A5043022239- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- CCD and CMOS Imaging Sensors
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Real-time simulation and control systems
- History and Developments in Astronomy
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Calibration and Measurement Techniques
- Infrared Target Detection Methodologies
- Advanced Image Processing Techniques
- Alkaline Phosphatase Research Studies
- Optical measurement and interference techniques
- Plant Water Relations and Carbon Dynamics
- Optical Systems and Laser Technology
- Advanced Vision and Imaging
- Microbial Community Ecology and Physiology
- Dark Matter and Cosmic Phenomena
Purple Mountain Observatory
2018-2024
University of Chinese Academy of Sciences
2018
University of Science and Technology of China
2018
Yale University
2018
Reconstructing the dark matter density, velocity, and tidal (MTV) fields from galaxy surveys is essential for advancing our understanding of large-scale structure Universe. In this work, we present a machine learning-based framework using UNet convolutional neural network to reconstruct MTV mock samples DESI bright survey within redshift range $0.1 < z 0.4$. Our approach accounts realistic observational effects, including geometric selection, flux-limited data, space distortion (RSD) thereby...
The issue of over-predicting the galaxy-galaxy lensing (GGL) signal using conventional galaxy-halo connection models has become well-known as ``Lensing is Low'' problem, which been extensively investigated Baryon Oscillation Spectroscopic Survey (BOSS) galaxy samples. This also tightly related to so-called $S_8$ tension. By applying our Photometric objects Around Cosmic webs (PAC) method BOSS survey and DESI deep photometric survey, we obtained hundreds cross-correlation measurements...
We examine the quenched fraction of central and satellite galaxies as a function galaxy stellar mass, halo matter density their large scale environment. Matter densities are inferred from our ELUCID simulation, constrained simulation local Universe sampled by SDSS, while masses central/satellite classification taken group catalog Yang et al. The for total population increases systematically with three quantities. find that `environmental quenching efficiency', which quantifies is independent...
Context . Weak gravitational lensing is one of the most important probes nature dark matter and energy. In order to extract cosmological information from next-generation weak surveys (e.g., Euclid , Roman LSST, CSST) as much possible, accurate measurements shear are required. Aims There existing algorithms measure on imaging data, which have been successfully applied in previous surveys. meantime, machine learning (ML) has widely recognized various astrophysics applications modeling...
In this paper, we set out to construct a 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 MGRSs is generated using dark matter subhalos extracted from high-resolution Jiutian $N$-body simulation standard $\Lambda$CDM cosmogony with $\Omega_m=0.3111$, $\Omega_{\Lambda}=0.6889$, $\sigma_8=0.8102$. The has boxsize $1~h^{-1} {\rm Gpc}$, consists...
ABSTRACT We investigate emission line galaxies across cosmic time by combining the modified L-Galaxies semi-analytical galaxy formation model with JiuTian cosmological simulation. improve tidal disruption of satellite in to address dependence problem. utilize public code cloudy compute ratios for a grid H ii region models. The models assume same initial mass function as that used generate spectral energy distribution galaxies, ensuring coherent treatment modelling full spectrum. By...
ABSTRACT Void size function (VSF) contains the information of cosmic large-scale structure (LSS), and can be used to derive properties dark energy matter. We predict VSFs measured from spectroscopic galaxy survey operated by China’s Space Survey Telescope (CSST), study strength cosmological constraint. employ a high-resolution Jiutian simulation get CSST mock samples based on an improved semi-analytical model. identify voids this catalogue using watershed algorithm without assuming spherical...
Abstract The intrinsic alignment of galaxies is an important systematic effect in weak-lensing surveys, which can affect the derived cosmological parameters. One direct way to distinguish different models and quantify their effects on measurement produce mock surveys. In this work, we use full-sky ray-tracing technique images from ELUCID N -body simulation run with WMAP9 cosmology. our model, assume that shape central elliptical galaxy follows dark matter halo, spiral halo spin. Using...
Aims. With the next generation of large surveys coming to stage observational cosmology soon, it is important explore their potential synergies and maximise scientific outcomes. In this study, we aim investigate complementarity two upcoming space missions Euclid China Space Station Telescope (CSST), focusing on weak lensing (WL) cosmology. particular, analyse photometric redshifts (photo-zs) galaxy blending effects. For Euclid, WL measurements suffer from chromatic PSF this, CSST can provide...
ABSTRACT We predict the dwarf galaxy detection limits for upcoming Chinese Space Station Telescope (CSST) survey that will cover 17 500 ${\rm \, deg}^{2}$ of sky with a wide field view 1.1 deg2. The point-source depth reaches 26.3 mag in g band and 25.9 i band. Constructing mock data based on designed photometric bands, we estimate recovery rate artificial galaxies from catalogues. these is strongly dependent their distance, magnitude, size, agreement searches current surveys. expect CSST to...
In a recent study, using the distribution of galaxies in north galactic pole SDSS DR7 region enclosed 500$\mpch$ box, we carried out our ELUCID simulation (Wang et al. 2016, III). Here {\it light} dark matter halos and subhalos reconstructed with observations novel neighborhood} abundance matching method. Before make use thus established galaxy-subhalo connections to evaluate galaxy formation models, set explore reliability such link. For this purpose, focus on following few aspects...
