Recent calculations using non-linear relativistic cosmological perturbation theory show biases in the mean luminosity distance and distance modulus at low redshift. We show that these effects may be understood very simply as a non-relativistic, and purely kinematic, Malmquist-like bias, and we describe how the effect changes if one averages over sources that are limited by apparent magnitude. This effect is essentially identical to the distance bias from small-scale random velocities that has previously been considered by astronomers, though we find that the standard formula overestimates the homogeneous bias by a factor 2.
We prove from the modified gravity (MG) galaxy/halo mock catalogs that the shape of the pairwise kinematic Sunyaev-Zeldovich (kSZ) power spectrum $P_{\rm kSZ}$ has constraining power on discriminating different gravity theories on cosmological scales. By varying the effective optical depth $τ_{\rm T}$ as a free parameter, we verify that the $τ_{\rm T}$-$f$ (the linear growth rate) degeneracy in the linear theory of $P_{\rm kSZ}$ is broken down by the non-linear structure growth and the scale-dependence of $f$ in some MG theories. Equivalently speaking, the shape of $P_{\rm kSZ}$ alone could be…
The power spectrum of reconstructed cosmic microwave background (CMB) lensing maps is a powerful tool for constraints on cosmological parameters like the sum of the neutrino masses and the dark energy equation of state. One possible complication is the kinematic Sunyaev-Zel'dovich (kSZ) effect, due to the scattering of CMB photons by moving electrons, which can bias the reconstruction of the CMB lensing power spectrum through both kSZ-lensing correlations and the non-Gaussianity of the kSZ temperature anisotropies. We investigate for the first time the bias to CMB lensing reconstruction from t…
The kinematics of the Milky Way (MW) and M31, the dominant galaxies in the Local Group (LG), can be used to estimate the LG total mass. New results on the M31 proper motion have recently been used to improve that estimate. Those results are based on kinematic priors that are sometimes guided and evaluated using cosmological N-body simulations. However, the kinematic properties of simulated LG analogues could be biased due to the effective power spectrum truncation induced by the small size of the parent simulation. Here we explore the dependence of LG kinematics on the simulation box size to a…
Non-parametric estimation of the baryon gas fraction and the cosmological bias with clusters
Sejong University（世宗大学）；Sapienza Università di Roma（罗马第一大学）；Université Paris-Saclay, CNRS, Institut d’Astrophysique Spatiale（巴黎萨克雷大学、法国国家科学研究中心、空间天体物理研究所）；Korea Astronomy and Space Science Institute（韩国天文与空间科学研究院）；University of Science and Technology（科学技术大学）
The cosmological principle states that our Universe is statistically homogeneous and isotropic at large scales. However, due to the relative motion of the Solar System, an additional kinematic dipole can be detected in the distribution of galaxies, which should be consistent with the dipole observed in the cosmic microwave background temperature. In this paper, we forecast the mock number count maps from the China Space Station Telescope photometric survey to reconstruct the kinematic dipole. Using the whole photometric mock data, we obtain a positive evidence for the dipole signal detection a…
Cosmological Applications of the Gaussian Kinematic Formula
高斯运动学公式（GKF，参见Adler and Taylor（2007，2011））是一个非常强大的工具，允许在现实的宇宙学数据收集实验条件下对Minkowski泛函的期望值进行显式的分析预测。在本文中，我们实现了Minkowski泛函的多极子和针组件的CMB字段，从而允许更好地控制宇宙方差和提取信息的谐波和实域;然后，我们利用GKF提供他们的期望值的球面地图上，在存在任意的天空面具，在非高斯的情况下。所有的结果都通过数值实验进行了验证，实验结果表明理论预测与蒙特卡罗模拟结果吻合良好。
The magnification of galaxies in modern galaxy surveys induces additional correlations in the cosmic shear, galaxy-galaxy lensing and clustering observables used in modern lensing "3x2pt" analyses, due to sample selection. In this paper, we emulate the magnification contribution to all three observables utilising the SLICS simulations suite, and test the sensitivity of the cosmological model, galaxy bias and redshift distribution calibration to un-modelled magnification in a Stage-IV-like survey using Monte-Carlo sampling. We find that magnification cannot be ignored in any single or combined …
