Showing 1–50 of 126 results for all: pengjie

CSST large-scale structure analysis pipeline: I. constructing reference mock galaxy redshift surveys

Authors: Yizhou Gu, Xiaohu Yang, Jiaxin Han, Yirong Wang, Qingyang Li, Zhenlin Tan, Wenkang Jiang, Yaru Wang, Jiaqi Wang, Antonios Katsianis, Xiaoju Xu, Haojie Xu, Wensheng Hong, Houjun Mo, Run Wen, Xianzhong Zheng, Feng Shi, Pengjie Zhang, Zhongxu Zhai, Chengze Liu, Wenting Wang, Ying Zu, Hong Guo, Youcai Zhang, Yi Lu , et al. (7 additional authors not shown)

Abstract: In this paper, we set out to construct a set of reference mock galaxy redshift surveys (MGRSs) for the future Chinese Space-station Survey Telescope (CSST) observation, where subsequent survey selection effects can be added and evaluated. This set of MGRSs is generated using the dark matter subhalos extracted from a high-resolution Jiutian $N$-body simulation of the standard $Λ$CDM cosmogony with… ▽ More In this paper, we set out to construct a set of reference mock galaxy redshift surveys (MGRSs) for the future Chinese Space-station Survey Telescope (CSST) observation, where subsequent survey selection effects can be added and evaluated. This set of MGRSs is generated using the dark matter subhalos extracted from a high-resolution Jiutian $N$-body simulation of the standard $Λ$CDM cosmogony with $Ω_m=0.3111$, $Ω_Λ=0.6889$, and $σ_8=0.8102$. The simulation has a boxsize of $1~h^{-1} {\rm Gpc}$, and consists of $6144^3$ particles with mass resolution $3.723 \times 10^{8} h^{-1} M_\odot $. In order to take into account the effect of redshift evolution, we first use all 128 snapshots in the Jiutian simulation to generate a light-cone halo/subhalo catalog. Next, galaxy luminosities are assigned to the main and subhalo populations using the subhalo abundance matching (SHAM) method with the DESI $z$-band luminosity functions at different redshifts. Multi-band photometries, as well as images, are then assigned to each mock galaxy using a 3-dimensional parameter space nearest neighbor sampling of the DESI LS observational galaxies and groups. Finally, the CSST and DESI LS survey geometry and magnitude limit cuts are applied to generate the required MGRSs. As we have checked, this set of MGRSs can generally reproduce the observed galaxy luminosity/mass functions within 0.1 dex for galaxies with $L > 10^8 L_\odot$ (or $M_* > 10^{8.5} M_\odot$) and within 1-$σ$ level for galaxies with $L < 10^8L_\odot$ (or $M_* < 10^{8.5} M_\odot$). Together with the CSST slitless spectra and redshifts for our DESI LS seed galaxies that are under construction, we will set out to test various slitless observational selection effects in subsequent probes. △ Less

Submitted 15 March, 2024; originally announced March 2024.

Comments: 13 pages, 9 figures, accepted for publication in MNRAS

The Jiao Tong University Spectroscopic Telescope Project

Authors: JUST Team, Chengze Liu, Ying Zu, Fabo Feng, Zhaoyu Li, Yu Yu, Hua Bai, Xiangqun Cui, Bozhong Gu, Yizhou Gu, Jiaxin Han, Yonghui Hou, Zhongwen Hu, Hangxin Ji, Yipeng Jing, Wei Li, Zhaoxiang Qi, Xianyu Tan, Cairang Tian, Dehua Yang, Xiangyan Yuan, Chao Zhai, Congcong Zhang, Jun Zhang, Haotong Zhang , et al. (6 additional authors not shown)

Abstract: The Jiao Tong University Spectroscopic Telescope (JUST) is a 4.4-meter f/6.0 segmentedmirror telescope dedicated to spectroscopic observations. The JUST primary mirror is composed of 18 hexagonal segments, each with a diameter of 1.1 m. JUST provides two Nasmyth platforms for placing science instruments. One Nasmyth focus fits a field of view of 10 arcmin and the other has an extended field of vie… ▽ More The Jiao Tong University Spectroscopic Telescope (JUST) is a 4.4-meter f/6.0 segmentedmirror telescope dedicated to spectroscopic observations. The JUST primary mirror is composed of 18 hexagonal segments, each with a diameter of 1.1 m. JUST provides two Nasmyth platforms for placing science instruments. One Nasmyth focus fits a field of view of 10 arcmin and the other has an extended field of view of 1.2 deg with correction optics. A tertiary mirror is used to switch between the two Nasmyth foci. JUST will be installed at a site at Lenghu in Qinghai Province, China, and will conduct spectroscopic observations with three types of instruments to explore the dark universe, trace the dynamic universe, and search for exoplanets: (1) a multi-fiber (2000 fibers) medium-resolution spectrometer (R=4000-5000) to spectroscopically map galaxies and large-scale structure; (2) an integral field unit (IFU) array of 500 optical fibers and/or a long-slit spectrograph dedicated to fast follow-ups of transient sources for multimessenger astronomy; (3) a high-resolution spectrometer (R~100000) designed to identify Jupiter analogs and Earth-like planets, with the capability to characterize the atmospheres of hot exoplanets. △ Less

Submitted 29 February, 2024; v1 submitted 22 February, 2024; originally announced February 2024.

Comments: 28 pages, 6 figures

Forecast of foreground cleaning strategies for AliCPT-1

Authors: Junzhou Zhang, Shamik Ghosh, Jiazheng Dou, Yang Liu, Siyu Li, Jiming Chen, Jiaxin Wang, Zhaoxuan Zhang, Jacques Delabrouille, Mathieu Remazeilles, Chang Feng, Bin Hu, Hao Liu, Larissa Santos, Pengjie Zhang, Wen Zhao, Le Zhang, Zhi-Qi Huang, Hong Li, Chao-Lin Kuo, Xinmin Zhang

Abstract: We report the test results of several independent foreground-cleaning pipelines used in the Ali CMB Polarization Telescope experiment (AliCPT-1), a high-altitude CMB imager in the Northern hemisphere with thousands of detectors dedicated to the search for a primordial CMB polarization $B$-mode signature. Based on simulated data from 4 detector modules and a single season of observation, which we r… ▽ More We report the test results of several independent foreground-cleaning pipelines used in the Ali CMB Polarization Telescope experiment (AliCPT-1), a high-altitude CMB imager in the Northern hemisphere with thousands of detectors dedicated to the search for a primordial CMB polarization $B$-mode signature. Based on simulated data from 4 detector modules and a single season of observation, which we refer to as DC1 data, we employ different and independent pipelines to examine the robustness and effectiveness of the estimates on foreground parameters and the primordial $B$-mode detection. The foreground-cleaning strategies used in the pipelines include the parametric method of template fitting (TF) and the non-parametric methods of the constrained internal linear combination (cILC), the analytical blind separation (ABS), and the generalized least squares (GLS). We examine the impact of possible foreground residuals on the estimate of the CMB tensor-to-scalar ratio ($r$) for each pipeline by changing the contamination components in the simulated maps and varying the foreground models and sky patches for various tests. According to the DC1 data with the simulation input value $r_{\rm true}=0.023$, the foreground residual contamination levels in the TF/ABS/cILC/GLS pipelines are well within the corresponding statistical errors at the $2σ$ level. For a selected patch with relatively stronger foreground contamination, all of the proposed pipelines perform robustly in testing. Furthermore, by utilizing the tension estimator, which helps identify significant residual foreground contamination in the detection of the primordial $B$-mode signal by quantifying the discrepancy between various $r$ measurements, we conclude that the presence of small foreground residuals does not lead to any significant inconsistency in the estimation of $r$. △ Less

Submitted 2 February, 2024; originally announced February 2024.

Momentum power spectrum of SDSS galaxies by massE cosmic ruler: 2.1x improvement in measure of growth rate

Authors: Yong Shi, Pengjie Zhang, Shude Mao, Qiusheng Gu

Abstract: Peculiar motion of galaxies probes the structure growth in the Universe. In this study we employ the galaxy stellar mass-binding energy (massE) relation with only two nuisance parameters to build the largest peculiar-velocity (PV) catalog to date, consisting of 229,890 ellipticals from the main galaxy sample (MGS) of the Sloan Digital Sky Survey (SDSS). We quantify the distribution of the massE-ba… ▽ More Peculiar motion of galaxies probes the structure growth in the Universe. In this study we employ the galaxy stellar mass-binding energy (massE) relation with only two nuisance parameters to build the largest peculiar-velocity (PV) catalog to date, consisting of 229,890 ellipticals from the main galaxy sample (MGS) of the Sloan Digital Sky Survey (SDSS). We quantify the distribution of the massE-based distances in individual narrow redshift bins (dz=0.005), and then estimate the PV of each galaxy based on its offset from the Gaussian mean of the distribution. As demonstrated with the Uchuu-SDSS mock data, the derived PV and momentum power spectra are insensitive to accurate calibration of the massE relation itself, enabling measurements out to a redshift of 0.2, well beyond the current limit of z=0.1 using other galaxy scaling laws. We then measure the momentum power spectrum and demonstrate that it remains almost unchanged if varying significantly the redshift bin size within which the distance is measured, as well as the intercept and slope of the massE relation, respectively. By fitting the spectra using the perturbation theory model with four free parameters, fσ8 is constrained to fσ8 =0.459+0.068-0.069 over Δz=0.02-0.2, 0.416+0.074-0.076 over Δz=0.02-0.1 and 0.526+0.133-0.143 over Δz=0.1-0.2. The error of fσ8 is 2.1 times smaller than that by the redshift space distortion (RSD) of the same sample. A Fisher-matrix forecast illustrates that the constraint on fσ8 from the massE-based PV can potentially exceed that from the stage-IV RSD in late universe (z<0.5). △ Less

Submitted 24 January, 2024; originally announced January 2024.

Comments: 20 pages, 25 figures, accepted for MNRAS

Forecast constraints on the baryonic feedback effect from the future kinetic Sunyaev-Zel'dovich effect detection

Authors: Yi Zheng, Pengjie Zhang

Abstract: The baryonic feedback effect is an important systematic error in the weak lensing (WL) analysis. It contributes partly to the $S_8$ tension in the literature. With the next generations of large scale structure (LSS) and CMB experiments, the high signal-to-noise kinetic Sunyaev-Zel'dovich (kSZ) effect detection can tightly constrain the baryon distribution in and around dark matter halos, and quant… ▽ More The baryonic feedback effect is an important systematic error in the weak lensing (WL) analysis. It contributes partly to the $S_8$ tension in the literature. With the next generations of large scale structure (LSS) and CMB experiments, the high signal-to-noise kinetic Sunyaev-Zel'dovich (kSZ) effect detection can tightly constrain the baryon distribution in and around dark matter halos, and quantify the baryonic effect in the weak lensing statistics. In this work, we apply the Fisher matrix technique to predict the future kSZ constraints on 3 kSZ-sensitive Baryon Correction Model (BCM) parameters. Our calculations show that, in combination with next generation LSS surveys, the 3rd generation CMB experiments such as AdvACT and Simon Observatory can constrain the matter power spectrum damping $S(k)$ to the precision of $σ_S(k)<0.8\%\sqrt{37.8{\rm Gpc}^3h^{-3}/V}$ at $k\lesssim 10h/$Mpc, where $V$ is the overlapped survey volume between the future LSS and CMB surveys. For the 4th generation CMB surveys such as CMB-S4 and CMB-HD, the constraint will be enhanced to $σ_S(k)<0.4\%\sqrt{37.8{\rm Gpc}^3h^{-3}/V}$. If extra-observations, e.g. X-ray detection and thermal SZ observation, can effectively fix the gas density profile slope parameter $δ$, the constraint on $S(k)$ will be further boosted to $σ_S(k)<0.3\%\sqrt{37.8{\rm Gpc}^3h^{-3}/V}$ and $σ_S(k)<0.1\%\sqrt{37.8{\rm Gpc}^3h^{-3}/V}$ for the 3rd and 4th generation CMB surveys. △ Less

Submitted 11 April, 2024; v1 submitted 7 January, 2024; originally announced January 2024.

