Collaborative Research: Exploring Early Galaxy Formation and the Epoch of Reionization with the Hawaii-Two-0 (H20) Survey

University Of Hawaii, Honolulu

Investigators

Abstract

Understanding how and when galaxies form necessarily involves the study of incredibly distant and faint objects. Since spectroscopy of many hundreds of millions of extremely faint galaxies is not feasible currently, deep- and high-resolution imaging surveys covering many square degrees are the preferred method for identifying targets for spectroscopic follow-up. Images obtained through multiple filters spanning a wide wavelength range – in effect, a form of very low-resolution spectroscopy - can be used to derive important properties such as approximate redshifts (distances), stellar masses, and star formation activity, in addition to morphology and their environments. This award will support the completion and early analysis of the Hawaii Two-0 (H20) survey, an ultra- deep and multi-wavelength galaxy survey covering two contiguous 10-square degree regions of the sky in eight bands spanning 0.36 to 4.5 microns in wavelength. The survey includes follow-up spectroscopy with Keck and overlaps fields targeted for deep observations by the Euclid Space Telescope. The award also supports graduate student research, enables the participation of undergraduate and local high school students in research activities, develops general educational classes in Spanish, and multiple public outreach events. The H20 imaging data will provide the largest and only cosmologically significant sample for the foreseeable future and is expected to uncover 500,000 high-z Lyman Break galaxies, 12,000 quiescent systems and 50-100 proto-clusters at z= 3-7, with derived photometric redshifts, stellar masses, star formation rates and extinction. These data will provide the first definitive constraint on the evolution of massive high-z galaxies, a study of the mass function for different populations of galaxies as a function of redshift and environment, the identification of proto-clusters, and a search for rare objects believed responsible for re-ionizing the Universe during the initial epoch of galaxy formation. Guaranteed Keck spectroscopy will be used to find redshifts and calibrate photometric redshifts, confirm proto-clusters, measure the strength of the Ly-alpha lines to search for high- escape fraction objects and to measure spectral line diagnostics of galaxy physical parameters. Innovative data science techniques (e.g., self-organizing maps; SOMs) will be developed and applied to the multi-dimensional H20 data to extract maximum scientific information. The H20 catalogs will additionally be essential for building the Euclid calibration fields. 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.