We determine the error introduced in a joint halo model analysis of galaxy-galaxy lensing and galaxy clustering observables when adopting the standard approximation of linear halo bias. Considering the Kilo-Degree Survey, we forecast that ignoring the non-linear halo bias would result in up to 5$σ$ offsets in the recovered cosmological parameters describing structure growth, $S_8$, and the matter density parameter, $Ω_{\mathrm{m}}$. We include the scales $10^{-1.3}<r_{\rm{p}} \ / h^{-1}\, \mathrm{Mpc}<10$ in the data vector, and the direction of these offsets are shown to depend on the freedom…
The study of the magnification bias produced on high-redshift sub-millimetre galaxies by foreground galaxies through the analysis of the cross-correlation function was recently demonstrated as an interesting independent alternative to the weak-lensing shear as a cosmological probe. In the case of the proposed observable, most of the cosmological constraints mainly depend on the largest angular separation measurements. Therefore, we aim to study and correct the main large-scale biases that affect foreground and background galaxy samples to produce a robust estimation of the cross-correlation fu…
We assess the performance of a perturbation theory inspired method for inferring cosmological parameters from the joint measurements of galaxy-galaxy weak lensing ($ΔΣ$) and the projected galaxy clustering ($w_{\rm p}$). To do this, we use a wide variety of mock galaxy catalogs constructed based on a large set of $N$-body simulations that mimic the Subaru HSC-Y1 and SDSS galaxies, and apply the method to the mock signals to address whether to recover the underlying true cosmological parameters in the mocks. We find that, as long as the appropriate scale cuts, $12$ and $8~h^{-1}{\rm Mpc}$ for $…
We present a mitigation strategy to reduce the impact of non-linear galaxy bias on the joint `$3 \times 2 $pt' cosmological analysis of weak lensing and galaxy surveys. The $Ψ$-statistics that we adopt are based on Complete Orthogonal Sets of E/B Integrals (COSEBIs). As such they are designed to minimise the contributions to the observable from the smallest physical scales where models are highly uncertain. We demonstrate that $Ψ$-statistics carry the same constraining power as the standard two-point galaxy clustering and galaxy-galaxy lensing statistics, but are significantly less sensitive t…
We consider the bias introduced by a spatially-varying multiplicative shear bias (m-bias) on tomographic cosmic shear angular power spectra. To compute the bias in the power spectra, we estimate the mode-coupling matrix associated with an m-bias map using a computationally-efficient pseudo-Cl method. This allows us to consider the effect of the m-bias to high l. We then conduct a Fisher matrix analysis to forecast resulting biases in cosmological parameters. For a Euclid-like survey with a spatially-varying m-bias, with zero mean and rms of 0.01, we find that parameter biases reach a maximum o…
Inverting Fisher biases for fast systematics exploration
Leiden University（莱顿大学）；Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology（高等能源物理研究所（IFAE），巴塞罗那科学技术研究院）；Utrecht University（乌得勒支大学）
Cosmic variance or galaxy bias? Disentangling finite-volume and galaxy formation effects in cosmological analysis
Institute for Fundamental Physics of the Universe (IFPU)（宇宙基本物理研究所）；SISSA - International School for Advanced Studies（国际高等研究院）；INAF - Osservatorio Astronomico di Trieste（的里雅斯特天文台）；INFN – National Institute for Nuclear Physics（意大利国家核物理研究所）；Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna（拉古纳大学）
The gas mass fraction in galaxy clusters is a convenient tool to use in the context of cosmological studies. Indeed this quantity allows to constrain the universal baryon fraction $Ω_b/Ω_m$, as well as other parameters like the matter density $Ω_m$, the Hubble parameter $h$ or the Equation of State of Dark Energy $w$. This gas mass fraction is also sensitive to baryonic effects that need to be taken into account, and that translate into nuisance parameters. Two of them are the depletion factor $Υ$, and the hydrostatic mass bias $B = (1 - b)$. The first one describes how baryons are depleted in…
