China Space Station Telescope (CSST) is a forthcoming powerful Stage IV space-based optical survey equipment. It is expected to explore a number of important cosmological problems in extremely high precision. In this work, we focus on... more
China Space Station Telescope (CSST) is a forthcoming powerful Stage IV space-based optical survey equipment. It is expected to explore a number of important cosmological problems in extremely high precision. In this work, we focus on investigating the constraints on neutrino mass and other cosmological parameters under the model of cold dark matter with a constant equation of state of dark energy (wCDM), using the mock data from the CSST photometric galaxy clustering and cosmic shear surveys (i.e. 3 × 2 pt). The systematics from galaxy bias, photometric redshift uncertainties, intrinsic alignment, shear calibration, baryonic feedback, non-linear, and instrumental effects are also included in the analysis. We generate the mock data based on the COSMOS catalogue considering the instrumental and observational effects of the CSST, and make use of the Markov chain Monte Carlo method to perform the constraints. Comparing to the results from current similar measurements, we find that CSST...
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The Brans–Dicke (BD) theory is the simplest Scalar-Tensor theory of gravity, which can be considered as a candidate of modified Einstein’s theory of general relativity. In this work, we forecast the constraints on BD theory in the CSST... more
The Brans–Dicke (BD) theory is the simplest Scalar-Tensor theory of gravity, which can be considered as a candidate of modified Einstein’s theory of general relativity. In this work, we forecast the constraints on BD theory in the CSST galaxy clustering spectroscopic survey with a magnitude limit ∼23 AB mag for point-source 5σ detection. We generate mock data based on the zCOSMOS catalog and consider the observational and instrumental effects of the CSST spectroscopic survey. We predict galaxy power spectra in the BD theory from z = 0 to 1.5, and the galaxy bias and other systematical parameters are also included. The Markov Chain Monte Carlo technique is employed to find the best-fits and probability distributions of the cosmological and systematical parameters. A BD parameter ζ is introduced, which satisfies ζ = ln 1 + 1 ω . We find that the CSST spectroscopic galaxy clustering survey can give ∣ζ∣ < 10−2, or equivalently ∣ ω ∣ > ( 10 2 ) and ∣ G ̇ / G ∣ < 10 − 13 , unde...
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The China Space Station Telescope (CSST) photometric survey aims to perform a high spatial resolution (∼0.″15) photometric imaging for the targets that cover a large sky area (∼17,500 deg2) and wide wavelength range (from NUV to NIR). It... more
The China Space Station Telescope (CSST) photometric survey aims to perform a high spatial resolution (∼0.″15) photometric imaging for the targets that cover a large sky area (∼17,500 deg2) and wide wavelength range (from NUV to NIR). It expects to explore the properties of dark matter, dark energy, and other important cosmological and astronomical areas. In this work, we evaluate whether the filter design of the Multi-channel Imager (MCI), one of the five instruments of the CSST, can provide accurate photometric redshift (photoz) measurements with its nine medium-band filters to meet the relevant scientific objectives. We generate the mock data based on the COSMOS photometric redshift catalog with astrophysical and instrumental effects. The application of upper limit information of low signal-to-noise ratio data is adopted in the estimation of photoz. We investigate the dependency of photoz accuracy on the filter parameters, such as band position and width. We find that the current...
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Contamination of interloper galaxies due to misidentified emission lines can be a big issue in spectroscopic galaxy-clustering surveys, especially in future high-precision observations. We propose a statistical method based on the cross... more
Contamination of interloper galaxies due to misidentified emission lines can be a big issue in spectroscopic galaxy-clustering surveys, especially in future high-precision observations. We propose a statistical method based on the cross correlations of the observational data between two redshift bins to efficiently reduce this effect, and it can also derive the interloper fraction f i in a redshift bin with a high level of accuracy. The ratio of cross and autoangular 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 China Space Station Telescope. We find that this method can effectively reduce the interloper effect, and accurately constrain the cosmological parameters fo...