Comments: 22 pages, 10 figures, minor revisions, JCAP accepted

Measuring the Hubble constant with coalescences of binary neutron star and neutron star-black hole: bright sirens \& dark sirens

Authors: Jiming Yu, Zhengyan Liu, Xiaohu Yang, Yu Wang, Pengjie Zhang, Xin Zhang, Wen Zhao

Abstract: The observations of gravitational wave (GW) provide us a new probe to study the universe. GW events can be used as standard sirens if their redshifts are measured. Normally, stardard sirens can be divided into bright/dark sirens according to whether the redshifts are measured by electromagnetic (EM) counterpart observations. Firstly, we investigate the capability of the 2.5-meter Wide-Field Survey… ▽ More The observations of gravitational wave (GW) provide us a new probe to study the universe. GW events can be used as standard sirens if their redshifts are measured. Normally, stardard sirens can be divided into bright/dark sirens according to whether the redshifts are measured by electromagnetic (EM) counterpart observations. Firstly, we investigate the capability of the 2.5-meter Wide-Field Survey Telescope (WFST) to take follow-up observations of kilonova counterparts. For binary neutron star (BNS) bright sirens, WFST is expected to observe 10-20 kilonovae per year in the second-generation (2G) GW detection era. As for neutron star-black hole (NSBH) mergers, when a BH spin is extremely high and the NS is stiff, the observation rate is $\sim10$ per year. Combining optical and GW observations, the bright sirens are expected to constrain the Hubble constant $H_0$ to $\sim2.8\%$ in five years of observations. As for dark sirens, tidal effects of neutron stars (NSs) during merging time provide us a cosmological model-independent approach to measure the redshifts of GW sources. Then we investigate the applications of tidal effects in redshift measurements. We find in 3G era, the host galaxy groups of around 45\% BNS mergers at $z<0.1$ can be identified through this method, if the EOS is ms1, which is roughly equivalent to the results from luminosity distant constraints. Therefore, tidal effect observations provide a reliable and cosmological model-independent method of identifying BNS mergers' host galaxy groups. Using this method, the BNS/NSBH dark sirens can constrain $H_0$ to 0.2\%/0.3\% over a five-year observation period. △ Less

Submitted 20 November, 2023; originally announced November 2023.

Comments: 26 pages, 13 figures, submitted to APJS, comments welcome

Journal ref: ApJS 270 24, 2024

Accurate Kappa Reconstruction Algorithm for masked shear catalog (AKRA)

Authors: Yuan Shi, Pengjie Zhang, Zeyang Sun, Yihe Wang

Abstract: Weak gravitational lensing is an invaluable tool for understanding fundamental cosmological physics. An unresolved issue in weak lensing cosmology is to accurately reconstruct the lensing convergence $κ$ maps from discrete shear catalog with survey masks, which the seminal Kaiser-Squire (KS) method is not designed to address. We present the Accurate Kappa Reconstruction Algorithm for masked shear… ▽ More Weak gravitational lensing is an invaluable tool for understanding fundamental cosmological physics. An unresolved issue in weak lensing cosmology is to accurately reconstruct the lensing convergence $κ$ maps from discrete shear catalog with survey masks, which the seminal Kaiser-Squire (KS) method is not designed to address. We present the Accurate Kappa Reconstruction Algorithm for masked shear catalog (AKRA) to address the issue of mask. AKRA is built upon the prior-free maximum likelihood mapmaking method (or the unbiased minimum variance linear estimator). It is mathematically robust in dealing with mask, numerically stable to implement, and practically effective in improving the reconstruction accuracy. Using simulated maps with mask fractions ranging from 10\% to 50\% and various mask shapes, we demonstrate that AKRA outperforms KS at both the map level and summary statistics such as the auto power spectrum $C_κ$ of the reconstructed map, its cross-correlation coefficient $r_\ell$ with the true $κ$ map, the scatter plot and the localization measure. Unlike the Wiener filter method, it adopts no priors on the signal power spectrum, and therefore avoids the Wiener filter related biases at both the map level and cross-correlation statistics. If we only use the reconstructed map in the unmasked regions, the reconstructed $C_κ$ is accurate to $1\%$ or better and $1-r_\ell \lesssim 1\%$ (excluding $\ell$ at the smallest scales investigated), even for extreme cases of mask fraction and shape. As the first step, the current version of AKRA only addresses the mask issue and therefore ignores complexities such as curved sky and inhomogeneous shape measurement noise. AKRA is capable of dealing with these issues straightfowrardly, and will be addressed in the next version. △ Less

Submitted 21 November, 2023; v1 submitted 1 November, 2023; originally announced November 2023.

Comments: 17 pages, 21 figures, To be submitted. Comments are welcome!

Weak Lensing Reconstruction by Counting DECaLS Galaxies

Authors: Jian Qin, Pengjie Zhang, Haojie Xu, Yu Yu, Ji Yao, Ruijie Ma, Huanyuan Shan

Abstract: Alternative to weak lensing measurements through cosmic shear, we present a weak lensing convergence $\hatκ$ map reconstructed through cosmic magnification effect in DECaLS galaxies of the DESI imaging surveys DR9. This is achieved by linearly weighing $12$ maps of galaxy number overdensity in different magnitude bins of $grz$ photometry bands. The weight is designed to eliminate the mean galaxy d… ▽ More Alternative to weak lensing measurements through cosmic shear, we present a weak lensing convergence $\hatκ$ map reconstructed through cosmic magnification effect in DECaLS galaxies of the DESI imaging surveys DR9. This is achieved by linearly weighing $12$ maps of galaxy number overdensity in different magnitude bins of $grz$ photometry bands. The weight is designed to eliminate the mean galaxy deterministic bias, minimize galaxy shot noise while maintaining the lensing convergence signal. We also perform corrections of imaging systematics in the galaxy number overdensity. The $\hatκ$ map has $8365$ deg$^2$ sky coverage. Given the low number density of DECaLS galaxies, the $\hatκ$ map is overwhelmed by shot noise and the map quality is difficult to evaluate using the lensing auto-correlation. Alternatively, we measure its cross-correlation with the cosmic shear catalogs of DECaLS galaxies of DESI imaging surveys DR8, which has $8365$ deg$^2$ overlap in sky coverage with the $\hatκ$ map. We detect a convergence-shear cross-correlation signal with $S/N\simeq 10$. The analysis also shows that the galaxy intrinsic clustering is suppressed by a factor $\mathcal{O}(10^2)$ and the residual galaxy clustering contamination in the $\hatκ$ map is consistent with zero. Various tests with different galaxy and shear samples, and the Akaike information criterion analysis all support the lensing detection. So is the imaging systematics corrections, which enhance the lensing signal detection by $\sim 30\%$. We discuss various issues for further improvement of the measurements. △ Less

Submitted 23 October, 2023; originally announced October 2023.

DESI Legacy Imaging Surveys Data Release 9: Cosmological Constraints from Galaxy Clustering and Weak Lensing using the Minimal Bias Model

Authors: Haojie Xu, Hekun Li, Jun Zhang, Xiaohu Yang, Pengjie Zhang, Min He, Yizhou Gu, Jian Qin, Zhaozhou Li, Antonios Katsianis, Ji Yao, Zhaoyu Wang, Yirong Wang, Liping Fu

Abstract: We present a tentative constraint on cosmological parameters $Ω_m$ and $σ_8$ from a joint analysis of galaxy clustering and galaxy-galaxy lensing from DESI Legacy Imaging Surveys Data Release 9 (DR9), covering approximately 10000 square degrees and spanning the redshift range of 0.1 to 0.9. To study the dependence of cosmological parameters on lens redshift, we divide lens galaxies into seven appr… ▽ More We present a tentative constraint on cosmological parameters $Ω_m$ and $σ_8$ from a joint analysis of galaxy clustering and galaxy-galaxy lensing from DESI Legacy Imaging Surveys Data Release 9 (DR9), covering approximately 10000 square degrees and spanning the redshift range of 0.1 to 0.9. To study the dependence of cosmological parameters on lens redshift, we divide lens galaxies into seven approximately volume-limited samples, each with an equal width in photometric redshift. To retrieve the intrinsic projected correlation function $w_{\rm p}(r_{\rm p})$ from the lens samples, we employ a novel method to account for redshift uncertainties. Additionally, we measured the galaxy-galaxy lensing signal $ΔΣ(r_{\rm p})$ for each lens sample, using source galaxies selected from the shear catalog by applying our \texttt{Fourier\_Quad} pipeline to DR9 images. We model these observables within the flat $Λ$CDM framework, employing the minimal bias model. To ensure the reliability of the minimal bias model, we apply conservative scale cuts: $r_{\rm p} > 8$ and $12 ~h^{-1}{\rm Mpc}$, for $w_{\rm p}(r_{\rm p})$ and $ΔΣ(r_{\rm p})$, respectively. Our findings suggest a mild tendency that $S_8 \equiv σ_8 \sqrt{Ω_m/0.3} $ increases with lens redshift, although this trend is only marginally significant. When we combine low redshift samples, the value of $S_8$ is determined to be $0.84 \pm 0.02$, consistent with the Planck results but significantly higher than the 3$\times$ 2pt analysis by 2-5$σ$. Despite the fact that further refinements in measurements and modeling could improve the accuracy of our results, the consistency with standard values demonstrates the potential of our method for more precise and accurate cosmology in the future. △ Less

Submitted 20 November, 2023; v1 submitted 4 October, 2023; originally announced October 2023.

Comments: slightly different with the published version

Journal ref: SCIENCE CHINA Physics, Mechanics & Astronomy, Volume 66, Issue 12: 129811 (2023)

A method of weak lensing reconstruction through cosmic magnification with multi-band photometry information

Authors: Ruijie Ma, Pengjie Zhang, Yu Yu, Jian Qin

Abstract: Weak gravitational lensing induces flux dependent fluctuations in the observed galaxy number density distribution. This cosmic magnification (magnification bias) effect in principle enables lensing reconstruction alternative to cosmic shear and CMB lensing. However, the intrinsic galaxy clustering, which otherwise overwhelms the signal, has hindered its application. Through a scaling relation foun… ▽ More Weak gravitational lensing induces flux dependent fluctuations in the observed galaxy number density distribution. This cosmic magnification (magnification bias) effect in principle enables lensing reconstruction alternative to cosmic shear and CMB lensing. However, the intrinsic galaxy clustering, which otherwise overwhelms the signal, has hindered its application. Through a scaling relation found by principal component analysis of the galaxy clustering in multi-band photometry space, we design a minimum variance linear estimator to suppress the intrinsic galaxy clustering and to reconstruct the lensing convergence map. In combination of the CosmoDC2 galaxy mock and the CosmicGrowth simulation, we test this proposal for a LSST-like galaxy survey with $ugrizY$ photometry bands. The scaling relation holds excellently at multipole $\ell<10^3$, and remains reasonably well to $\ell\sim 3000$. The linear estimator efficiently suppresses the galaxy intrinsic clustering, by a factor of $\sim 10^2$. For galaxies in the photo-z range $0.8<z_κ<1.2$, the reconstructed convergence map is cosmic variance limited per $\ell$ mode at $\ell<10^2$, and shot noise limited at $\ell>= 200$. Its cross-correlation with cosmic shear of galaxies can achieve $S/N >= 200$. When the source redshift of cosmic shear galaxies $z_γ<z_κ$, the systematic error is negligible at all investigated scales ($\ell<3000$). When $z_γ\geq z_κ$, the systematic error caused by the residual intrinsic galaxy clustering becomes non-negligible. We discuss possible mitigation of the residual intrinsic galaxy clustering required for accurate measurement at $\ell>10^3$. This work further demonstrates the potential of lensing measurement through cosmic magnification to enhance the weak lensing cosmology. △ Less

Submitted 30 November, 2023; v1 submitted 26 June, 2023; originally announced June 2023.

Comments: 9 pages, 12 figures, accepted to MNRAS

Detector induced anisotropies on the angular distribution of gravitational wave sources and opportunities of constraining horizon scale anisotropies

Authors: Mingzheng Li, Pengjie Zhang, Wen Zhao

Abstract: The cosmological principle has been verified using electromagnetic (EM) observations. However its verification with high accuracy is challenging due to various foregrounds and selection effects, and possible violation of the cosmological principle has been reported in the literature. In contrast, gravitational wave (GW) observations are free of these foregrounds and related selection biases. This… ▽ More The cosmological principle has been verified using electromagnetic (EM) observations. However its verification with high accuracy is challenging due to various foregrounds and selection effects, and possible violation of the cosmological principle has been reported in the literature. In contrast, gravitational wave (GW) observations are free of these foregrounds and related selection biases. This may enable future GW experiments to test the cosmological principle robustly with full sky distribution of millions of standard bright/dark sirens. However, the sensitivities of GW detectors are highly anisotropic, resulting in significant instrument induced anisotropies in the observed GW catalog. We investigate these instrumental effects for 3rd generation detector networks in term of multipoles $a_{\ell m}$ of the observed GW source distribution, using Monte Carlo simulations. (1) We find that the instrument induced anisotropy primarily exists at the $m=0$ modes on large scales ($\ell \lesssim 10$), with amplitude $\langle |a_{\ell 0}|^2 \rangle \sim 10^{-3}$ for two detectors (ET-CE) and $\sim 10^{-4}$ for three detectors (ET-2CE). This anisotropy is correlated with the sky distribution of signal-to-noise ratio (SNR) and localization accuracy. Such anisotropy sets a lower limit on the detectable cosmological $a_{\ell 0}$. (2) However, we find that the instrument induced anisotropy is efficiently canceled by rotation of the Earth in $m\neq 0$ components of $a_{\ell m}$. Therefore $a_{\ell m}$ ($m\neq 0$) are clean windows to detect cosmological anisotropies. (3) We investigate the capability of 3rd generation GW experiments to measure the cosmic dipole. Through Monte Carlo simulations, we find that cosmic dipole with an amplitude of $\sim 10^{-2}$ reported in the literature can be detected/ruled out by ET-CE and ET-2CE robustly, through the measurement of $a_{11}$. △ Less

Submitted 13 September, 2023; v1 submitted 25 May, 2023; originally announced May 2023.

