Understanding the origin of our Universe remains a primary quest of astrophysicists, and such studies of cosmology advance our mastery of fundamental physics, which in turn leads to technological advances that accelerate our nation's economy. This project focuses on deep maps of cosmic microwave background (CMB) polarization that offer tremendous opportunities for cosmology and fundamental physics. Most cosmologists believe that the entire observable Universe was spawned in a fraction of a second by the superluminal "inflation" of a subnuclear volume. Inflation produced a cosmic gravitational background (CGB) that may be detectable now via the faint signature imprinted in "B-mode" patterns of degree-scale CMB polarization. Their amplitude directly measures the energy scale of the inflationary Big Bang. Detecting the polarization signature of the CGB may be the most important goal in cosmology today. At arcminute scales CMB polarization traces gravitational lensing from the high redshift Universe, measuring early dark energy and neutrino mass. Where they overlap, such measurements will allow delensing of inflationary CGB searches, enabling better constraints of inflationary physics.
The BICEP/SPUD series of experiments operating from the South Pole have pursued a targeted strategy toward this important science goal. BICEP1 produced the best current published upper limit on inflation from B-modes. Dr. Kovac is now principal investigator (PI) of the collaboration that fielded, operates, and analyzes data from BICEP2 and SPUD. The combined BICEP2/SPUD system concentrates its sensitivity on a small foreground-clean region to optimize the search for the CGB. As other CMB polarization surveys come online in the near future, demand will grow for joint analysis of overlapping maps. Given the major implications of a B-mode detection, any claim will need to be confirmed by rigorous map-level comparisons among independent experiments. Separation of polarized Galactic emission and removal of contributions of gravitational lensing to the B-mode signature also require the joint use of surveys. The study of dark energy and neutrinos and other science goals motivate correlation of CMB maps with optical and radio cosmological surveys.
This project seeks to share ultra-deep CMB polarization maps from SPUD, BICEP2, BICEP1, and DASI. It develops and disseminates complete data products and software tools that broaden the use and impact of those pathfinding surveys while setting what are expected to be useful standards for others to do the same. This project aims to derive the needed portable data products and software tools, to test them in key joint analyses of overlapping maps with external collaborators including SPT, to share them with the full astrophysics community, and to encourage independent reanalysis. Such reanalysis by the astrophysics community, strongly motivated by the science goals above, may also yield unanticipated discoveries.
This project integrates education with research by directly broadening the audience for CMB science. The PI will develop and share a portable curriculum based on a highly successful CMB discovery laboratory aimed at undergraduate students, which will be used across many undergraduate teaching institutions. The PI will also publish virtual tours of the early Universe and interactive deep CMB maps, which may directly image primordial gravitational waves, through the WorldWide Telescope, a web-based astronomy visualization tool used for public and secondary-school educational outreach. This project provides training for a graduate student and postdoctoral fellow who will work closely with the PI on these and other elements of the education and research plan.
