Extragalactic science, cosmology, and Galactic archaeology with the Subaru Prime Focus Spectrograph

Abstract

The Subaru Prime Focus Spectrograph (PFS) is a massively-multiplexed fiber-fed optical and near-infrared 3-arm spectrograph (N fiber =2400, 380≤ λ ≤ 1260nm, 1.3 degree diameter hexagonal field), offering unique opportunities in survey astronomy. Following a successful external design review the instrument is now under construction with first light anticipated in late 2017. Here we summarize the science case for this unique instrument in terms of provisional plans for a Subaru Strategic Program of ≃300 nights. We describe plans to constrain the nature of dark energy via a survey of emission line galaxies spanning a comoving volume of 9.3h −3 Gpc 3 in the redshift range 0.8 < z < 2.4. In each of 6 independent redshift bins, the cosmological distances will be measured to 3% precision via the baryonic acoustic oscillation scale, and redshift-space distortion measures will be used to constrain structure growth to 6% precision. In the near-field cosmology program, radial velocities and chemical abundances of stars in the Milky Way and M31 will be used to infer the past assembly histories of spiral galaxies and the structure of their dark matter halos. Data will be secured for 10 6 stars in the Galactic thick-disk, halo and tidal streams as faint as V ∼ 22, including stars with V < 20 to complement the goals of the Gaia mission. A medium-resolution mode with R = 5, 000 to be implemented in the red arm will allow the measurement of multiple α-element abundances and more precise velocities for Galactic stars, elucidating the detailed chemo-dynamical structure and evolution of each of the main stellar components of the Milky Way Galaxy and of its dwarf spheroidal galaxies. The M31 campaign will target red giant branch stars with 21.5< V <22.5, obtaining radial velocities and metallicities over an unprecedented area of 65 deg 2 . For the extragalactic program, our simulations suggest the wide wavelength range of PFS will be particularly powerful in probing the galaxy population and its clustering over a wide redshift range. We propose to conduct a color-selected survey of 1 < z < 2 galaxies and AGN over 16 deg 2 to J ≃23.4, yielding a fair sample of galaxies with stellar masses above ∼ 10 10 M ⊙ at z ≃ 2. A two-tiered survey of higher redshift Lyman break galaxies and Lyman alpha emitters will quantify the properties of early systems close to the reionization epoch. PFS will also provide unique spectroscopic opportunities beyond these currentlyenvisaged surveys, particularly in the era of Euclid, LSST and TMT.

Looking through the same lens: Shear calibration for LSST, Euclid, and WFIRST with stage 4 CMB lensing

“…Understanding the physics of cosmic acceleration is the aim of many ongoing and upcoming imaging surveys such as the Kilo-Degree Survey (KiDS) [1], the Dark Energy Survey (DES) [2,3], the Subaru Hyper Suprime-Cam (HSC) survey [4,5], the Subaru Prime Focus Spectrograph (PFS) [6,7], the Dark Energy Spectroscopic Instrument (DESI) [8], the Large Synoptic Survey Telescope (LSST) [9], the ESA satellite mission Euclid [10], and NASA's Wide-Field Infrared Survey Telescope (WFIRST) [11]. Through gravitational lensing, images of distant sources such as galaxies or the cosmic microwave background (CMB) are distorted by the presence of foreground mass.…”

Nonlinear reconstruction

“…Ambitious surveys are mapping large swaths of the visible Universe (e.g. CHIME [1], Tianlai [2], DESI [3], PFS [4], and SDSS [5], etc). Precision measurements of baryon acoustic oscillations (BAO), redshift space distortions (RSD), and primordial non-Gaussianity, etc are continually improving [6][7][8][9][10].…”

Geometrical constraint on curvature with BAO experiments

“…We employ the method in Ref. [32] to compute the CMB Fisher matrix, where we assumed the standard ΛCDM model for the physics prior to recombination that determines the sound horizon scale or the BAO scale.…”