Cosmology with the galaxy clustering measurement of the HETDEX survey

Cosmology leaps to a new level each time we expand the distances-measurement horizon. The existence of the extragalactic Universe and its expansion was revealed only after reaching out to a few Mega light-years; subsequent extension of the horizon to a few Giga light-years led to the discovery of the Universe’s accelerating expansion. Cosmic acceleration indicates that new physics must operate on even greater cosmological scales, and astronomers coined the term Dark Energy to address this problem. Scientists at Penn State University propose to address the Dark Energy problem using the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) galaxy survey data, which observed 1.5 Million galaxies within a cosmological volume (400 cubic Giga light-years) at tens of Giga light-years away. By scrutinizing the clustering of these ancient galaxies, the team will measure the Dark Energy density at the earliest time test whether Dark Energy varies in time. With the same dataset, the team will also study the physics of the early Universe that generated the initial seeds for the observed large-scale structure. As part of this project, the team will educate new Ph.D. students and create undergraduate research opportunities. The team will also engage in outreach activities at Penn State University by presenting public lectures during AstroFest and AstroNight and by organizing the Neighborhood Workshop on Astrophysics and Cosmology. The team will measure the Dark Energy density at high redshift (1.9This 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.