Comments: 7 pages, 6 figures, submitted to MNRAS

Journal ref: Monthly Notices of the Royal Astronomical Society, Volume 525, Issue 4, November 2023, Pages 5180-5186

Fisher forecast for the BAO measurements from the CSST spectroscopic and photometric galaxy clustering

Authors: Zhejie Ding, Yu Yu, Pengjie Zhang

Abstract: The China Space Station Telescope (CSST) is a forthcoming Stage IV galaxy survey. It will simultaneously undertake the photometric redshift (photo-z) and slitless spectroscopic redshift (spec-z) surveys mainly for weak lensing and galaxy clustering studies. The two surveys cover the same sky area and overlap on the redshift range. At $z>1$, due to the sparse number density of the spec-z sample, it… ▽ More The China Space Station Telescope (CSST) is a forthcoming Stage IV galaxy survey. It will simultaneously undertake the photometric redshift (photo-z) and slitless spectroscopic redshift (spec-z) surveys mainly for weak lensing and galaxy clustering studies. The two surveys cover the same sky area and overlap on the redshift range. At $z>1$, due to the sparse number density of the spec-z sample, it limits the constraints on the scale of baryon acoustic oscillations (BAO). By cross-correlating the spec-z sample with the high density photo-z sample, we can effectively enhance the constraints on the angular diameter distances $D_A(z)$ from the BAO measurement. Based on the Fisher matrix, we forecast a $\geq$ 30 per cent improvement on constraining $D_A(z)$ from the joint analysis of the spec-z and cross galaxy power spectra at $1.0<z<1.2$. Such improvement is generally robust against different systematic effects including the systematic noise and the redshift success rate of the spec-z survey, as well as the photo-z error. We also show the BAO constraints from other Stage-IV spectroscopic surveys for the comparison with CSST. Our study can be a reference for the future BAO analysis on real CSST data. The methodology can be applied to other surveys with spec-z and photo-z data in the same survey volume. △ Less

Submitted 23 November, 2023; v1 submitted 30 April, 2023; originally announced May 2023.

Comments: 13 pages, 11 figures; Published by MNRAS

Journal ref: MNRAS, 527 (2023) 3728-3740

Principal Component Analysis of Galaxy Clustering in Hyperspace of Galaxy Properties

Authors: Shuren Zhou, Pengjie Zhang, Ziyang Chen

Abstract: Ongoing and upcoming galaxy surveys are providing precision measurements of galaxy clustering. However a major obstacle in its cosmological application is the stochasticity in the galaxy bias. We explore whether the principal component analysis (PCA) of galaxy correlation matrix in hyperspace of galaxy properties (e.g. magnitude and color) can reveal further information on mitigating this issue. B… ▽ More Ongoing and upcoming galaxy surveys are providing precision measurements of galaxy clustering. However a major obstacle in its cosmological application is the stochasticity in the galaxy bias. We explore whether the principal component analysis (PCA) of galaxy correlation matrix in hyperspace of galaxy properties (e.g. magnitude and color) can reveal further information on mitigating this issue. Based on the hydrodynamic simulation TNG300-1, we analyze the cross power spectrum matrix of galaxies in the magnitude and color space of multiple photometric bands. (1) We find that the first principal component $E_i^{(1)}$ is an excellent proxy of the galaxy deterministic bias $b_{D}$, in that $E_i^{(1)}=\sqrt{P_{mm}/λ(1)}b_{D,i}$. Here $i$ denotes the $i$-th galaxy sub-sample. $λ^{(1)}$ is the largest eigenvalue and $P_{mm}$ is the matter power spectrum. We verify that this relation holds for all the galaxy samples investigated, down to $k\sim 2h/$Mpc. Since $E_i^{(1)}$ is a direct observable, we can utilize it to design a linear weighting scheme to suppress the stochasticity in the galaxy-matter relation. For an LSST-like magnitude limit galaxy sample, the stochasticity $\mathcal{S}\equiv 1-r^2$ can be suppressed by a factor of $\ga 2$ at $k=1h/$Mpc. This reduces the stochasticity-induced systematic error in the matter power spectrum reconstruction combining galaxy clustering and galaxy-galaxy lensing from $\sim 12\%$ to $\sim 5\%$ at $k=1h/$Mpc. (2) We also find that $\mathcal{S}$ increases monotonically with $f_λ$ and $f_{λ^2}$. $f_{λ,λ^2}$ quantify the fractional contribution of other eigenmodes to the galaxy clustering and are direct observables. Therefore the two provide extra information on mitigating galaxy stochasticity. △ Less

Submitted 14 June, 2023; v1 submitted 23 April, 2023; originally announced April 2023.

CSST WL preparation I: forecast the impact from non-Gaussian covariances and requirements on systematics-control

Authors: Ji Yao, Huanyuan Shan, Ran Li, Youhua Xu, Dongwei Fan, Dezi Liu, Pengjie Zhang, Yu Yu, Chengliang Wei, Bin Hu, Nan Li, Zuhui Fan, Haojie Xu, Wuzheng Guo

Abstract: The precise estimation of the statistical errors and accurate removal of the systematical errors are the two major challenges for the stage IV cosmic shear surveys. We explore their impact for the China Space-Station Telescope (CSST) with survey area $\sim17,500°^2$ up to redshift $\sim4$. We consider statistical error contributed from Gaussian covariance, connected non-Gaussian covariance and sup… ▽ More The precise estimation of the statistical errors and accurate removal of the systematical errors are the two major challenges for the stage IV cosmic shear surveys. We explore their impact for the China Space-Station Telescope (CSST) with survey area $\sim17,500°^2$ up to redshift $\sim4$. We consider statistical error contributed from Gaussian covariance, connected non-Gaussian covariance and super-sample covariance. We find the non-Gaussian covariances, which is dominated by the super-sample covariance, can largely reduce the signal-to-noise of the two-point statistics for CSST, leading to a $\sim1/3$ loss in the figure-of-merit for the matter clustering properties ($σ_8-Ω_m$ plane) and $1/6$ in the dark energy equation-of-state ($w_0-w_a$ plane). We further put requirements of systematics-mitigation on: intrinsic alignment of galaxies, baryonic feedback, shear multiplicative bias, and bias in the redshift distribution, for an unbiased cosmology. The $10^{-2}$ to $10^{-3}$ level requirements emphasize strong needs in related studies, to support future model selections and the associated priors for the nuisance parameters. △ Less

Submitted 16 November, 2023; v1 submitted 10 April, 2023; originally announced April 2023.

Comments: accepted by MNRAS

Forecasts of CMB lensing reconstruction of AliCPT-1 from the foreground cleaned polarization data

Authors: Jiakang Han, Bin Hu, Shamik Ghosh, Siyu Li, Jiazheng Dou, Jacques Delabrouille, Jing Jin, Hong Li, Yang Liu, Mathieu Remazeilles, Wen Zhao, Pengjie Zhang, Zheng-Wei Li, Cong-Zhan Liu, Yong-jie Zhang, Chao-Lin Kuo, Xinmin Zhang

Abstract: Cosmic microwave background radiation (CMB) observations are unavoidably contaminated by emission from various extra-galactic foregrounds, which must be removed to obtain reliable measurements of the cosmological signal. In this paper, we demonstrate CMB lensing reconstruction in AliCPT-1 after foreground removal, combine the two bands of AliCPT-1 (90 and 150~GHz) with Planck HFI bands (100, 143,… ▽ More Cosmic microwave background radiation (CMB) observations are unavoidably contaminated by emission from various extra-galactic foregrounds, which must be removed to obtain reliable measurements of the cosmological signal. In this paper, we demonstrate CMB lensing reconstruction in AliCPT-1 after foreground removal, combine the two bands of AliCPT-1 (90 and 150~GHz) with Planck HFI bands (100, 143, 217 and 353~GHz) and with the WMAP-K band (23~GHz). In order to balance contamination by instrumental noise and foreground residual bias, we adopt the Needlet Internal Linear Combination (NILC) method to clean the E-map and the constrained Internal Linear Combination (cILC) method to clean the B-map. The latter utilizes additional constraints on average frequency scaling of the dust and synchrotron to remove foregrounds at the expense of somewhat noisier maps. Assuming 4 modules observing 1 season from simulation data, the resulting effective residual noise in E- and B-map are roughly $15~μ{\rm K}\cdot{\rm arcmin}$ and $25~μ{\rm K}\cdot{\rm arcmin}$, respectively. As a result, the CMB lensing reconstruction signal-to-noise ratio (SNR) from polarization data is about SNR$\,\approx\,$4.5. This lensing reconstruction capability is comparable to that of other stage-III small aperture millimeter CMB telescopes. △ Less

Submitted 10 March, 2023; originally announced March 2023.

Comments: 12 pages, 6 figures

KiDS-1000: cross-correlation with Planck cosmic microwave background lensing and intrinsic alignment removal with self-calibration

Authors: Ji Yao, Huanyuan Shan, Pengjie Zhang, Xiangkun Liu, Catherine Heymans, Benjamin Joachimi, Marika Asgari, Maciej Bilicki, Hendrik Hildebrandt, Konrad Kuijken, Tilman Tröster, Jan Luca van den Busch, Angus Wright, Ziang Yan

Abstract: Galaxy shear - cosmic microwave background (CMB) lensing convergence cross-correlations contain additional information on cosmology to auto-correlations. While being immune to certain systematic effects, they are affected by the galaxy intrinsic alignments (IA). This may be responsible for the reported low lensing amplitude of the galaxy shear $\times$ CMB convergence cross-correlations, compared… ▽ More Galaxy shear - cosmic microwave background (CMB) lensing convergence cross-correlations contain additional information on cosmology to auto-correlations. While being immune to certain systematic effects, they are affected by the galaxy intrinsic alignments (IA). This may be responsible for the reported low lensing amplitude of the galaxy shear $\times$ CMB convergence cross-correlations, compared to the standard Planck $Λ$CDM (cosmological constant and cold dark matter) cosmology prediction. In this work, we investigate how IA affects the Kilo-Degree Survey (KiDS) galaxy lensing shear - Planck CMB lensing convergence cross-correlation and compare it to previous treatments with or without IA taken into consideration. More specifically, we compare marginalization over IA parameters and the IA self-calibration (SC) method (with additional observables defined only from the source galaxies) and prove that SC can efficiently break the degeneracy between the CMB lensing amplitude $A_{\rm lens}$ and the IA amplitude $A_{\rm IA}$. We further investigate how different systematics affect the resulting $A_{\rm IA}$ and $A_{\rm lens}$, and validate our results with the MICE2 simulation. We find that by including the SC method to constrain IA, the information loss due to the degeneracy between CMB lensing and IA is strongly reduced. The best-fit values are $A_{\rm lens}=0.84^{+0.22}_{-0.22}$ and $A_{\rm IA}=0.60^{+1.03}_{-1.03}$, while different angular scale cuts can affect $A_{\rm lens}$ by $\sim10\%$. We show that appropriate treatment of the boost factor, cosmic magnification, and photometric redshift modeling is important for obtaining the correct IA and cosmological results. △ Less

Submitted 10 April, 2023; v1 submitted 31 January, 2023; originally announced January 2023.

