Cosmology with the SPHEREX All-Sky Spectral Survey

Abstract

SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer) [Website] is a proposed all-sky spectroscopic survey satellite designed to address all three science goals in NASA's Astrophysics Division: probe the origin and destiny of our Universe; explore whether planets around other stars could harbor life; and explore the origin and evolution of galaxies. SPHEREx will scan a series of Linear Variable Filters systematically across the entire sky. The SPHEREx data set will contain R=40 spectra fir 0.75< λ <4.1µm and R=150 spectra for 4.1< λ <4.8µm for every 6.2 arcsecond pixel over the entire-sky. In this paper, we detail the extra-galactic and cosmological studies SPHEREx will enable and present detailed systematic effect evaluations. We also outline the Ice and Galaxy Evolution Investigations. I. SPHEREX MISSION OVERVIEWSPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer; PI: J. Bock) is a proposed all-sky survey satellite designed to address all three science goals in NASA's Astrophysics Division: probe the origin and destiny of our Universe; explore whether planets around other stars could harbor life; and explore the origin and evolution of galaxies. All of these exciting science themes are addressed by a single survey, with a single instrument, providing the first near-infrared spectroscopy of the complete sky. In this paper, we will focus on the cosmological science enabled by SPHEREx and outline the Galactic Ices and the Epoch of Reionization (EOR) scientific investigations.SPHEREx will probe the origin of the Universe by constraining the physics of inflation, the superluminal expansion of the Universe that took place some 10 −32 s after the Big Bang. SPHEREx will study its imprints in the threedimensional large-scale distribution of matter by measuring galaxy redshifts over a large cosmological volume at low redshifts, complementing high-redshift surveys optimized to constrain dark energy.SPHEREx will investigate the origin of water and biogenic molecules in all phases of planetary system formation -from molecular clouds to young stellar systems with protoplanetary disks -by measuring absorption spectra to determine the abundance and composition of ices toward > 2 × 10 4 Galactic targets. Interstellar ices are the likely source for water and organic molecules, the chemical basis of life on Earth, and knowledge of their abundance is key to understanding the formation of young planetary systems as well as the prospects for life on other planets.SPHEREx will chart the origin and history of galaxy formation through a deep survey mapping large-scale structure. This technique measures the total light produced by all galaxy populations, complementing studies based on deep galaxy counts, to trace the history of galactic light production from the present day to the first galaxies that ended the cosmic dark ages.SPHEREx will be the first all-sky near-infrared spectral survey, creating a legacy archive of spectra (0.75 ≤ λ ≤...

Deep Radio Interferometric Imaging with POLISH: DSA-2000 and weak lensing

“…Approximately 30 million galaxies at z < 1 will have spectroscopic redshifts from the DSA's HI survey. The SPHEREx near-infrared all-sky survey (Doré et al 2014) will determine the redshifts of over one billion galaxies with σ z /(1+z) ≤ 10% and a subset of several hundred million galaxies with σ z /(1+z) ≤ 1% (see here 8 for current forecasts). Of these, three quarters can be cross-matched with the DSA-2000 catalog.…”

Precision Tests of CO and [CII] Power Spectra Models against Simulated Intensity Maps

“…The large-scale structure (LSS) contains invaluable information about the origin, composition, and evolution of the Universe and provides an incredible opportunity for precision tests of fundamental physics. In addition to ever-increasing precision and volume of upcoming galaxy surveys, such as DESI [1], EUCLID [2], SPHEREx [3], and LSST [4], line intensity mapping is emerging as a powerful technique to map a significant fraction of the sky and over extended redshift epochs, largely inaccessible to other LSS probes [5][6][7]. In contrast to galaxy surveys, which trace the LSS by resolving individual sources, LIM measures the integrated emission from spectral lines, originating from diffuse IGM and unresolved galaxies (including the faintest ones).…”

“…Tentative recent detections of CO intensity shot power spectrum by COPSS [27][28][29] and mmIME [30] surveys, and [CII] emission via cross-correlation between Planck and SDSS quasars [12] have further amplified the growing observational and theoretical interest in LIM. Looking ahead, in addition to several 21-cm surveys, a wide range of ground-and space-based experiments (e.g., COMAP [10], TIME [31], CONCERTO [32], CCAT-prime [33] EXCLAIM [34], SPHEREx [3] and CDIM [35]) will provide higher-fidelity detection of line intensity fluctuations at different redshifts from several emission lines 1 . Success of these surveys will pave the way for next generation wide-field LIM surveys (e.g., [36,37]), capable of providing precision cosmological constraints.…”

“…Assuming the commonly used empirical semi-analytic relations between the line luminosities and halo mass (see. e.g., [10]) 3 , in this paper, we study two aspects of the modeling of line power spectrum signal; the impact of nonlinearities in the matter fluctuations and in the line-matter biasing relation, and the deviations from the commonly assumed Poisson shot noise. The former aspect is relevant since although the matter fluctuations are more linear at high redshifts, the nonlinear biasing becomes more critical as the value of the halo/line bias increases with redshifts [50].…”

The THESAN project: predictions for multi-tracer line intensity mapping in the Epoch of Reionization

“…The Origins Space Telescope (Wiedner et al 2020) will observe a host of far-IR lines emanating from high-𝑧 galaxies including [O ] (63 𝜇m), [O ] (52 and 88 𝜇m), [N ] (122 𝜇m) and [C ] (158 𝜇m), to name just a few. The Spectro-Photometer for the history of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx; Doré et al 2014) is scheduled to be launched in 2024 and is designed to measure a host of rest frame optical/UV emission lines including H 𝛼, H 𝛽, Ly 𝛼, [O ] (3726, 3729 Å) and [O ] (4959, 5007 Å) over a wide redshift range (𝑧 = 0-12). Finally, the proposed Cosmic Dawn Intensity Mapper (CDIM; Cooray et al 2019) aims to map H 𝛼, Ly 𝛼 and [O ] (4959, 5007 Å) at 𝑧 = 0.2-10, with a much higher sensitivity.…”