Robustness of pairwise kinematic Sunyaev-Zel'dovich effect to optical-cluster-selection bias
Ludwig-Maximilians-Universität（路德维希-马克西米利安大学）；Max-Planck-Institut für extraterrestrische Physik (MPE)（马克斯·普朗克地外物理研究所）；Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA)（中央研究院天文及天文物理研究所）；Excellence Cluster ORIGINS（ORIGINS卓越集群）；University of Pennsylvania（宾夕法尼亚大学）；Max-Planck-Institut für Astrophysik（马克斯·普朗克天体物理研究所）；University of Chicago（芝加哥大学）；Southern Methodist University（南方卫理公会大学）；European Southern Observatory（欧洲南方天文台）；University of Arizona（亚利桑那大学）
Nonlinear stochastic biasing of halos: Analysis of cosmological N-body simulations and perturbation theories
理解和模拟星系偏置行为对于未来雄心勃勃的星系红移调查至关重要。使用40个大的宇宙学N体模拟的标准的LambdaCDM宇宙学，我们研究的交叉相关系数的物质和晕密度场，这是一个指标的随机性的偏见，在很宽的红移范围0 \le z \le 3。互相关系数对于提取关于物质密度场的信息是重要的，例如，通过结合星系团和星系-星系透镜测量。我们比较了模拟结果与集成微扰理论（iPT）提出的本作者和标准微扰理论（SPT）结合局部偏置的唯象模型。对于我们考虑的所有红移和晕质量，由iPT得到的互相关系数与N体模拟结果在0.5%（1.0%）以内一致，直到r~15（10）h^{-1}Mpc。具有局域偏置的SPT不能解释低红移下准线性尺度上的复杂行为，但大致再现了完全非线性尺度上互相关系数的一般行为。iPT是强大的预测互相关系数下降到准线性制度，具有高精度。
We derive a new relation between cosological distances, valid in any (statistically) isotropic space-time and independent of cosmological parameters or even the validity of the field equation of General Relativity. In particular, this relation yields an equation between those distance ratios which are the geometrical factors determining the strength of the gravitational lensing effect of mass concentrations. Considering a combination of weak lensing shear ratios, based on lenses at two different redshifts, and sources at three different redshifts, we derive a relation between shear-ratio tests…
The Atacama Cosmology Telescope: A Test of the Gravitational Force Law on Cosmological Scales Using the Kinematic Sunyaev-Zeldovich Effect
University of Pennsylvania（宾夕法尼亚大学）；Kavli Institute for Cosmological Physics, University of Chicago（芝加哥大学卡弗里宇宙物理研究所）；University of Southern California（南加州大学）；Columbia University（哥伦比亚大学）；Stanford University（斯坦福大学）；Simons Society of Fellows, Simons Foundation（西蒙斯基金会西蒙斯学者协会）；Cornell University（康奈尔大学）；Sapienza University of Rome（罗马第一大学）；Cardiff University（卡迪夫大学）；University of California, Riverside（加州大学河滨分校）；Pontificia Universidad Católica de Chile（智利天主教 Pontificia 大学）；Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile（智利天主教 Pontificia 大学物理学院天体物理研究所）；Centro de Astro-Ingeniería, Pontificia Universidad Católica de Chile（智利天主教 Pontificia 大学天文工程中心）
Cosmic voids are large underdense regions that, together with galaxy clusters, filaments and walls, build up the large-scale structure of the Universe. The void size function provides a powerful probe to test the cosmological framework. However, to fully exploit this statistics, the void sample has to be properly cleaned from spurious objects. Furthermore, the bias of the mass tracers used to detect these regions has to be taken into account in the size function model. In our work we test a cleaning algorithm and a new void size function model on a set of simulated dark matter halo catalogues,…
The high-z submillimeter galaxies (SMGs) can be used as background sample for gravitational lensing studies thanks to their magnification bias, which can manifest itself through a non-negligible measurement of the cross-correlation function between a background and a foreground source sample with non-overlapping redshift distributions. In particular, the choice of SMGs as background sample enhances the cross-correlation signal so as to provide an alternative and independent observable for cosmological studies regarding the probing of mass distribution. In particular the magnification bias can …
We consider a generic Metric-Affine Cosmological setup and classify some particularly interesting specific cases of Perfect Hyperfluids. In particular, we present the form of conservation laws for the cases of pure spin, pure dilation and pure shear fluids. We also develop the concept of an incompressible hyperfluid and pay special attention to the case of a hypermomentum preserving hyperfluid. We also give a specific example on the emergence of the spin, dilation and shear currents through matter-connection couplings. In addition, starting from the generalized acceleration equation for the sc…