Comments: match version accepted by A&A

Journal ref: A&A 673, A111 (2023)

DESI and DECaLS (D&D): galaxy-galaxy lensing measurements with 1% survey and its forecast

Authors: Ji Yao, Huanyuan Shan, Pengjie Zhang, Eric Jullo, Jean-Paul Kneib, Yu Yu, Ying Zu, David Brooks, Axel de la Macorra, Peter Doel, Andreu Font-Ribera, Satya Gontcho A Gontcho, Theodore Kisner, Martin Landriau, Aaron Meisner, Ramon Miquel, Jundan Nie, Claire Poppett, Francisco Prada, Michael Schubnell, Mariana Vargas Magana, Zhimin Zhou

Abstract: The shear measurement from DECaLS (Dark Energy Camera Legacy Survey) provides an excellent opportunity for galaxy-galaxy lensing study with DESI (Dark Energy Spectroscopic Instrument) galaxies, given the large ($\sim 9000$ deg$^2$) sky overlap. We explore this potential by combining the DESI 1\% survey and DECaLS DR8. With $\sim 106$ deg$^2$ sky overlap, we achieve significant detection of galaxy-… ▽ More The shear measurement from DECaLS (Dark Energy Camera Legacy Survey) provides an excellent opportunity for galaxy-galaxy lensing study with DESI (Dark Energy Spectroscopic Instrument) galaxies, given the large ($\sim 9000$ deg$^2$) sky overlap. We explore this potential by combining the DESI 1\% survey and DECaLS DR8. With $\sim 106$ deg$^2$ sky overlap, we achieve significant detection of galaxy-galaxy lensing for BGS and LRG as lenses. Scaled to the full BGS sample, we expect the statistical errors to improve from $18(12)\%$ to a promising level of $2(1.3)\%$ at $θ>8^{'}(<8^{'})$. This brings stronger requirements for future systematics control. To fully realize such potential, we need to control the residual multiplicative shear bias $|m|<0.01$ and the bias in the mean redshift $|Δz|<0.015$. We also expect significant detection of galaxy-galaxy lensing with DESI LRG/ELG full samples as lenses, and cosmic magnification of ELG through cross-correlation with low-redshift DECaLS shear. {If such systematical error control can be achieved,} we find the advantages of DECaLS, comparing with KiDS (Kilo Degree Survey) and HSC (Hyper-Suprime Cam), are at low redshift, large-scale, and in measuring the shear-ratio (to $σ_R\sim 0.04$) and cosmic magnification. △ Less

Submitted 31 January, 2023; originally announced January 2023.

Comments: submitted to MNRAS

An unbiased method of measuring the ratio of two data sets

Authors: Zeyang Sun, Pengjie Zhang, Fuyu Dong, Ji Yao, Huanyuan Shan, Eric Jullo, Jean-Paul Kneib, Boyan Yin

Abstract: In certain cases of astronomical data analysis, the meaningful physical quantity to extract is the ratio $R$ between two data sets. Examples include the lensing ratio, the interloper rate in spectroscopic redshift samples, the decay rate of gravitational potential and $E_G$ to test gravity. However, simply taking the ratio of the two data sets is biased, since it renders (even statistical) errors… ▽ More In certain cases of astronomical data analysis, the meaningful physical quantity to extract is the ratio $R$ between two data sets. Examples include the lensing ratio, the interloper rate in spectroscopic redshift samples, the decay rate of gravitational potential and $E_G$ to test gravity. However, simply taking the ratio of the two data sets is biased, since it renders (even statistical) errors in the denominator into systematic errors in $R$. Furthermore, it is not optimal in minimizing statistical errors of $R$. Based on Bayesian analysis and the usual assumption of Gaussian error in the data, we derive an analytical expression of the posterior PDF $P(R)$. This result enables fast and unbiased $R$ measurement, with minimal statistical errors. Furthermore, it relies on no underlying model other than the proportionality relation between the two data sets. Even more generally, it applies to the cases where the proportionality relation holds for the underlying physics/statistics instead of the two data sets directly. It also applies to the case of multiple ratios ($R\rightarrow {\bf R}=(R_1,R_2,\cdots)$). We take the lensing ratio as an example to demonstrate our method. We take lenses as DESI imaging survey galaxies, and sources as DECaLS cosmic shear and \emph{Planck} CMB lensing. We restrict the analysis to the ratio between CMB lensing and cosmic shear. The resulting $P(R)$, for multiple lens-shear pairs, are all nearly Gaussian. The S/N of measured $R$ ranges from $4.9$ to $8.4$. We perform several tests to verify the robustness of the above result. △ Less

Submitted 17 June, 2023; v1 submitted 24 October, 2022; originally announced October 2022.

Comments: 13 pages, 9 figures. Codes available at https://github.com/Ze-yangSUN/Ratio_method

Using angular two-point correlations to self-calibrate the photometric redshift distributions of DECaLS DR9

Authors: Haojie Xu, Pengjie Zhang, Hui Peng, Yu Yu, Le Zhang, Ji Yao, Jian Qin, Zeyang Sun, Min He, Xiaohu Yang

Abstract: Calibrating the redshift distributions of photometric galaxy samples is essential in weak lensing studies. The self-calibration method combines angular auto- and cross-correlations between galaxies in multiple photometric redshift (photo-$z$) bins to reconstruct the scattering rates matrix between redshift bins. In this paper, we test a recently proposed self-calibration algorithm using the DECaLS… ▽ More Calibrating the redshift distributions of photometric galaxy samples is essential in weak lensing studies. The self-calibration method combines angular auto- and cross-correlations between galaxies in multiple photometric redshift (photo-$z$) bins to reconstruct the scattering rates matrix between redshift bins. In this paper, we test a recently proposed self-calibration algorithm using the DECaLS Data Release 9 and investigate to what extent the scattering rates are determined. We first mitigate the spurious angular correlations due to imaging systematics by a machine learning based method. We then improve the algorithm for $χ^2$ minimization and error estimation. Finally, we solve for the scattering matrices, carry out a series of consistency tests and find reasonable agreements: (1) finer photo-$z$ bins return a high-resolution scattering matrix, and it is broadly consistent with the low-resolution matrix from wider bins; (2) the scattering matrix from the Northern Galactic Cap is almost identical to that from Southern Galactic Cap; (3) the scattering matrices are in reasonable agreement with those constructed from the power spectrum and the weighted spectroscopic subsample. We also evaluate the impact of cosmic magnification. Although it changes little the diagonal elements of the scattering matrix, it affects the off-diagonals significantly. The scattering matrix also shows some dependence on scale cut of input correlations, which may be related to a known numerical degeneracy between certain scattering pairs. This work demonstrates the feasibility of the self-calibration method in real data and provides a practical alternative to calibrate the redshift distributions of photometric samples. △ Less

Submitted 5 February, 2023; v1 submitted 8 September, 2022; originally announced September 2022.

Comments: Matched with publish version

The first direct measurement of gravitational potential decay rate at cosmological scales and improved dark energy constraint

Authors: Fuyu Dong, Pengjie Zhang, Zeyang Sun, Changbom Park

Abstract: The integrated Sachs-Wolfe (ISW) effect probes the decay rate ($DR$) of large scale gravitational potential and therefore provides unique constraint on dark energy (DE). However its constraining power is degraded by the ISW measurement, which relies on cross-correlating with the large scale structure (LSS) and suffers from uncertainties in galaxy bias and matter clustering. In combination with len… ▽ More The integrated Sachs-Wolfe (ISW) effect probes the decay rate ($DR$) of large scale gravitational potential and therefore provides unique constraint on dark energy (DE). However its constraining power is degraded by the ISW measurement, which relies on cross-correlating with the large scale structure (LSS) and suffers from uncertainties in galaxy bias and matter clustering. In combination with lensing-LSS cross-correlation, $DR$ can be isolated in a way free of uncertainties in galaxy bias and matter clustering. We applied this proposal to the combination of the DR8 galaxy catalogue of DESI imaging surveys and Planck cosmic microwave background (CMB) maps. We achieved the first $DR$ measurement, with a total significance of $3.2σ$. We verified the measurements at three redshift bins ($[0.2,0.4)$, $[0.4, 0.6)$, $[0.6,0.8]$), with two LSS tracers (the "low-density points" and the conventional galaxy positions). Despite its relatively low S/N, the addition of $DR$ significantly improves dark energy constraints, over SDSS baryon acoustic oscillation (BAO) data alone or Pantheon supernovae (SN) compilation alone. For flat $w$CDM cosmology, the improvement in the precision of $Ω_m$ is a factor of 1.8 over BAO and 1.5 over SN. For the DE equation of state $w$, the improvement factor is 1.3 over BAO and 1.4 over SN. These improvements demonstrate $DR$ as a useful cosmological probe, and therefore we advocate its usage in future cosmological analysis. △ Less

Submitted 29 October, 2022; v1 submitted 10 June, 2022; originally announced June 2022.

Comments: 9 pages, 6 figures

Journal ref: ApJ,938,72 (year 2022)

Performance forecasts for the primordial gravitational wave detection pipelines for AliCPT-1

Authors: Shamik Ghosh, Yang Liu, Le Zhang, Siyu Li, Junzhou Zhang, Jiaxin Wang, Jiazheng Dou, Jiming Chen, Jacques Delabrouille, Mathieu Remazeilles, Chang Feng, Bin Hu, Zhi-Qi Huang, Hao Liu, Larissa Santos, Pengjie Zhang, Zhaoxuan Zhang, Wen Zhao, Hong Li, Xinmin Zhang

Abstract: AliCPT is the first Chinese cosmic microwave background (CMB) experiment which will make the most precise measurements of the CMB polarization in the northern hemisphere. The key science goal for AliCPT is the detection of primordial gravitational waves (PGWs). It is well known that an epoch of cosmic inflation, in the very early universe, can produce PGWs, which leave an imprint on the CMB in for… ▽ More AliCPT is the first Chinese cosmic microwave background (CMB) experiment which will make the most precise measurements of the CMB polarization in the northern hemisphere. The key science goal for AliCPT is the detection of primordial gravitational waves (PGWs). It is well known that an epoch of cosmic inflation, in the very early universe, can produce PGWs, which leave an imprint on the CMB in form of odd parity $B$-mode polarization. In this work, we study the performance of the component separation and parameter estimation pipelines in context of constraining the value of the tensor-to-scalar ratio. Based on the simulated data for one observation season, we compare five different pipelines with different working principles. Three pipelines perform component separation at map or spectra level before estimating $r$ from the cleaned spectra, while the other two pipelines performs a global fit for both foreground parameters and $r$. We also test different methods to account for the effects of time stream filtering systematics. This work shows that our pipelines provide consistent and robust constraints on the tensor-to-scalar ratio and a consistent sensitivity $σ(r) \sim 0.02$. This showcases the potential of precise $B$-mode polarization measurement with AliCPT-1. AliCPT will provide a powerful opportunity to detect PGWs, which is complementary with various ground-based CMB experiments in the southern hemisphere. △ Less

Submitted 13 October, 2022; v1 submitted 29 May, 2022; originally announced May 2022.

Comments: 34 pages, 10 figs, 5 tables, JCAP in press

Journal ref: JCAP 10, 063 (2022)

Forecasts on CMB lensing observations with AliCPT-1

Authors: Jinyi Liu, Zeyang Sun, Jiakang Han, Julien Carron, Jacques Delabrouille, Siyu Li, Yang Liu, Jing Jin, Shamik Ghosh, Bin Yue, Pengjie Zhang, Chang Feng, Zhi-Qi Huang, Hao Liu, Yi-Wen Wu, Le Zhang, Zi-Rui Zhang, Wen Zhao, Bin Hu, Hong Li, Xinmin Zhang

Abstract: AliCPT-1 is the first Chinese CMB experiment aiming for high precision measurement of Cosmic Microwave Background B-mode polarization. The telescope, currently under deployment in Tibet, will observe in two frequency bands centered at 90 and 150 GHz. We forecast the CMB lensing reconstruction, lensing-galaxy as well as lensing-CIB (Cosmic Infrared Background) cross correlation signal-to-noise rati… ▽ More AliCPT-1 is the first Chinese CMB experiment aiming for high precision measurement of Cosmic Microwave Background B-mode polarization. The telescope, currently under deployment in Tibet, will observe in two frequency bands centered at 90 and 150 GHz. We forecast the CMB lensing reconstruction, lensing-galaxy as well as lensing-CIB (Cosmic Infrared Background) cross correlation signal-to-noise ratio (SNR) for AliCPT-1. We consider two stages with different integrated observation time, namely "4 module*yr" (first stage) and "48 module*yr" (final stage). For lensing reconstruction, we use three different quadratic estimators, namely temperature-only, polarization-only and minimum-variance estimators, using curved sky geometry. We take into account the impact of inhomogeneous hit counts as well as of the mean-field bias due to incomplete sky coverage. In the first stage, our results show that the 150 GHz channel is able to measure the lensing signal at $15σ$ significance with the minimum-variance estimator. In the final stage, the measurement significance will increase to $31σ$. We also combine the two frequency data in the harmonic domain to optimize the SNR. Our result show that the coadding procedure can significantly reduce the reconstruction bias in the multiple range l>800. Thanks to the high quality of the polarization data in the final stage of AliCPT-1, the EB estimator will dominate the lensing reconstruction in this stage. We also estimate the SNR of cross-correlations between AliCPT-1 CMB lensing and other tracers of the large scale structure of the universe. For its cross-correlation with DESI galaxies/quasars, we report the cross-correlation SNR = 10-20 for the 4 redshift bins at 0.05<z<2.1. In the first stage, the total SNR is about $32$. In the final stage, the lensing-galaxy cross-correlation can reach SNR=52. △ Less

Submitted 18 April, 2022; originally announced April 2022.

