From Baryon Acoustic Oscillation measurements with Sloan Digital Sky Survey SDSS DR14 galaxies, and the acoustic horizon angle measured by the Planck Collaboration, we obtain Ωm=0.2724±0.0047, and h+0.020&sd...From Baryon Acoustic Oscillation measurements with Sloan Digital Sky Survey SDSS DR14 galaxies, and the acoustic horizon angle measured by the Planck Collaboration, we obtain Ωm=0.2724±0.0047, and h+0.020⋅∑mv=0.7038±0.0060, assuming flat space and a cosmological constant. We combine this result with the 2018 Planck “TT, TE, EE + lowE + lensing” analysis, and update a study of ∑mv with new direct measurements of σ8, and obtain ∑mv=0.27±0.08 eV assuming three nearly degenerate neutrino eigenstates. Measurements are consistent with Ωk=0, and Ωde(a)=ΩΛ constant.展开更多
We measure the baryon acoustic oscillation (BAO) observables , , and as a function of red shift z in the range 0.1 to 0.7 with Sloan Digital Sky Survey (SDSS) data release DR13. These observables are independent and s...We measure the baryon acoustic oscillation (BAO) observables , , and as a function of red shift z in the range 0.1 to 0.7 with Sloan Digital Sky Survey (SDSS) data release DR13. These observables are independent and satisfy a consistency relation that provides discrimination against miss-fits due to background fluctuations. From these measurements and the correlation angle of fluctuations of the Cosmic Microwave Background (CMB), we obtain , and for dark energy density allowed to vary as . We present measurements of at six values of the expansion parameter a. Fits with several scenarios and data sets are presented. The data is consistent with space curvature parameter? and constant.展开更多
We investigate what role the SKA neutral hydrogen(HI)intensity mapping(IM)and galaxy sky surveys will play in weighing neutrinos in cosmology.We use the simulated data of the baryon acoustic oscillation(BAO)measuremen...We investigate what role the SKA neutral hydrogen(HI)intensity mapping(IM)and galaxy sky surveys will play in weighing neutrinos in cosmology.We use the simulated data of the baryon acoustic oscillation(BAO)measurements from the HI surveys based on SKA1(IM)and SKA2(galaxy)to do the analysis.For the current observations,we use the Planck 2015 cosmic microwave background(CMB)anisotropies observation,the optical BAO measurements,the type Ia supernovae(SN)observation(Pantheon compilation),and the latest H0 measurement.We consider three mass ordering cases for massive neutrinos,i.e.,the normal hierarchy(NH),inverted hierarchy(IH),and degenerate hierarchy(DH)cases.It is found that the SKA observation can significantly improve the constraints on?m and H0.Compared to the current observation,the SKA1 data can improve the constraints on?m by about 33%,and on H0 by about 36%;the SKA2 data can improve the constraints on?m by about 58%,and on H0 by about 66%.It is also found that the SKA observation can only slightly improve the constraints on∑mν.Compared to the current observation,the SKA1 data can improve the constraints on∑mνby about 4%,3%,and 10%,for the NH,IH,and DH cases,respectively;the SKA2 data can improve the constraints on∑mνby about 7%,7%,and 16%,for the NH,IH,and DH cases,respectively.展开更多
Galaxy redshift surveys are one of the key probes in modern cosmology.In the data analysis of galaxy surveys,the precision of the statistical measurement is primarily limited by the cosmic variance on large scales.For...Galaxy redshift surveys are one of the key probes in modern cosmology.In the data analysis of galaxy surveys,the precision of the statistical measurement is primarily limited by the cosmic variance on large scales.Fortunately,this limitation can in principle be mitigated by observing multiple types of biased tracers.In this brief review,we present the idea of the multi-tracer method,outline key steps in the data analysis and show several worked examples based on the GAMA,BOSS and e BOSS galaxy surveys.This work is a part of a special issue dedicated to the 20 th anniversary of RAA(2001–2020),which is prefaced in Wang&Ip(2020).展开更多
文摘From Baryon Acoustic Oscillation measurements with Sloan Digital Sky Survey SDSS DR14 galaxies, and the acoustic horizon angle measured by the Planck Collaboration, we obtain Ωm=0.2724±0.0047, and h+0.020⋅∑mv=0.7038±0.0060, assuming flat space and a cosmological constant. We combine this result with the 2018 Planck “TT, TE, EE + lowE + lensing” analysis, and update a study of ∑mv with new direct measurements of σ8, and obtain ∑mv=0.27±0.08 eV assuming three nearly degenerate neutrino eigenstates. Measurements are consistent with Ωk=0, and Ωde(a)=ΩΛ constant.
文摘We measure the baryon acoustic oscillation (BAO) observables , , and as a function of red shift z in the range 0.1 to 0.7 with Sloan Digital Sky Survey (SDSS) data release DR13. These observables are independent and satisfy a consistency relation that provides discrimination against miss-fits due to background fluctuations. From these measurements and the correlation angle of fluctuations of the Cosmic Microwave Background (CMB), we obtain , and for dark energy density allowed to vary as . We present measurements of at six values of the expansion parameter a. Fits with several scenarios and data sets are presented. The data is consistent with space curvature parameter? and constant.
基金supported by the National Natural Science Foundation of China(Grant Nos.11875102,11835009,11975072,11690021,and 11522540)the Liaoning Revitalization Talents Program(Grant No.XLYC1905011)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.N2005030)the National Program for Support of Top-Notch Young Professionals。
文摘We investigate what role the SKA neutral hydrogen(HI)intensity mapping(IM)and galaxy sky surveys will play in weighing neutrinos in cosmology.We use the simulated data of the baryon acoustic oscillation(BAO)measurements from the HI surveys based on SKA1(IM)and SKA2(galaxy)to do the analysis.For the current observations,we use the Planck 2015 cosmic microwave background(CMB)anisotropies observation,the optical BAO measurements,the type Ia supernovae(SN)observation(Pantheon compilation),and the latest H0 measurement.We consider three mass ordering cases for massive neutrinos,i.e.,the normal hierarchy(NH),inverted hierarchy(IH),and degenerate hierarchy(DH)cases.It is found that the SKA observation can significantly improve the constraints on?m and H0.Compared to the current observation,the SKA1 data can improve the constraints on?m by about 33%,and on H0 by about 36%;the SKA2 data can improve the constraints on?m by about 58%,and on H0 by about 66%.It is also found that the SKA observation can only slightly improve the constraints on∑mν.Compared to the current observation,the SKA1 data can improve the constraints on∑mνby about 4%,3%,and 10%,for the NH,IH,and DH cases,respectively;the SKA2 data can improve the constraints on∑mνby about 7%,7%,and 16%,for the NH,IH,and DH cases,respectively.
基金supported by the National Key Basic Research and Development Program of China(No.2018YFA0404503)a grant from the CAS Interdisciplinary Innovation Team.YW is supported by the Nebula Talents Program of NAOCsupported by the National Natural Science Foundation of China(Grant Nos.11925303,11720101004,11673025 and 11890691)。
文摘Galaxy redshift surveys are one of the key probes in modern cosmology.In the data analysis of galaxy surveys,the precision of the statistical measurement is primarily limited by the cosmic variance on large scales.Fortunately,this limitation can in principle be mitigated by observing multiple types of biased tracers.In this brief review,we present the idea of the multi-tracer method,outline key steps in the data analysis and show several worked examples based on the GAMA,BOSS and e BOSS galaxy surveys.This work is a part of a special issue dedicated to the 20 th anniversary of RAA(2001–2020),which is prefaced in Wang&Ip(2020).
