-level measurement of the amplitude of matter fluctuations that will help distinguish between possible new physics resolutions to this anomaly. As a secondary objective, the team will produce maps of ionized gas pressure measured through the thermal Sunyaev-Zeldovich (SZ) effect through a careful foreground-cleaning procedure that uses a novel combination of millimeter-wave and 21-cm line data. Public release of the resulting CMB lensing mass maps and tSZ gas pressure maps will aid a variety of additional astrophysical and cosmological goals that include searches for primordial non-Gaussianity, primordial gravitational waves as well as studies of galaxy formation and the non-linear Universe. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.