Comments: 18 pages, 8 figures, 3 tables

Thermal energy census with the Sunyaev-Zel'dovich effect of DESI galaxy clusters/groups and its implication on the weak lensing power spectrum

Authors: Ziyang Chen, Pengjie Zhang, Xiaohu Yang

Abstract: We carry out a thermal energy census of hot baryons at $z < 1$, by cross-correlating the \emph{Planck} MILCA y-map with 0.8 million clusters/groups selected from the Yang et.al (2021) catalog. The thermal Sunyaev-Zel'dovich (tSZ) effect around these clusters/groups are reliably obtained, which enables us to make our model constraints based on one-halo (1h) and two-halo (2h) contributions, respecti… ▽ More We carry out a thermal energy census of hot baryons at $z < 1$, by cross-correlating the \emph{Planck} MILCA y-map with 0.8 million clusters/groups selected from the Yang et.al (2021) catalog. The thermal Sunyaev-Zel'dovich (tSZ) effect around these clusters/groups are reliably obtained, which enables us to make our model constraints based on one-halo (1h) and two-halo (2h) contributions, respectively. (1) The total measurement S/N of the one-halo term is 63. We constrain the $Y$-$M$ relation over the halo mass range of $10^{13}$-$10^{15} M_\odot/h$, and find $Y\propto M^α$ with $α= 1.8$ at $z=0.14$ ($α=2.1$ at $z=0.75$). The total thermal energy of gas bound to clusters/groups increases from $0.1\ \rm meV/cm^3$ at $z=0.14$ to $0.22\ \rm meV/cm^3$ at $z=0.75$. (2) The two-halo term is used to constrain the bias-weighted electron pressure $\langle b_yP_e \rangle$. We find that $\langle b_yP_e \rangle$ (in unit of $\rm meV/cm^3$) increases from $0.24\pm 0.02$ at $z=0.14$ to $0.45\pm 0.02$ at $z=0.75$. These results lead to several implications. (i) The hot gas fraction $f_{\rm gas}$ in clusters/groups monotonically increase with halo mass, where $f_{\rm gas}$ of a $10^{14} M_\odot/h$ halo is $\sim 50\%$ ($25\%$) of the cosmic mean at $z=0.14\ (0.75)$. (ii) By comparing the 1h- and 2h-terms, we obtain tentative constraint on the thermal energy of unbound gas. (iii) The above results lead to significant suppression of matter and weak lensing power spectrum at small scales. These implications are important for astrophysics and cosmology, and we will further investigate them with improved data and gas modeling. △ Less

Submitted 25 June, 2023; v1 submitted 29 January, 2022; originally announced January 2022.

Comments: Re-analyzed with the updated DESI group catalog. Major results remain unchanged. Accepted for publication in ApJ

About One-point Statistics of the Ratio of Two Fourier-transformed Cosmic Fields and an Application

Authors: Ming Li, Jun Pan, Pengjie Zhang, Jie Wang, Longlong Feng, Liang Gao, Xi Kang, Guoliang Li, Weipeng Lin, Haihui Wang

Abstract: The Fourier transformation is an effective and efficient operation of Gaussianization at the one-point level. Using a set of N-body simulation data, we verified that the one-point distribution functions of the dark matter momentum divergence and density fields closely follow complex Gaussian distributions. The one-point distribution function of the quotient of two complex Gaussian variables is int… ▽ More The Fourier transformation is an effective and efficient operation of Gaussianization at the one-point level. Using a set of N-body simulation data, we verified that the one-point distribution functions of the dark matter momentum divergence and density fields closely follow complex Gaussian distributions. The one-point distribution function of the quotient of two complex Gaussian variables is introduced and studied. Statistical theories are then applied to model one-point statistics about the growth of individual Fourier mode of the dark matter density field, which can be obtained by the ratio of two Fourier transformed cosmic fields. Our simulation results proved that the models based on the Gaussian approximation are impressively accurate, and our analysis revealed many interesting aspects about the growth of dark matter's density fluctuation in Fourier space. △ Less

Submitted 3 July, 2022; v1 submitted 30 September, 2021; originally announced September 2021.

Comments: 15 pages, 13 figures. Accepted by ApJ

Numerical investigation of non-Gaussianities in the phase and modulus of density Fourier modes

Authors: Jian Qin, Jun Pan, Yu Yu, Pengjie Zhang

Abstract: We numerically investigate non-Gaussianities in the late-time cosmological density field in Fourier space. We explore various statistics, including the two-point and three-point probability distribution function (PDF) of phase and modulus, and two \& three-point correlation function of of phase and modulus. We detect significant non-Gaussianity for certain configurations. We compare the simulation… ▽ More We numerically investigate non-Gaussianities in the late-time cosmological density field in Fourier space. We explore various statistics, including the two-point and three-point probability distribution function (PDF) of phase and modulus, and two \& three-point correlation function of of phase and modulus. We detect significant non-Gaussianity for certain configurations. We compare the simulation results with the theoretical expansion series of \citet{2007ApJS..170....1M}. We find that the $\mathcal{O}(V^{-1/2})$ order term alone is sufficiently accurate to describe all the measured non-Gaussianities in not only the PDFs, but also the correlations. We also numerically find that the phase-modulus cross-correlation contributes $\sim 50\%$ to the bispectrum, further verifying the accuracy of the $\mathcal{O}(V^{-1/2})$ order prediction. This work demonstrates that non-Gaussianity of the cosmic density field is simpler in Fourier space, and may facilitate the data analysis in the era of precision cosmology. △ Less

Submitted 23 September, 2021; originally announced September 2021.

Comments: 9 pages, 10 figures, comments welcome

Cross-correlation of Planck CMB lensing with DESI galaxy groups

Authors: Zeyang Sun, Ji Yao, Fuyu Dong, Xiaohu Yang, Le Zhang, Pengjie Zhang

Abstract: We measure the cross-correlation between galaxy groups constructed from DESI Legacy Imaging Survey DR8 and \emph{Planck} CMB lensing, over overlapping sky area of 16876 $\rm deg^2$. The detections are significant and consistent with the expected signal of the large-scale structure of the universe, over group samples of various redshift, mass, richness $N_{\rm g}$ and over various scale cuts. The o… ▽ More We measure the cross-correlation between galaxy groups constructed from DESI Legacy Imaging Survey DR8 and \emph{Planck} CMB lensing, over overlapping sky area of 16876 $\rm deg^2$. The detections are significant and consistent with the expected signal of the large-scale structure of the universe, over group samples of various redshift, mass, richness $N_{\rm g}$ and over various scale cuts. The overall S/N is 40 for a conservative sample with $N_{\rm g}\geq 5$, and increases to $50$ for the sample with $N_{\rm g}\geq 2$. Adopting the \emph{Planck} 2018 cosmology, we constrain the density bias of groups with $N_{\rm g}\geq 5$ as $b_{\rm g}=1.31\pm 0.10$, $2.22\pm 0.10$, $3.52\pm 0.20$ at $0.1<z\leq 0.33$, $0.33<z\leq 0.67$, $0.67<z\leq1$ respectively. The group catalog provides the estimation of group halo mass and therefore allows us to detect the dependence of bias on group mass with high significance. It also allows us to compare the measured bias with the theoretically predicted one using the estimated group mass. We find excellent agreement for the two high redshift bins. However, it is lower than the theory by $\sim 3σ$ for the lowest redshift bin. Another interesting finding is the significant impact of the thermal Sunyaev Zel'dovich (tSZ). It contaminates the galaxy group-CMB lensing cross-correlation at $\sim 30\%$ level, and must be deprojected first in CMB lensing reconstruction. △ Less

Submitted 26 January, 2022; v1 submitted 15 September, 2021; originally announced September 2021.

Comments: 13 pages, 19 figures; Accepted by MNRAS

Detection of pairwise kSZ effect with DESI galaxy clusters and Planck

Authors: Ziyang Chen, Pengjie Zhang, Xiaohu Yang, Yi Zheng

Abstract: We report a $5σ$ detection of the pairwise kinematic Sunyaev-Zel'dovich (kSZ) effect, combining galaxy clusters in DESI imaging surveys and the Planck temperature maps. The detection is facilitated by both improvements in the data and in the analysis method. For the data, we adopt the recently released galaxy group catalog (Y20: \cite{yang2020extended}) with $\sim 10^6$ robustly-identified groups,… ▽ More We report a $5σ$ detection of the pairwise kinematic Sunyaev-Zel'dovich (kSZ) effect, combining galaxy clusters in DESI imaging surveys and the Planck temperature maps. The detection is facilitated by both improvements in the data and in the analysis method. For the data, we adopt the recently released galaxy group catalog (Y20: \cite{yang2020extended}) with $\sim 10^6$ robustly-identified groups, and construct various galaxy cluster samples for the kSZ measurement. The Y20 catalogue also provides estimation of halo mass, which further improves the kSZ measurement by $\sim 10\%$. For the analysis method, we derive an optimal estimator of pairwise kSZ through the maximum likelihood analysis. It also handles potential systematic errors self-consistently. The baseline cluster sample, containing the $1.2\times 10^5$ richest galaxy clusters of typical mass ~$ 10^{14} M_{\odot}/h$ at typical redshift $0.2$-$0.5$, rules out the null hypothesis at $5σ$. When fitting with a pairwise kSZ template from simulations, the signal is detected at $4.7σ$ and the average optical depth is constrained as $\barτ_e=(1.66\pm 0.35)\times 10^{-4}$. We perform various internal checks, with different cluster selection criteria, different sky coverage and redshift range, different CMB maps, different filter sizes, different treatments of potential systematics and the covariance matrix. The kSZ effect is consistently detected with $2.5\leq $S/N$\leq 5.6$ and acceptable $χ^2_{\rm min}$, across a variety of cluster samples. The S/N is limited by both the Planck resolution and the photo-z accuracy, and therefore can be significant improved with DESI spectroscopic redshift information and with other CMB experiments. △ Less

Submitted 15 December, 2021; v1 submitted 9 September, 2021; originally announced September 2021.

Comments: 14 pages, 22 figures; Accepted to MNRAS; v2: minor revisions

Calibrating systematic errors in the distance determination with the luminosity-distance space large scale structure of dark sirens and its potential applications

Authors: Pengjie Zhang, Hai Yu

Abstract: The cosmological luminosity-distance can be measured from gravitational wave (GW) standard sirens, free of astronomical distance ladders and the associated systematics. However, it may still contain systematics arising from various astrophysical, cosmological and experimental sources. With the large amount of dark standard sirens of upcoming third generation GW experiments, such potential systemat… ▽ More The cosmological luminosity-distance can be measured from gravitational wave (GW) standard sirens, free of astronomical distance ladders and the associated systematics. However, it may still contain systematics arising from various astrophysical, cosmological and experimental sources. With the large amount of dark standard sirens of upcoming third generation GW experiments, such potential systematic bias can be diagnosed and corrected by statistical tools of the large scale structure of the universe. We estimate that, by cross-correlating the dark siren luminosity-distance space distribution and galaxy redshift space distribution, multiplicative error $m$ in the luminosity distance measurement can be constrained with $1σ$ uncertainty $σ_m\sim 0.1$. This is already able to distinguish some binary black hole origin scenarios unambiguously. Significantly better constraints and therefore more applications may be achieved by more advanced GW experiments. △ Less

Submitted 10 August, 2021; originally announced August 2021.

