[论文解读] The Prime Focus Spectrograph Galaxy Evolution Survey

Jenny E. Greene, Rachel Bezanson+3 more|arXiv (Cornell University)|Jun 29, 2022

Astronomy and Astrophysical Research被引用 22

一句话总结

本论文概述了 Subarū PFS 的 Prime Focus Spectrograph Galaxy Evolution (GE) 调查的设计与科学目标，详细说明了样本、策略，以及在从 z~7 到 z~0.7–6 的星系演化、宇宙网绘制和 IGM 层析方面的潜在贡献。

ABSTRACT

We present the Prime Focus Spectrograph (PFS) Galaxy Evolution pillar of the 360-night PFS Subaru Strategic Program. This 130-night program will capitalize on the wide wavelength coverage and massive multiplexing capabilities of PFS to study the evolution of typical galaxies from cosmic dawn to the present. From Lyman alpha emitters at z~7 to probe reionization, drop-outs at z~3 to map the inter-galactic medium in absorption, and a continuum-selected sample at z~1.5, we will chart the physics of galaxy evolution within the evolving cosmic web. This article is dedicated to the memory of Olivier Le Fevre, who was an early advocate for the construction of PFS, and a key early member of the Galaxy Evolution Working Group.

研究动机与目标

• Motivate a large, dense spectroscopic survey to study galaxy evolution across cosmic time (z ~ 0.7–7) and its connection to the cosmic web.
• Design a multi-sample GE program leveraging PFS capabilities (wide wavelength range, high multiplexing) to probe ISM/CGM, star formation histories, and environmental effects.
• Harness deep imaging from HSC-SSP and synergy with future facilities to map large-scale structure and IGM at multiple epochs (reionization to cosmic noon).
• Quantify how galaxy properties (mass, SFR, metallicity) relate to halo assembly and environment, testing galaxy–halo connection models including assembly bias.

提出的方法

• Describe the instrument and survey design of PFS (2394 fibers, 1.25 deg^2 field, 0.38–1.25 μm coverage).
• Define and optimize target samples (Continuum, IGM tomography, LBG, LAE, AGN-GE) with specified redshift ranges and selection criteria.
• Use deep imaging (HSC-SSP) for target selection and complement with Lyα tomography and 21 cm cross-correlation in conjunction with SKA for reionization studies.
• Provide exposure time allocations (2–12 hr per target type) to achieve redshift completeness and enable stellar population, abundance, and CGM studies.
• Leverage mock catalogs and sensitivity assumptions to forecast deliverables and clustering signals for the SMHM relation and assembly bias tests.

实验结果

研究问题

• RQ1 How does the distribution of galaxies and gas trace the evolving cosmic web from z~7 to z~0.7–1.7?
• RQ2 What is the shape and evolution of the stellar mass–halo mass (SMHM) relation and the role of assembly bias at z>1?
• RQ3 How do gas inflows and outflows (CGM/IGM) evolve over cosmic time and relate to star formation histories and AGN activity?
• RQ4 Can cross-correlations between LAEs and 21 cm emission constrain the topology and history of reionization?
• RQ5 What environmental dependencies affect star formation, quenching, and metallicity evolution across cosmic time?

主要发现

Type	Redshift range	Selection	Exp. Time	# of spectra
Continuum	0.7-2	y,J<22.8	2, 12	261, 14
IGM	2.1-3.5	y<24.3 , g<24.7	6, 12	30.3, 14
LBG	3.5-7	y<24.5	6	22
LAE	2.2, 5.7, 6.6	Lyα>3×10^42 erg s^-1	3, 6, 12	7.4, 4.5, 2.8
AGN-GE	0.5-6.0	various (see text)	1-5	4.2

• The GE survey design enables half a million galaxy spectra over z~0.7–6, with unprecedented sampling density and spectral coverage to study galaxy evolution and its environment.
• It enables high-fidelity maps of the cosmic web, IGM tomography at z~2.1–2.5, and LAE-based reionization probes at z~6–7, offering multi-epoch environmental tests.
• The plan foresees robust constraints on the SMHM relation and assembly bias through dense 3D clustering measurements extending to z~4.5.
• The survey anticipates deep spectroscopy (up to 12 hours) to recover detailed star formation histories, abundance ratios, and CGM/IGM properties in hundreds of thousands of galaxies.
• PFS-GE is positioned to complement Euclid/Roman grism surveys and MOONS, with unique capabilities in blue coverage and high multiplexing enabling IGM and CGM studies.