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We confront the universal pressure profile (UPP) proposed. with the recent measurement of the cross-correlation function of the thermal Sunyaev–Zeldovich (tSZ) effect from Planck and weak gravitational lensing measurement from the Red... more
We confront the universal pressure profile (UPP) proposed. with the recent measurement of the cross-correlation function of the thermal Sunyaev–Zeldovich (tSZ) effect from Planck and weak gravitational lensing measurement from the Red Cluster Sequence Lensing Survey. By using the halo model, we calculate the prediction of ξy−κ (lensing convergence and Compton-y parameter) and $\xi ^{y-\gamma _{\rm t}}$ (lensing shear and Compton-y parameter) and fit the UPP parameters by using the observational data. We find consistent UPP parameters when fixing the cosmology to either WMAP 9-yr or Planck 2018 best-fitting values. The best constrained parameter is the pressure profile concentration c500 = r500/rs, for which we find $c_{500} = 2.68^{+1.46}_{-0.96}$ (WMAP-9) and $c_{500} = 1.91^{+1.07}_{-0.65}$ (Planck-2018) for the $\xi ^{y-\gamma _t}$ estimator. The shape index for the intermediate radius region α parameter is constrained to $\alpha =1.75^{+1.29}_{-0.77}$ and $\alpha = 1.65^{+0.74}_...
Research Interests: Physics and Astrophysics
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The spatial fluctuations of the extragalactic background light trace the total emission from all stars and galaxies in the Universe. A multiwavelength study can be used to measure the integrated emission from first galaxies during... more
The spatial fluctuations of the extragalactic background light trace the total emission from all stars and galaxies in the Universe. A multiwavelength study can be used to measure the integrated emission from first galaxies during reionization when the Universe was about 500 million years old. Here we report arcmin-scale spatial fluctuations in one of the deepest sky surveys with the Hubble Space Telescope in five wavebands between 0.6 and 1.6 μm. We model-fit the angular power spectra of intensity fluctuation measurements to find the ultraviolet luminosity density of galaxies at redshifts greater than 8 to be . This level of integrated light emission allows for a significant surface density of fainter primeval galaxies that are below the point-source detection level in current surveys.
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Extragalactic background light (EBL) anisotropy traces variations in the total production of photons over cosmic history and may contain faint, extended components missed in galaxy point-source surveys. Infrared EBL fluctuations have been... more
Extragalactic background light (EBL) anisotropy traces variations in the total production of photons over cosmic history and may contain faint, extended components missed in galaxy point-source surveys. Infrared EBL fluctuations have been attributed to primordial galaxies and black holes at the epoch of reionization (EOR) or, alternately, intrahalo light (IHL) from stars tidally stripped from their parent galaxies at low redshift. We report new EBL anisotropy measurements from a specialized sounding rocket experiment at 1.1 and 1.6 micrometers. The observed fluctuations exceed the amplitude from known galaxy populations, are inconsistent with EOR galaxies and black holes, and are largely explained by IHL emission. The measured fluctuations are associated with an EBL intensity that is comparable to the background from known galaxies measured through number counts and therefore a substantial contribution to the energy contained in photons in the cosmos.
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Research Interests: Mathematical Physics, Physics, Quantum Physics, Particle Physics, Dark Matter, and 11 moreEquations of State, Dark Energy, Cosmic Microwave Background, Models, Baryon Acoustic Oscillations, Cold Dark Matter, Physical Model, Cosmic Microwave Background Radiation, Equation of State, Elementary Particles, and baryons
We use the current weak lensing data to constrain the equation of state of dark energy w and the total mass of massive neutrinos ∑ mν. The constraint on w would be weak if only the current weak lensing data are used. With the addition of... more
We use the current weak lensing data to constrain the equation of state of dark energy w and the total mass of massive neutrinos ∑ mν. The constraint on w would be weak if only the current weak lensing data are used. With the addition of other observational data such as ...
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Abstract: A large sub-mm survey with Herschel will enable many exciting science opportunities, especially in an era of wide-field optical and radio surveys and high resolution cosmic microwave background experiments. The Herschel-SPIRE... more
Abstract: A large sub-mm survey with Herschel will enable many exciting science opportunities, especially in an era of wide-field optical and radio surveys and high resolution cosmic microwave background experiments. The Herschel-SPIRE Legacy Survey (HSLS), will lead to imaging data over 4000 sq. degrees at 250, 350, and 500 micron. Major Goals of HSLS are:(a) produce a catalog of 2.5 to 3 million galaxies down to 26, 27 and 33 mJy (50% completeness; 5 sigma confusion noise) at 250, 350 and 500 micron, respectively, in the ...