Comments: Accepted by MNRAS

Detection of cross-correlation between CMB Lensing and low-density points

Authors: Fuyu Dong, Pengjie Zhang, Le Zhang, Ji Yao, Zeyang Sun, Changbom Park, Xiaohu Yang

Abstract: Low Density Points (LDPs, \citet{2019ApJ...874....7D}), obtained by removing high-density regions of observed galaxies, can trace the Large-Scale Structures (LSSs) of the universe. In particular, it offers an intriguing opportunity to detect weak gravitational lensing from low-density regions. In this work, we investigate tomographic cross-correlation between Planck CMB lensing maps and LDP-traced… ▽ More Low Density Points (LDPs, \citet{2019ApJ...874....7D}), obtained by removing high-density regions of observed galaxies, can trace the Large-Scale Structures (LSSs) of the universe. In particular, it offers an intriguing opportunity to detect weak gravitational lensing from low-density regions. In this work, we investigate tomographic cross-correlation between Planck CMB lensing maps and LDP-traced LSSs, where LDPs are constructed from the DR8 data release of the DESI legacy imaging survey, with about $10^6$-$10^7$ galaxies. We find that, due to the large sky coverage (20,000 deg$^2$) and large redshift depth ($z\leq 1.2$), a significant detection ($10σ$--$30σ$) of the CMB lensing-LDP cross-correlation in all six redshift bins can be achieved, with a total significance of $\sim 53σ$ over $ \ell\le1024$. Moreover, the measurements are in good agreement with a theoretical template constructed from our numerical simulation in the WMAP 9-year $Λ$CDM cosmology. A scaling factor for the lensing amplitude $A_{\rm lens}$ is constrained to $A_{\rm lens}=1\pm0.12$ for $z<0.2$, $A_{\rm lens}=1.07\pm0.07$ for $0.2<z<0.4$ and $A_{\rm lens}=1.07\pm0.05$ for $0.4<z<0.6$, with the r-band absolute magnitude cut of $-21.5$ for LDP selection. A variety of tests have been performed to check the detection reliability, against variations in LDP samples and galaxy magnitude cuts, masks, CMB lensing maps, multipole $\ell$ cuts, sky regions, and photo-z bias. We also perform a cross-correlation measurement between CMB lensing and galaxy number density, which is consistent with the CMB lensing-LDP cross-correlation. This work therefore further convincingly demonstrates that LDP is a competitive tracer of LSS. △ Less

Submitted 20 December, 2021; v1 submitted 19 July, 2021; originally announced July 2021.

Comments: 18 pages, 11 figures; accepted by ApJ

Self-calibrating interloper bias in spectroscopic galaxy clustering surveys

Authors: Yan Gong, Haitao Miao, Pengjie Zhang, Xuelei Chen

Abstract: Contamination of interloper galaxies due to misidentified emission lines can be a big issue in the spectroscopic galaxy clustering surveys, especially in future high-precision observations. We propose a statistical method based on the cross-correlations of the observational data itself between two redshift bins to efficiently reduce this effect, and it also can derive the interloper fraction f_i i… ▽ More Contamination of interloper galaxies due to misidentified emission lines can be a big issue in the spectroscopic galaxy clustering surveys, especially in future high-precision observations. We propose a statistical method based on the cross-correlations of the observational data itself between two redshift bins to efficiently reduce this effect, and it also can derive the interloper fraction f_i in a redshift bin with a high level of accuracy. The ratio of cross and auto angular correlation functions or power spectra between redshift bins are suggested to estimate f_i, and the key equations are derived for theoretical discussion. In order to explore and prove the feasibility and effectiveness of this method, we also run simulations, generate mock data, and perform cosmological constraints considering systematics based on the observation of the China Space Station Telescope (CSST). We find that this method can effectively reduce the interloper effect, and accurately constrain the cosmological parameters for f_i<1%~10%, which is suitable for most future surveys. This method also can be applied to other kinds of galaxy clustering surveys like line intensity mapping. △ Less

Submitted 9 July, 2021; originally announced July 2021.

Comments: 6 pages, 3 figures. Accepted for publication in ApJ

Journal ref: ApJ, 919, 12 (2021)

Weak Lensing Magnification Reconstruction with the Modified Internal Linear Combination Method

Authors: Shutong Hou, Yu Yu, Pengjie Zhang

Abstract: Measuring weak lensing cosmic magnification signal is very challenging due to the overwhelming intrinsic clustering in the observed galaxy distribution. In this paper, we modify the Internal Linear Combination (ILC) method to reconstruct the lensing signal with an extra constraint to suppress the intrinsic clustering. To quantify the performance, we construct a realistic galaxy catalogue for the L… ▽ More Measuring weak lensing cosmic magnification signal is very challenging due to the overwhelming intrinsic clustering in the observed galaxy distribution. In this paper, we modify the Internal Linear Combination (ILC) method to reconstruct the lensing signal with an extra constraint to suppress the intrinsic clustering. To quantify the performance, we construct a realistic galaxy catalogue for the LSST-like photometric survey, covering $20\,000\ °^2$ with mean source redshift at $z_s\sim 1$. We find that the reconstruction performance depends on the width of the photo-z bin we choose. Due to the correlation between the lensing signal and the source galaxy distribution, the derived signal has smaller systematic bias but larger statistical uncertainty for a narrower photo-z bin. We conclude that the lensing signal reconstruction with the Modified ILC method is unbiased with a statistical uncertainty $<5\%$ for bin width $Δz^P = 0.2$. △ Less

Submitted 22 October, 2021; v1 submitted 18 June, 2021; originally announced June 2021.

Comments: 12 pages, 9 figures, match the published version in Research in Astronomy and Astrophysics

Journal ref: RAA 2021 Vol. 21 No. 10, 247 (10pp)

A linear relation between galaxy-lensing cross-correlations to test the cosmological principle model-independently

Authors: Hai Yu, Pengjie Zhang, Jiaxin Wang, Ji Yao, Fa-yin Wang

Abstract: We discover a linear relation between two sets of galaxy-lensing cross-correlations. This linear relation holds, as long as light follows the geodesic and the metric is Friedmann-Lemaître-Robertson-Walker (FLRW). Violation of the cosmological principle (and equivalently the FLRW metric) will break this linear relation. Therefore it provides a powerful test of the cosmological principle, based on d… ▽ More We discover a linear relation between two sets of galaxy-lensing cross-correlations. This linear relation holds, as long as light follows the geodesic and the metric is Friedmann-Lemaître-Robertson-Walker (FLRW). Violation of the cosmological principle (and equivalently the FLRW metric) will break this linear relation. Therefore it provides a powerful test of the cosmological principle, based on direct observables and relied on no specific cosmological models. We demonstrate that stage IV galaxy surveys and CMB-S4 experiments will be able to test this linear relation stringently and therefore test the cosmological principle robustly. △ Less

Submitted 6 June, 2021; originally announced June 2021.

Comments: 5 pages, 3 figures. Submitted

Expansion series of the pairwise velocity generating function and its implications on redshift space distortion modeling

Authors: Junde Chen, Pengjie Zhang, Yi Zheng

Abstract: The pairwise velocity generating function $G$ has deep connection with both the pairwise velocity probability distribution function and modeling of redshift space distortion (RSD). Its implementation into RSD modeling is often faciliated by expansion into series of pairwise velocity moments $\langle v_{12}^n\rangle$. Motivated by the logrithmic transformation of the cosmic density field, we invest… ▽ More The pairwise velocity generating function $G$ has deep connection with both the pairwise velocity probability distribution function and modeling of redshift space distortion (RSD). Its implementation into RSD modeling is often faciliated by expansion into series of pairwise velocity moments $\langle v_{12}^n\rangle$. Motivated by the logrithmic transformation of the cosmic density field, we investigate an alternative expansion into series of pairwise velocity cumulants $\langle v_{12}^n\rangle_c$ . We numerically evaluate the convergence rate of the two expansions, with three $3072^3$ particle simulations of the CosmicGrowth N-body simulation series. (1) We find that the cumulant expansion performs significantly better, for all the halo samples and redshifts investigated. (2) For modeling RSD at $k_{\|}<0.1 h$ Mpc$^{-1}$, including only the $n=1,2$ cumulants is sufficient. (3) But for modeling RSD at $k_\parallel=0.2 h$ Mpc$^{-1}$, we need and only need the $n=1,2,3,4$ cumulants. These results provide specific requirements on RSD modeling in terms of $m$-th order statistics of the large scale strucure. △ Less

Submitted 23 March, 2021; v1 submitted 22 March, 2021; originally announced March 2021.

Comments: 19 pages, 11 figures

The design of the Ali CMB Polarization Telescope receiver

Authors: Maria Salatino, Jason E. Austermann, Keith L. Thompson, Peter A. R. Ade, Xiran Bai, James A. Beall, Dan T. Becker, Yifu Cai, Zhi Chang, Ding Chen, Pisin Chen, Jake Connors, Jacques Delabrouille, Bradley Dober, Shannon M. Duff, Guanhua Gao, Shamik Ghosh, Richard C. Givhan, Gene C. Hilton, Bin Hu, Johannes Hubmayr, Ethan D. Karpel, Chao-Lin Kuo, Hong Li, Mingzhe Li , et al. (50 additional authors not shown)

Abstract: Ali CMB Polarization Telescope (AliCPT-1) is the first CMB degree-scale polarimeter to be deployed on the Tibetan plateau at 5,250m above sea level. AliCPT-1 is a 90/150 GHz 72 cm aperture, two-lens refracting telescope cooled down to 4 K. Alumina lenses, 800mm in diameter, image the CMB in a 33.4° field of view on a 636mm wide focal plane. The modularized focal plane consists of dichroic polariza… ▽ More Ali CMB Polarization Telescope (AliCPT-1) is the first CMB degree-scale polarimeter to be deployed on the Tibetan plateau at 5,250m above sea level. AliCPT-1 is a 90/150 GHz 72 cm aperture, two-lens refracting telescope cooled down to 4 K. Alumina lenses, 800mm in diameter, image the CMB in a 33.4° field of view on a 636mm wide focal plane. The modularized focal plane consists of dichroic polarization-sensitive Transition-Edge Sensors (TESes). Each module includes 1,704 optically active TESes fabricated on a 150mm diameter silicon wafer. Each TES array is read out with a microwave multiplexing readout system capable of a multiplexing factor up to 2,048. Such a large multiplexing factor has allowed the practical deployment of tens of thousands of detectors, enabling the design of a receiver that can operate up to 19 TES arrays for a total of 32,376 TESes. AliCPT-1 leverages the technological advancements in the detector design from multiple generations of previously successful feedhorn-coupled polarimeters, and in the instrument design from BICEP-3, but applied on a larger scale. The cryostat receiver is currently under integration and testing. During the first deployment year, the focal plane will be populated with up to 4 TES arrays. Further TES arrays will be deployed in the following years, fully populating the focal plane with 19 arrays on the fourth deployment year. Here we present the AliCPT-1 receiver design, and how the design has been optimized to meet the experimental requirements. △ Less

Submitted 23 January, 2021; originally announced January 2021.

Comments: Proc. SPIE, 11453, 114532A (2020)

Journal ref: Proceedings of SPIE, 'Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy X', Volume 11453, 114532A (2020)

Does Concentration Drive the Scatter in the Stellar-to-Halo Mass Relation of Galaxy Clusters?

Authors: Ying Zu, Huanyuan Shan, Jun Zhang, Sukhdeep Singh, Zhiwei Shao, Xiaokai Chen, Ji Yao, Jesse B. Golden-Marx, Weiguang Cui, Eric Jullo, Jean-Paul Kneib, Pengjie Zhang, Xiaohu Yang

Abstract: Concentration is one of the key dark matter halo properties that could drive the scatter in the stellar-to-halo mass relation of massive clusters. We derive robust photometric stellar masses for a sample of brightest central galaxies (BCGs) in SDSS redMaPPer clusters at $0.17<z<0.3$, and split the clusters into two equal-halo mass subsamples by their BCG stellar mass $M_*$. The weak lensing profil… ▽ More Concentration is one of the key dark matter halo properties that could drive the scatter in the stellar-to-halo mass relation of massive clusters. We derive robust photometric stellar masses for a sample of brightest central galaxies (BCGs) in SDSS redMaPPer clusters at $0.17<z<0.3$, and split the clusters into two equal-halo mass subsamples by their BCG stellar mass $M_*$. The weak lensing profiles $ΔΣ$ of the two cluster subsamples exhibit different slopes on scales below 1 M$pc/h$. To interpret such discrepancy, we perform a comprehensive Bayesian modelling of the two $ΔΣ$ profiles by including different levels of miscentring effects between the two subsamples as informed by X-ray observations. We find that the two subsamples have the same average halo mass of $1.74 \times 10^{14} M_{\odot}/h$, but the concentration of the low-$M_*$ clusters is $5.87_{-0.60}^{+0.77}$, ${\sim}1.5σ$ smaller than that of their high-$M_*$ counterparts~($6.95_{-0.66}^{+0.78}$). Furthermore, both cluster weak lensing and cluster-galaxy cross-correlations indicate that the large-scale bias of the low-$M_*$, low-concentration clusters are ${\sim}10\%$ higher than that of the high-$M_*$, high-concentration systems, hence possible evidence of the cluster assembly bias effect. Our results reveal a remarkable physical connection between the stellar mass within 20{-}30 k$pc/h$, the dark matter mass within ${\sim}$ 200 k$pc/h$, and the cosmic overdensity on scales above 10 M$pc/h$, enabling a key observational test of theories of co-evolution between massive clusters and their central galaxies. △ Less

Submitted 29 June, 2021; v1 submitted 15 December, 2020; originally announced December 2020.

