Science Impacts of the SPHEREx All-Sky Optical to Near-Infrared Spectral Survey II: Report of a Community Workshop on the Scientific Synergies Between the SPHEREx Survey and Other Astronomy Observatories

Abstract

SPHEREx, the Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer, is a proposed NASA MIDEX mission selected for Phase A study pointing to a downselect in early CY2019, leading to launch in CY2023. SPHEREx would carry out the first all-sky spectral survey at wavelengths between 0.75 and 2.42 µm [with spectral resolution R=41], 2.42 and 3.82 µm [with R=35], 3.82 and 4.42 µm [with R=110], and 4.42 and 5.00 µm [with R=130]. At the end of its two-year mission, SPHEREx would obtain 0.75-to-5µm spectra of every 6.2×6.2 arcsec pixel on the sky, with a 5-sigma sensitivity AB>19 per spectral/spatial resolution element. SPHEREx would obtain spectra of every sources in the 2MASS PSC (1.2µm, 1.6µm, 2.2µm) catalog to at least (40 σ, 60 σ, 150 σ) per spectral channel, and spectra with S/N ≥3 per frequency element of the faintest sources detected by WISE. More details concerning SPHEREx are available at http://spherex.caltech.edu. The SPHEREx team has proposed three specific science investigations to be carried out with this unique data set: cosmic inflation, interstellar and circumstellar ices, and the extra-galactic background light.Though these three scientific issues are undoubtedly compelling, they are far from exhausting the scientific output of SPHEREx. Indeed, as Table 1 shows, SPHEREx would create a unique all-sky spectral database including spectra of very large numbers of astronomical and solar system targets, including both extended and diffuse sources. These spectra would enable a wide variety of scientific investigations, and the SPHEREx team is dedicated to making the SPHEREx data available to the scientific community to facilitate these investigations, which we refer to as Legacy Science. To that end, we have sponsored two workshops for the general scientific community to identify the most interesting Legacy Science themes and to ensure that the SPHEREx data products are responsive to their needs. In February of 2016, some 50 scientists from all scientific fields met in Pasadena to develop these themes and to understand their implications for the SPHEREx mission. The results of this initial workshop are reported in Doré et al., 2016. Among other things, discussions at the 2016 workshop highlighted many synergies between SPHEREx Legacy Science and other contemporaneous astronomical missions, facilities, and databases. Consequently, in January 2018 we convened a second workshop at the Center for Astrophysics in Cambridge to focus specifically on these synergies. This white paper, which contains substantial contributions from the participants, presents some of the highlights of the 2018 SPHEREx workshop. 1

Escape from the swamp with spectator

“…9 Here Γ σ = ∂Γ/∂σ and Γ σσ = ∂ 2 Γ/∂σ 2 . Such an order unity non-Gaussianity can be compatible with the current constraint f NL = −0.9 ± 5.1 [71], and moreover can be detectable with future galaxy surveys as SPHEREx [74,75], LSST [76], and Euclid [77] and/or 21cm observations like SKA [78] for example. We leave further discussions about the conversion mechanism and the resultant non-Gaussianity for future works.…”

Grid-based calculations of redshift-space matter fluctuations from perturbation theory: UV sensitivity and convergence at the field level

“…Applying the multipole expansion to each term, the multipole moments of the redshift-space power spectrum and bispectrum are respectively evaluated up to = 4 and = 2, together with the real-space power spectrum and bispectrum 7 .…”

“…They also offer a clue to probe the primordial fluctuations, from which one can address the fundamental physics questions of the early universe. In addition to several ongoing ground-based surveys such as HETDEX [2], PFS [3] and DESI [4], there are spacebased missions planned to probe galaxies out to higher redshifts over a large sky area, such as Euclid 1 [5], Nancy Grace Roman Space Telescope 2 [6], and SPHEREx 3 [7]. Those gigantic surveys aim to dramatically improve our understanding of the universe to the next level, and to resolve puzzles such as the nature of dark matter and dark energy, and the physics of cosmic inflation.…”

Evolution of Dust and Water Ice in Cometary Comae by Radiative Torques

“…Understanding the desorption mechanism (when and where) of water ice from comets is crucial for accurate determination of the nuclei radius and the volume based on the measurement of water vapor. Future space telescopes with SPHEREx (Doré et al 2018), LSST, and JWST (United States Congress House Committee on Science & 2011 2018) would provide unprecedented data of water ice and vapor, and an accurate determination of ice requires an accurate understanding of their phase transition. The current model of ice vaporization is based on thermal sublimation from icy grains (Cowan & A'Hearn 1979).…”