Cosmic acceleration is the most surprising cosmological discovery in many
decades. Testing and distinguishing among possible explanations requires
cosmological measurements of extremely high precision probing the full history
of cosmic expansion and structure growth and, ideally, compare and contrast
matter and relativistic tracers of the gravity potential. This program is one
of the defining objectives of the Wide-Field Infrared Survey Telescope
(WFIRST), as set forth in the New Worlds, New Horizons report (NWNH) in 2010.
The WFIRST mission has the ability to improve these measurements by 1-2 orders
of magnitude compared to the current state of the art, while simultaneously
extending their redshift grasp, greatly improving control of systematic
effects, and taking a unified approach to multiple probes that provide
complementary physical information and cross-checks of cosmological results. We
describe in this annual report the activities of the Science Investigation Team
(SIT) "Cosmology with the High Latitude Survey (HLS)" during the year 2017.
This team was selected by NASA in December 2015 in order to address the
stringent challenges of the WFIRST dark energy (DE) program through the
Project's formulation phase. This SIT has elected to jointly address Galaxy
Redshift Survey, Weak Lensing and Cluster Growth and thus fully embrace the
fact that the imaging and spectroscopic elements of the HLS will be realized as
an integrated observing program, and they jointly impose requirements on
performance and operations. WFIRST is designed to be able to deliver a
definitive result on the origin of cosmic acceleration. It is not optimized for
Figure of Merit sensitivity but for control of systematic uncertainties and for
having multiple techniques each with multiple cross-checks. Our SIT work
focuses on understanding the potential systematics in the WFIRST DE
measurements.

WFIRST 是一个广域红外巡天望远镜，其可观测到精度极高的宇宙扩张和结构增长，同时用于探测物质和相对论引力场下的追踪者，旨在解释和区分可能的宇宙加速度的解释方式。本论文着重于研究项目中所包含的系统误差，并强调联合观测的重要性，以实现控制误差和获得物理信息的目标。

WFIRST 高纬度测量与宇宙学年度报告 2017

WFIRST Science Investigation Team "Cosmology with the High Latitude  Survey" Annual Report 2017

We present a power spectrum analysis of the final 2dF Galaxy Redshift Survey,
employing a direct Fourier method. The sample used comprises 221,414 galaxies
with measured redshifts. We investigate in detail the modelling of the sample
selection. A new angular mask is derived, based on revisions to the photometric
calibration. The redshift selection function is determined by dividing the
survey according to rest-frame colour, and deducing a self-consistent treatment
of k-corrections and evolution for each population. The covariance matrix for
the power-spectrum estimates is determined using two different approaches to
the construction of mock surveys which are used to demonstrate that the input
cosmological model can be correctly recovered. We are confident that the 2dFGRS
power spectrum can be used to infer the matter content of the universe. On
large scales, our estimated power spectrum shows evidence for the `baryon
oscillations' that are predicted in CDM models. Fitting to a CDM model,
assuming a primordial $n_{s}=1$ spectrum, $h=0.72$ and negligible neutrino
mass, the preferred parameters are $\Omega_{M} h = 0.168 \pm 0.016$ and a
baryon fraction $\Omega_{b} /\Omega_{M} = 0.185\pm0.046$ (1$\sigma$ errors).
The value of $\Omega_{M} h$ is $1\sigma$ lower than the $0.20 \pm 0.03$ in our
2001 analysis of the partially complete 2dFGRS. This shift is largely due to
the signal from the newly-sampled regions of space, rather than the refinements
in the treatment of observational selection. This analysis therefore implies a
density significantly below the standard $\Omega_{M} =0.3$: in combination with
CMB data from WMAP, we infer $\Omega_{M} =0.231\pm 0.021$. (Abridged.)

本文介绍了对 2dF 星系红移差异调查的功率谱分析，探讨了样本选择的建模，分析了数据集中的红移选择函数，并构建了虚拟调查，从而证明了输入的宇宙模型可以得到正确的恢复。研究表明，2dFGRS 功率谱可以用来推断宇宙的物质含量，而且在大尺度上，我们估计的功率谱显示出在 CDM 模型中预测的 “重子振荡”。