Comments: 12 pages, 6 figures, matched to the published version in MNRAS

Journal ref: Monthly Notices of the Royal Astronomical Society, 2021, Volume 505, Issue 4, pp. 5117-5128

Strong lensing as a giant telescope to localize the host galaxy of gravitational wave event

Authors: Hai Yu, Pengjie Zhang, Fa-Yin Wang

Abstract: Standard siren cosmology of gravitational wave (GW) merger events relies on the identification of host galaxies and their redshifts. But this can be highly challenging due to numerous candidates of galaxies in the GW localization area. We point out that the number of candidates can be reduced by orders of magnitude for strongly lensed GW events, due to extra observational constraints. For the next… ▽ More Standard siren cosmology of gravitational wave (GW) merger events relies on the identification of host galaxies and their redshifts. But this can be highly challenging due to numerous candidates of galaxies in the GW localization area. We point out that the number of candidates can be reduced by orders of magnitude for strongly lensed GW events, due to extra observational constraints. For the next-generation GW detectors like Einstein Telescope (ET), we estimate that this number is usually significantly less than one, as long as the GW localization uncertainty is better than $\sim 10\, \rm deg^2$. This implies that the unique identification of the host galaxy of lensed GW event detected by ET and Cosmic Explorer (CE) is possible. This provides us a promising opportunity to measure the redshift of the GW event and facilitate the standard siren cosmology. We also discuss its potential applications in understanding the evolution process and environment of the GW event. △ Less

Submitted 4 July, 2020; v1 submitted 1 July, 2020; originally announced July 2020.

Comments: 6 pages, 6 figures, submitted to MNRAS on March 13, 2020, accepted on July 1, 2020

Measuring the integrated Sachs-Wolfe effect from the low-density regions of the universe

Authors: Fuyu Dong, Yu Yu, Jun Zhang, Xiaohu Yang, Pengjie Zhang

Abstract: The integrated Sachs-Wolfe (ISW) effect is caused by the decay of cosmological gravitational potential, and is therefore a unique probe of dark energy. However, its robust detection is still problematic. Various tensions between different data sets, different large scale structure (LSS) tracers, and between data and the $Λ$CDM theory prediction, exist. We propose a novel method of ISW measurement… ▽ More The integrated Sachs-Wolfe (ISW) effect is caused by the decay of cosmological gravitational potential, and is therefore a unique probe of dark energy. However, its robust detection is still problematic. Various tensions between different data sets, different large scale structure (LSS) tracers, and between data and the $Λ$CDM theory prediction, exist. We propose a novel method of ISW measurement by cross correlating CMB and the LSS traced by "low-density-position" (LDP, \citet{2019ApJ...874....7D}). It isolates the ISW effect generated by low-density regions of the universe, but insensitive to selection effects associated with voids. We apply it to the DR8 galaxy catalogue of the DESI Legacy imaging surveys, and obtain the LDPs at $z\leq 0.6$ over $\sim$ 20000 $deg^2$ sky coverage. We then cross correlate with the Planck temperature map, and detect the ISW effect at $3.2σ$. We further compare the measurement with numerical simulations of the concordance $Λ$CDM cosmology, and find the ISW amplitude parameter $A_{ISW}=1.14\pm0.38$ when we adopt a LDP definition radius $R_s=3^{'}$, fully consistent with the prediction of the standard $Λ$CDM cosmology ($A_{ISW}=1$). This agreement with $Λ$CDM cosmology holds for all the galaxy samples and $R_s$ that we have investigated. Furthermore, the S/N is comparable to that of galaxy ISW measurement. These results demonstrate the LDP method as a competitive alternative to existing ISW measurement methods, and provide independent checks to existing tensions. △ Less

Submitted 25 June, 2020; originally announced June 2020.

Comments: 16 pages, 14 figures

The copula of the cosmological matter density field is non-Gaussian

Authors: Jian Qin, Yu Yu, Pengjie Zhang

Abstract: Non-Gaussianity of the cosmological matter density field can be largely reduced by a local Gaussianization transformation (and its approximations such as the logrithmic transformation). Such behavior can be recasted as the Gaussian copula hypothesis, and has been verified to very high accuracy at two-point level. On the other hand, statistically significant non-Gaussianities in the Gaussianized fi… ▽ More Non-Gaussianity of the cosmological matter density field can be largely reduced by a local Gaussianization transformation (and its approximations such as the logrithmic transformation). Such behavior can be recasted as the Gaussian copula hypothesis, and has been verified to very high accuracy at two-point level. On the other hand, statistically significant non-Gaussianities in the Gaussianized field have been detected in simulations. We point out that, this apparent inconsistency is caused by the very limited degrees of freedom in the copula function, which make it misleading as a diagnosis of residual non-Gaussianity in the Gaussianized field. Using the copula density, we highlight the departure from Gaussianity. We further quantify its impact in the predicted n-point correlation functions. We explore a remedy of the Gaussian copula hypothesis, which alleviates but not completely solves the above problems. △ Less

Submitted 11 June, 2020; originally announced June 2020.

Comments: 8 pages, 5 figures, ApJ in press

Unveiling the Intrinsic Alignment of Galaxies with Self-Calibration and DECaLS DR3 data

Authors: Ji Yao, Huanyuan Shan, Pengjie Zhang, Jean-Paul Kneib, Eric Jullo

Abstract: Galaxy intrinsic alignment (IA) is both a source of systematic contamination to cosmic shear measurement and its cosmological applications, and a source of valuable information on the large scale structure of the universe and galaxy formation. The self-calibration (SC) method \citep{SC2008} was designed to separate IA from cosmic shear, free of IA modeling. It was first successfully applied to the… ▽ More Galaxy intrinsic alignment (IA) is both a source of systematic contamination to cosmic shear measurement and its cosmological applications, and a source of valuable information on the large scale structure of the universe and galaxy formation. The self-calibration (SC) method \citep{SC2008} was designed to separate IA from cosmic shear, free of IA modeling. It was first successfully applied to the KiDS450 and KV450 data \citep{Yao2019}. We apply the SC method to the DECaLS DR3 shear + photo-z catalog and significantly improve the IA detection to $\sim 14σ$. We find a strong dependence of IA on galaxy color, with strong IA signal ($\sim17.6σ$) for red galaxies, while the IA signal for blue galaxies is consistent with zero. The detected IA for red galaxies are in reasonable agreement with the non-linear tidal alignment model and the inferred IA amplitude increases with redshift. We address the systematics in the SC method carefully and performed several sanity checks. We discuss various caveats and possible improvements in the measurement, theory and parameter fitting that will be addressed in future works. △ Less

Submitted 8 November, 2020; v1 submitted 22 February, 2020; originally announced February 2020.

Comments: match version accepted by ApJ

Neutrino effects on the morphology of cosmic large-scale structure

Authors: Yu Liu, Yu Yu, Hao-Ran Yu, Pengjie Zhang

Abstract: In this work, we propose a powerful probe of neutrino effects on the large-scale structure (LSS) of the Universe, i.e., Minkowski functionals (MFs). The morphology of LSS can be fully described by four MFs. This tool, with strong statistical power, is robust to various systematics and can comprehensively probe all orders of N-point statistics. By using a pair of high-resolution N-body simulations,… ▽ More In this work, we propose a powerful probe of neutrino effects on the large-scale structure (LSS) of the Universe, i.e., Minkowski functionals (MFs). The morphology of LSS can be fully described by four MFs. This tool, with strong statistical power, is robust to various systematics and can comprehensively probe all orders of N-point statistics. By using a pair of high-resolution N-body simulations, for the first time, we comprehensively studied the subtle neutrino effects on the morphology of LSS. For an ideal LSS survey of volume $\sim1.73$ Gpc$^3$/$h^3$, neutrino signals are mainly detected from void regions with a significant level up to $\thicksim 10σ$ and $\thicksim 300σ$ for CDM and total matter density fields, respectively. This demonstrates its enormous potential for much improving the neutrino mass constraint in the data analysis of up-coming ambitious LSS surveys. △ Less

Submitted 20 March, 2020; v1 submitted 20 February, 2020; originally announced February 2020.

Comments: 8 pages, 2 figures, published in PRD

Journal ref: Phys.Rev.D 101,063515 (2020)

First detection of the GI-type of intrinsic alignments of galaxies using the self-calibration method in a photometric galaxy survey

Authors: Eske M. Pedersen, Ji Yao, Mustapha Ishak, Pengjie Zhang

Abstract: Weak gravitational lensing is one of the most promising cosmological probes to constrain dark matter, dark energy, and the nature of gravity at cosmic scales. Intrinsic alignments (IAs) of galaxies have been recognized as one of the most serious systematic effects facing gravitational lensing. Such alignments must be isolated and removed to obtain a pure lensing signal. Furthermore, the alignments… ▽ More Weak gravitational lensing is one of the most promising cosmological probes to constrain dark matter, dark energy, and the nature of gravity at cosmic scales. Intrinsic alignments (IAs) of galaxies have been recognized as one of the most serious systematic effects facing gravitational lensing. Such alignments must be isolated and removed to obtain a pure lensing signal. Furthermore, the alignments are related to the processes of galaxy formation, so their extracted signal can help in understanding such formation processes and improving their theoretical modeling. We report in this Letter the first detection of the gravitational shear--intrinsic shape (GI) correlation and the intrinsic shape--galaxy density (Ig) correlation using the self-calibration method in a photometric redshift survey. These direct measurements are made from the KiDS-450 photometric galaxy survey with a significance of 3.65$σ$ in the third bin for the Ig correlation, and 3.51$σ$ for the GI cross-correlation between the third and fourth bins. The self-calibration method uses the information available from photometric surveys without needing to specify an IA model and will play an important role in validating IA models and IA mitigation in future surveys such as the Rubin Observatory Legacy Survey of Space and Time, Euclid, and WFIRST. △ Less

Submitted 22 August, 2020; v1 submitted 4 November, 2019; originally announced November 2019.

Comments: 8 pages, 2 figures

Journal ref: ApJL 899 L5 (2020)

Separating the Intrinsic Alignment Signal and the Lensing Signal using Self-Calibration in Photo-z Surveys with KiDS450 and KV450 Data

Authors: Ji Yao, Eske M. Pedersen, Mustapha Ishak, Pengjie Zhang, Anish Agashe, Haojie Xu, Huanyuan Shan

Abstract: To reach the full potential for the next generation of weak lensing surveys, it is necessary to mitigate the contamination of intrinsic alignments (IA) of galaxies in the observed cosmic shear signal. The self calibration (SC) of intrinsic alignments provides an independent method to measure the IA signal from the survey data and the photometric redshift information. It operates differently from t… ▽ More To reach the full potential for the next generation of weak lensing surveys, it is necessary to mitigate the contamination of intrinsic alignments (IA) of galaxies in the observed cosmic shear signal. The self calibration (SC) of intrinsic alignments provides an independent method to measure the IA signal from the survey data and the photometric redshift information. It operates differently from the marginalization method based on IA modeling. In this work, we present the first application of SC to the KiDS450 data and the KV450 data, to split directly the intrinsic shape - galaxy density (Ig) correlation signal and the gravitational shear - galaxy density (Gg) correlation signal, using the information from photometric redshift (photo-z). We achieved a clear separation of the two signals and performed several validation tests. Our measured signals are found to be in general agreement with the KiDS450 cosmic shear best-fit cosmology, for both lensing and IA measurements. For KV450, we use partial (high-z) data, and our lensing measurements are also in good agreement with KV450 cosmic shear best-fit, however, our IA signal suggests a larger IA amplitude. We discussed the impact of photo-z quality on IA detection and several other potential systematic biases. Finally, we discuss the potential application of the information extracted for both the lensing signal and the IA signal in future surveys. △ Less

Submitted 8 May, 2020; v1 submitted 4 November, 2019; originally announced November 2019.