Abstract Strong gravitational lensing is a powerful tool for investigating dark matter and energy properties. With the advent of large-scale sky surveys, we can discover strong-lensing systems on an unprecedented scale, which requires efficient tools to extract them from billions astronomical objects. The existing mainstream lens-finding are based machine-learning algorithms applied cutout-centered galaxies. However, according design survey strategy optical surveys by China Space Station...
ABSTRACT The precise estimation of the statistical errors and accurate removal systematical are two major challenges for stage IV cosmic shear surveys. We explore their impact China Space Station Telescope (CSST) with survey area ${\sim} 17\,500\deg ^2$ up to redshift ∼4. consider error contributed from Gaussian covariance, connected non-Gaussian super-sample covariance. find covariances, which is dominated by can largely reduce signal-to-noise ratio two-point statistics CSST, leading an...
Abstract The galaxy intrinsic alignment (IA) is a dominant source of systematics in weak lensing (WL) studies. In this paper, by employing large simulations with semianalytical formation, we investigate the IA effects on WL peak statistics. Different simulated samples different redshift distributions are constructed, where both shear and signals included. Convergence reconstruction statistics then performed for these samples. Our results show that abundances mainly consist two aspects. One...
Gravitational waves (GWs) may be magnified or de-magnified due to lensing. This phenomenon will bias the distance estimation based on matched filtering technique. Via multi-sphere ray-tracing technique, we study GW magnification effect and selection with particular attention stellar-mass binary black holes (BBHs). We find that, for observed luminosity $\lesssim 3~\mathrm{Gpc}$, which is aLIGO/Virgo observational horizon limit, average keeps as unity, namely unbiased estimation, relative...
We propose a novel method to detect cosmic magnification signals by cross-correlating foreground convergence fields constructed from galaxy shear measurements with background positional distributions---namely, shear-number density correlation. apply it the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) survey data. With 27 nonindependent data points and their full covariance, ${\ensuremath{\chi}}_{0}^{2}\ensuremath{\approx}34.1$ ${\ensuremath{\chi}}_{T}^{2}\ensuremath{\approx}24.0$...
The convergence peaks, constructed from galaxy shape measurement in weak lensing, is a powerful probe of cosmology as the peaks can be connected with underlined dark matter haloes. However capability peak statistic affected by noise measurement, signal to ratio well contribution projected mass distribution large-scale structures along line sight (LOS). In this paper we use ray-tracing simulation on curved sky investigate correspondence between and haloes at LOS. We find that, case no for...
It has been shown, both in simulations and observationally, that the tidal field of a large galaxy can torque its satellites such major axis satellite galaxies points towards their hosts. This so-called `shape alignment' observed isolated Milky Way-like but not `Local Group'-like pairs. In this study, we investigate shape alignment pairs similar to Local Group identified Sloan Digital Sky Survey Data Release 13 (SDSS DR13). By stacking tens thousands around primary pairs, find two...
ABSTRACT Accurate shear measurement is a key topic in weak lensing community. Point spread function (PSF), which smears the observed galaxy image, plays one of main roles systematic errors and must be treated carefully to avoid bias cosmological parameters. In this paper, we present new PSF methods, Smooth-PCA (SPCA) Improved-SPCA (iSPCA), can reconstruct smooth PSFs with high efficiency. Our methods decompose star images into principal components by using Expectation-Maximization-PCA...
Weak gravitational lensing is one of the most important probes nature dark matter and energy. In order to extract cosmological information from next-generation weak surveys (e.g., Euclid, Roman, LSST, CSST) as much possible, accurate measurements shear are required. There existing algorithms measure on imaging data, which have been successfully applied in previous surveys. meantime, machine learning (ML) has widely recognized various astrophysics applications modeling observations. this...
Abstract Images taken by space telescopes typically have a superb spatial resolution, but relatively poor sampling rate due to the finite CCD pixel size. Beyond Nyquist limit, it becomes uncertain how much pixelation effect may affect accuracy of galaxy shape measurement. It is timely study this issue given that number space-based large-scale weak lensing surveys are planned. Using Fourier_Quad method, we quantify shear recovery error as function factor Q , i.e., ratio between FWHM...
Void size function (VSF) contains the information of cosmic large-scale structure (LSS), and can be used to derive properties dark energy matter. We predict VSFs measured from spectroscopic galaxy survey operated by China Space Station Telescope (CSST), study strength cosmological constraint. employ a high-resolution Jiutian simulation get samples based on an improved semi-analytical model, then generate mock catalog CSST according detection sensitivity. identify voids this using watershed...
We investigate emission line galaxies across cosmic time by combining the modified L-Galaxies semi-analytical galaxy formation model with JiuTian cosmological simulation. improve tidal disruption of satellite in to address dependence problem. utilise public code CLOUDY compute ratios for a grid HII region models. The models assume same initial mass function as that used generate spectral energy distribution galaxies, ensuring coherent treatment modelling full spectrum. By incorporating these...
Strong gravitational lensing is a powerful tool for investigating dark matter and energy properties. With the advent of large-scale sky surveys, we can discover strong systems on an unprecedented scale, which requires efficient tools to extract them from billions astronomical objects. The existing mainstream lens-finding are based machine learning algorithms applied cut-out-centered galaxies. However, according design survey strategy optical surveys by CSST, preparing cutouts with multiple...