|Speaker:||Gary Hill (U. Texas)|
|Title:||HETDEX: the Hobby-Eberly Telescope, VIRUS, and the evolution of dark energy|
|Date (JST):||Thu, Dec 08, 2016, 13:30 - 14:30|
|Place:||Seminar Room A|
The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) is outfitting the 10 m HET with a new wide field and an array of 156 integral-field spectrographs to survey a 420 sq. degree area in the north galactic cap, plus a smaller equatorial field. Each fiber-coupled unit spectrograph covers 350-550 nm, simultaneously at 6 A resolution, providing in total ~35,000 spectra per exposure. This instrument, called VIRUS, will open up large volume surveys of the emission-line universe for the first time, and in particular will be used to detect ~0.8 million Lyman-alpha emitting (LAE) galaxies with 1.9 < z < 3.5 and more than a million [OII] emitting galaxies with z < 0.5.
The upgraded HET is starting science operations and we have deployed 20% of VIRUS. The HETDEX survey will start in second half of 2017. The resulting 3-D map of LAE galaxies in 9 cubic Gpc volume will be used to constrain the expansion history at this early epoch to percent accuracy, and will provide an unprecedented sample with which to probe the properties of LAEs at the epoch where star formation activity in the Universe peaks. In addition to providing the tightest constraint on the possible evolution of dark energy, the dataset will constrain the curvature of the universe more tightly than Planck. I will discuss the status of the experiment and highlight the unique aspects of HETDEX.