Comments: revision, 15 figures, accepted by MNRAS

Forecast for FAST: from Galaxies Survey to Intensity Mapping

Authors: Wenkai Hu, Xin Wang, Fengquan Wu, Yougang Wang, Pengjie Zhang, Xuelei Chen

Abstract: The Five-Hundred-Meter Aperture Spherical Radio Telescope(FAST) is the largest single-dish radio telescope in the world. In this paper, we make forecast on the FAST HI large scale structure survey by mock observations. We consider a drift scan survey with the L-band 19 beam receiver, which may be commensal with the pulsar search and Galactic HI survey. We also consider surveys at lower frequency,… ▽ More The Five-Hundred-Meter Aperture Spherical Radio Telescope(FAST) is the largest single-dish radio telescope in the world. In this paper, we make forecast on the FAST HI large scale structure survey by mock observations. We consider a drift scan survey with the L-band 19 beam receiver, which may be commensal with the pulsar search and Galactic HI survey. We also consider surveys at lower frequency, either using the current single feed wide band receiver, or a future multi-beam phased array feed (PAF) in the UHF band. We estimate the number density of detected HI galaxies and the measurement error in positions, the precision of the surveys are evaluated using both Fisher matrix and simulated observations. The measurement error in the HI galaxy power spectrum is estimated, and we find that the error is relatively large even at moderate redshifts, as the number of positively detected galaxies drops drastically with increasing redshift. However, good cosmological measurement could be obtained with the intensity mapping technique where the large scale HI distribution is measured without resolving individual galaxies. The figure of merit (FoM) for the dark energy equation of state with different observation times are estimated, we find that with the existing L-band multi-beam receiver, a good measurement of low redshift large scale structure can be obtained, which complements the existing optical surveys. With a PAF in the UHF band, the constraint can be much stronger, reaching the level of a dark energy task force (DETF) stage IV experiment. △ Less

Submitted 27 March, 2020; v1 submitted 24 September, 2019; originally announced September 2019.

Comments: 17 pages, 18 figures, fixed problems in references, version accepted by MNRAS

Reconstructing simulated CMB polarization power spectra with the Analytical Blind Separation method

Authors: Larissa Santos, Jian Yao, Le Zhang, Shamik Ghosh, Pengjie Zhang, Wen Zhao, Thyrso Villela, Jiming Chen, Jacques Delabrouille

Abstract: Multi-frequency observations are needed to separate the CMB from foregrounds and accurately extract cosmological information from the data. The Analytical Blind Separation (ABS) method is dedicated to extracting the CMB power spectrum from multi-frequency observations in the presence of contamination from astrophysical foreground emission and instrumental noise. In this study, we apply the ABS met… ▽ More Multi-frequency observations are needed to separate the CMB from foregrounds and accurately extract cosmological information from the data. The Analytical Blind Separation (ABS) method is dedicated to extracting the CMB power spectrum from multi-frequency observations in the presence of contamination from astrophysical foreground emission and instrumental noise. In this study, we apply the ABS method to simulated sky maps as could be observed with a future space-borne survey, in order to test the method's capability for determining the CMB polarization $E$- and $B$-mode power spectra. We present the ABS method performance on simulations for both a full-sky analysis and for an analysis concentrating on sky regions less impacted by Galactic foreground emission. We discuss the origin and minimization of biases in the estimated CMB polarization angular power spectra. We find that the ABS method performs quite well for the analysis of full-sky observations at intermediate and small angular scales, in spite of strong foreground contamination. On the largest scales, extra work is still required to reduce biases of various origins and the impact of confusion between CMB $E$ and $B$ polarization for partial-sky analyses. △ Less

Submitted 18 March, 2021; v1 submitted 21 August, 2019; originally announced August 2019.

Comments: Accepted to A&A

Accurate redshift determination of standard sirens by the luminosity distance space-redshift space large scale structure cross correlation

Authors: Pengjie Zhang

Abstract: We point out a new possibility to determine the average redshift distribution of a large sample of gravitational wave standard sirens, without spectroscopic follow-ups. It is based on the cross correlation between the luminosity-distance space large scale structure (LSS) traced by standard sirens, and the redshift space LSS traced by galaxies in preexisting electromagnetic wave observations. We co… ▽ More We point out a new possibility to determine the average redshift distribution of a large sample of gravitational wave standard sirens, without spectroscopic follow-ups. It is based on the cross correlation between the luminosity-distance space large scale structure (LSS) traced by standard sirens, and the redshift space LSS traced by galaxies in preexisting electromagnetic wave observations. We construct an unbiased and model independent estimator $E_z$ to realize this possibility. We demonstrate with BBO and Euclid that, $0.1\%$ accuracy in redshift determination can be achieved. This method can significantly alleviate the need of spectroscopic follow-up of standard sirens, and enhance their cosmological applications. △ Less

Submitted 17 November, 2018; originally announced November 2018.

Comments: 5 pages, 3 figures. To be submitted

The large scale structure in the 3D luminosity-distance space and its cosmological applications

Authors: Pengjie Zhang

Abstract: Future gravitational wave (GW) observations are capable of detecting millions of compact star binary mergers in extragalactic galaxies, with $1\%$ luminosity-distance ($D_L$) measurement accuracy and better than arcminute positioning accuracy. This will open a new window of the large scale structure (LSS) of the universe, in the 3D {\bf luminosity-distance space (LDS)}, instead of the 3D redshift… ▽ More Future gravitational wave (GW) observations are capable of detecting millions of compact star binary mergers in extragalactic galaxies, with $1\%$ luminosity-distance ($D_L$) measurement accuracy and better than arcminute positioning accuracy. This will open a new window of the large scale structure (LSS) of the universe, in the 3D {\bf luminosity-distance space (LDS)}, instead of the 3D redshift space of galaxy spectroscopic surveys. The baryon acoustic oscillation and the AP test encoded in the LDS LSS constrain the $D_L$-$D^{\rm co}_A$ (comoving angular diameter distance) relation and therefore the expansion history of the universe. Peculiar velocity induces the LDS distortion, analogous to the redshift space distortion, and allows for a new structure growth measure $f_Lσ_8$. When the distance duality is enforced ($1+z=D_L/D^{\rm co}_A$), the LDS LSS by itself determines the redshift to $\sim 1\%$ level accuracy, and alleviates the need of spectroscopic follow-up of GW events.But a more valuable application is to test the distance duality to $1\%$ level accuracy, in combination with conventional BAO and supernovae measurements. This will put stringent constraints on modified gravity models in which the gravitational wave $D^{\rm GW}_L$ deviates from the electromagnetic wave $D^{EM}_L$. All these applications require no spectroscopic follow-ups. △ Less

Submitted 28 October, 2018; originally announced October 2018.

Comments: 5 pages, to be submitted to PRL

A possible explanation of vanishing halo velocity bias

Authors: Pengjie Zhang

Abstract: Recently Chen et al. (2018, ApJ, 861, 58) accurately determined the volume weighted halo velocity bias in simulations, and found that the deviation of velocity bias from unity is much weaker than the peak model prediction. Here we present a possible explanation of this vanishing velocity bias. The starting point is that, halos are peaks in the low redshift {\it non-Gaussian} density field with smo… ▽ More Recently Chen et al. (2018, ApJ, 861, 58) accurately determined the volume weighted halo velocity bias in simulations, and found that the deviation of velocity bias from unity is much weaker than the peak model prediction. Here we present a possible explanation of this vanishing velocity bias. The starting point is that, halos are peaks in the low redshift {\it non-Gaussian} density field with smoothing scale $R_Δ$ (virial radius), instead of peaks in the high redshift initial {\it Gaussian} density field with a factor of $\mathcal{O}(Δ^{1/3})$ larger smoothing scale. Based on the approximation that the density field can be Gaussianized by a local and monotonic transformation, we extend the peak model to the non-Gaussian density field and derive the analytical expression of velocity dispersion and velocity power spectrum of these halos. The predicted deviation of velocity bias from unity is indeed much weaker than the previous prediction, and the agreement with the simulation results is significantly improved. △ Less

Submitted 8 January, 2019; v1 submitted 27 August, 2018; originally announced August 2018.

Comments: 4 pages. ApJ, 869, 74

Journal ref: The Astrophysical Journal, Volume 869, Issue 1, article id. 74, 4 pp. (2018)

Testing the ABS method with the simulated Planck temperature maps

Authors: Jian Yao, Le Zhang, Yuxi Zhao, Pengjie Zhang, Larissa Santos, Jun Zhang

Abstract: In this study, we apply the Analytical method of Blind Separation (ABS) of the cosmic microwave background (CMB) from foregrounds to estimate the CMB temperature power spectrum from multi-frequency microwave maps. We test the robustness of the ABS estimator and assess the accuracy of the power spectrum recovery by using realistic simulations based on the seven-frequency Planck data, including vari… ▽ More In this study, we apply the Analytical method of Blind Separation (ABS) of the cosmic microwave background (CMB) from foregrounds to estimate the CMB temperature power spectrum from multi-frequency microwave maps. We test the robustness of the ABS estimator and assess the accuracy of the power spectrum recovery by using realistic simulations based on the seven-frequency Planck data, including various frequency-dependent and spatially-varying foreground components (synchrotron, free-free, thermal dust and anomalous microwave emission), as well as an uncorrelated Gaussian-distributed instrumental noise. Considering no prior information about the foregrounds, the ABS estimator can analytically recover the CMB power spectrum over almost all scales with less than $0.5\%$ error for maps where the Galactic plane region ($|b|<10^{\circ}$) is masked out. To further test the flexibility and effectiveness of the ABS approach in a variety of situations, we apply the ABS to the simulated Planck maps in three cases: (1) without any mask, (2) imposing a two-times-stronger synchrotron emission and (3) including only the Galactic plane region ($|b|<10^{\circ}$) in the analysis. In such extreme cases, the ABS approach can still provide an unbiased estimate of band powers at the level of 1 $μ\rm{K}^2$ on average over all $\ell$ range, and the recovered powers are consistent with the input values within 1-$σ$ for most $\ell$ bins. △ Less

Submitted 7 November, 2018; v1 submitted 18 July, 2018; originally announced July 2018.

Comments: 12 pages, 11 figures, revised version, accepted to APJS

Journal ref: The Astrophysical Journal Supplement Series, 239:36 (12pp), 2018 December

Weak lensing power spectrum reconstruction by counting galaxies.-- II: Improving the ABS method with the shift parameter

Authors: Pengjie Zhang, Xinjuan Yang, Jun Zhang, Yu Yu

Abstract: In paper I of this series (Yang et al. 2017, ApJ), we proposed an analytical method of blind separation ({\bf ABS}) to extract the cosmic magnification signal in galaxy number distribution and reconstruct the weak lensing power spectrum. Here we report a new version of the ABS method, with significantly improved performance. This version is characterized by a shift parameter $\mathcal{S}$, with th… ▽ More In paper I of this series (Yang et al. 2017, ApJ), we proposed an analytical method of blind separation ({\bf ABS}) to extract the cosmic magnification signal in galaxy number distribution and reconstruct the weak lensing power spectrum. Here we report a new version of the ABS method, with significantly improved performance. This version is characterized by a shift parameter $\mathcal{S}$, with the special case of $\mathcal{S}=0$ corresponding to the original ABS method. We have tested this new version, compared to the previous one, and confirmed its supreme performance in all investigated situations. Therefore it supersedes the previous version. The proof of concept studies presented in this paper demonstrate that it may enable surveys such as LSST and SKA to reconstruct the lensing power spectrum at $z\simeq 1$ with $1\%$ accuracy. We will test with more realistic simulations to verify its applicability in real data. △ Less

Submitted 1 July, 2018; originally announced July 2018.

Comments: 4 pages, 5 figures. Accepted to ApJ

Journal ref: The Astrophysical Journal, Volume 864, Issue 1, article id. 10, 4 pp. (2018)

Verifications of scaling relations useful for the intrinsic alignment self-calibration

Authors: Xian-guang Meng, Yu Yu, Pengjie Zhang, Yipeng Jing

Abstract: The galaxy intrinsic alignment (IA) is a major challenge of weak lensing cosmology. To alleviate this problem, Zhang (2010, MNRAS, 406, L95) proposed a self-calibration method, independent of IA modeling. This proposal relies on several scaling relations between two-point clustering of IA and matter/galaxy fields, which were previously only tested with analytical IA models. In this paper, these re… ▽ More The galaxy intrinsic alignment (IA) is a major challenge of weak lensing cosmology. To alleviate this problem, Zhang (2010, MNRAS, 406, L95) proposed a self-calibration method, independent of IA modeling. This proposal relies on several scaling relations between two-point clustering of IA and matter/galaxy fields, which were previously only tested with analytical IA models. In this paper, these relations are tested comprehensively with an $N$-body simulation of $3072^3$ simulation particles and boxsize 600 $h^{-1} \, \mathrm{Mpc}$. They are verified at the accuracy level of $\mathcal{O}(1)\%$ over angular scales and source redshifts of interest. We further confirm that these scaling relations are generic, insensitive to halo mass, weighting in defining halo ellipticities, photo-$z$ error, and misalignment between galaxy ellipticities and halo ellipticities. We also present and verify three new scaling relations on the B-mode IA. These results consolidate and complete the theory side of the proposed self-calibration technique. △ Less

Submitted 26 August, 2018; v1 submitted 9 May, 2018; originally announced May 2018.

Comments: 6 pages, 7 figures, published in ApJ

Journal ref: ApJ(2018),864,1