The Cosmological Impact of Intrinsic Alignment Model Choice for Cosmic Shear
我们考虑星系内禀排列对弱引力透镜暗能量约束的影响。在Hirata & Seljak（2010）的简要说明和Laszlo et al.（2011）的进一步解释之后，我们总结了IA线性排列模型的最新版本。我们显示宇宙学的偏见的暗能量状态方程参数w0和wa，如果IA被忽略会发生。我们发现，w0和wa都是灾难性的偏见，由一个绝对值，刚刚大于统一下的Fisher矩阵近似。这与早期IA实现的偏差大几倍形成对比。因此，毫无疑问，在今后的第三阶段试验和以后的试验中必须考虑到执行协定。我们使用了一个灵活的网格IA和星系偏置参数在以前的工作中使用，并调查会发生什么，如果宇宙使用最新的IA模型，但我们假设早期版本。我们发现，尽管两个IA模型之间的差异很大，网格的灵活性是足够的，以消除宇宙学的偏见，恢复正确的暗能量状态方程。在附录中，我们比较观察到的剪切功率谱，从以前流行的实施和解释的差异。
We forecast the linear bias for H${\rm α}$-emitting galaxies at high redshift. To simulate a Euclid-like and a WFIRST-like survey, we place galaxies into a large-volume dark matter halo lightcone by sampling a library of luminosity-dependent halo occupation distributions (HODs), which is constructed using a physically motivated galaxy formation model. We calibrate the dust attenuation in the lightcones such that they are able to reproduce the Hα luminosity function or the Hα cumulative number counts. The angle-averaged galaxy correlation function is computed for each survey in redshift slices …
We present a new cosmological analysis of the galaxy clusters in the Planck MMF3 cosmology sample with a cosmic microwave background (CMB) lensing calibration of the cluster masses. As demonstrated by Planck, galaxy clusters detected via the Sunyaev-Zel'dovich (SZ) effect offer a powerful way to constrain cosmological parameters such as $Ω_{\mathrm{m}}$ and $σ_8$. Determining the absolute cluster mass scale is, however, difficult, and some recent calibrations have yielded cosmological constraints in apparent tension with constraints in the $Λ$CDM model derived from the power spectra of the pri…
The well-developed separate universe technique enables accurate calibration of the response of any observable to an isotropic long-wavelength density fluctuation. The large-scale environment also hosts tidal modes that perturb all observables anisotropically. As in the separate universe, both the long tidal and density modes can be absorbed by an effective anisotropic background, on which the interaction and evolution of the short modes change accordingly. We further develop the tidal simulation method, including proper corrections to the second order Lagrangian perturbation theory (2LPT) to g…
Weak lensing peak abundance analyses have been applied in different surveys and demonstrated to be a powerful statistics in extracting cosmological information complementary to cosmic shear two-point correlation studies. Future large surveys with high number densities of galaxies enable tomographic peak analyses. Focusing on high peaks, we investigate quantitatively how the tomographic redshift binning can enhance the cosmological gains. We also perform detailed studies about the degradation of cosmological information due to photometric redshift (photo-z) errors. We show that for surveys with…
We present an emulator that accurately predicts the power spectrum of galaxies in redshift space as a function of cosmological parameters. Our emulator is based on a 2nd-order Lagrangian bias expansion that is displaced to Eulerian space using cosmological $N$-body simulations. Redshift space distortions are then imprinted using the non-linear velocity field of simulated particles and haloes. We build the emulator using a forward neural network trained with the simulations of the BACCO project, which covers an 8-dimensional parameter space including massive neutrinos and dynamical dark energy.…
We present differential double-copy relations between gluon and graviton three-point functions in (A)dS$_{d+1}$. We introduce a set of differential operators in (A)dS that naturally generalize on-shell kinematics of scattering amplitudes in flat space. This provides a way to construct (A)dS correlators by replacing the kinematic variables of amplitudes with the corresponding differential operators and suitably ordering them. By construction, the resulting correlators are manifestly conformally invariant, with the correct flat-space limit, and exhibit a differential double-copy structure.
