Session L10: Mini-Symposium: Advances in Spectroscopic Cosmology

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The extended baryon oscillation spectroscopic survey (eBOSS) concluded observations of baryon acoustic oscillations (bao) and redshift-space distortions (RSD) in February, 2019. When combined with the prior samples of galaxy and lyman-alpha forest spectroscopic data within the Sloan Digital Sky Survey, eBOSS allows an exploration of the cosmic distance scale and the growth of structure out to a redshift of z$=\sout{3.5}$. I will present an overview of the eBOSS experiment and the final BAO and RSD measurements. I will then demonstrate the advances by the stage-III BOSS and eBOSS dark energy experiments for modeling dark energy, gravity, and massive neutrino.   

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The Dark Energy Spectroscopic Instrument (DESI) is a powerful, new experiment funded by the U.S. Department of Energy to understand the nature of dark energy. DESI will measure spectra of 35 million galaxies and quasars over 14000 square degrees. The DESI instrumentation includes a new prime focus corrector for the KPNO Mayall telescope, 5000 fiber optic positioners, ten, broad-band spectrographs, and sophisticated software systems to both control the instrumentation and quickly distribute processed data products to the collaboration. I will present the status of the DESI instrumentation and the plan for the 5-year survey.   

Live

The Dark Energy Spectroscopic Instrument (DESI) will soon begin a redshift survey of more than 30 million galaxies and quasars to constrain the Universe's expansion history over most of cosmic time. The DESI collaboration is using a combination of optical and infrared imaging to select targets for spectroscopic follow-up. In the optical, DESI targeting relies on $g$, $r$ and $z$-band images from the Dark Energy Camera Legacy Survey, the Mayall $z$-band Legacy Survey and the Beijing-Arizona Sky Survey, which are collectively known as the DESI Legacy Surveys (www.legacysurvey.org). These imaging data sets are combined with infrared imaging from the Wide-field Infrared Survey Explorer (WISE) satellite to produce an extremely rich inference-based catalog of sources in the sky. I will present an overview of Data Release 9 (DR9) of the Legacy Surveys, the final Data Release that will be considered for use in DESI target selection. Beyond DESI targeting, the Legacy Surveys have been, and will continue to be, a rich resource for scientific discovery in their own right.   

Live

Baryon Acoustic Oscillations are a primordial sound-wave feature imprinted in the large scale clustering of matter and galaxies. Many previous, current (e.g., eBOSS), and upcoming galaxy surveys (e.g., DESI) are dedicated to using this feature as a standard ruler to robustly probe the expansion history of the Universe. In this talk, I plan to present how BAO is used as the standard ruler and why BAO is a robust dark energy probe.   

Live

The Lyman-alpha forest, which can be measured in the spectra of high-redshift quasars, is a rich source of information. Because it gives access to scales as small as a few tens of Mpc, it allows one to probe the impact, on matter clustering, of the free-streaming of massive neutrinos and warm dark matter particles. The Extended Baryon Oscillation Spectroscopic Survey (eBOSS) measured the Lyman-alpha absorption along nearly 200.000 lines of sight. I will present the constraints on neutrino mass that were derived from these data, which stand among the most stringent limits to date. I will show how the Lyman-alpha data can also lead to competitive constraints on warm dark matter. Finally, I will present the improvements we expect on these topics from the upcoming Dark Energy Spectroscopic Instrument (DESI).   

Live

Spectroscopy from the Dark Energy Spectroscopic Instrument will allow us to construct a 3D map of the distribution of matter in the Universe over an area of 14,000 deg$^2$ and out to a redshift $z<4$. This will allow precise measurements of the rate at which structure forms in the Universe and therefore, provide a test on our theory of gravity. On large scales, these measurements are enabled by redshift space distortions. I will review both the state of the theory and observations at the start of DESI, the forecasted improvements that DESI will provide, and the challenges to achieving these measurements. I will also discuss opportunities to test gravity on smaller scales and how these might provide complementary information to the large scale tests.   

Live

The DESI (Dark Energy Spectroscopic Instrument) will obtain spectroscopic redshifts for tens of millions of galaxies and quasars over 14,000 deg2. The DESI footprint will also overlap with a number of other large area data-sets (imaging, CMB, 21cm, X-rays, etc). I will present the new scientific opportunities that will be afforded by the overlap between DESI and these other data sets. Cross-correlations between DESI and lensing surveys (HSC, KiDS, DES) will provide a powerful test of General Relativity. The overlap between DESI, CMB, and X-ray data provides opportunities to better understand the properties of the gaseous component of dark matter halos as well as to measure the growth history via the dark matter mass function. Cross-correlations between DESI and 21cm surveys may yield new and orthogonal constraints on the expansion history via BAO.   

Live

The Dark Energy Spectroscopic Instrument (DESI) begins the next chapter of cosmology using spectroscopic redshift surveys. I will describe the opportunities and challenges for future redshift surveys of the distant universe. The key technical challenges can be addressed with novel optical designs, increased multiplexing of robotic fiber systems, and the recovery of galaxy redshifts in the lowest-possible signal regime.