اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدConstraining the growth rate of structure with phase correlations
112
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We show that correlations between the phases of the galaxy density field in redshift space provide additional information about the growth rate of large-scale structure that is complementary to the power spectrum multipoles. In particular, we consider the multipoles of the line correlation function (LCF), which correlates phases between three collinear points, and use the Fisher forecasting method to show that the LCF multipoles can break the degeneracy between the measurement of the growth rate of structure $f$ and the amplitude of perturbations $sigma_8$ that is present in the power spectrum multipoles at large scales. This leads to an improvement in the measurement of $f$ and $sigma_8$ by up to 220 per cent for $k_{rm max} = 0.15 , hmathrm{Mpc}^{-1}$ and up to 50 per cent for $k_{rm max} = 0.30 , hmathrm{Mpc}^{-1}$ at redshift $z=0.25$, with respect to power spectrum measurements alone for the upcoming generation of galaxy surveys like DESI and Euclid. The average improvements in the constraints on $f$ and $sigma_8$ for $k_{rm max} = 0.15 , hmathrm{Mpc}^{-1}$ are $sim 90$ per cent for the DESI BGS sample with mean redshift $overline{z}=0.25$, $sim 40$ per cent for the DESI ELG sample with $overline{z}=1.25$, and $sim 40$ per cent for the Euclid H$alpha$ galaxies with $overline{z}=1.3$. For $k_{rm max} = 0.30 , hmathrm{Mpc}^{-1}$, the average improvements are $sim 40$ per cent for the DESI BGS sample and $sim 20$ per cent for both the DESI ELG and Euclid H$alpha$ galaxies.
قيم البحث
اقرأ أيضاً
Redshift-space clustering distortions provide one of the most powerful probes to test the gravity theory on the largest cosmological scales. We perform a systematic validation study of the state-of-the-art statistical methods currently used to constr
ain the linear growth rate from redshift-space distortions in the galaxy two-point correlation function. The numerical pipelines are tested on mock halo catalogues extracted from large N-body simulations of the standard cosmological framework. We consider both the monopole and quadrupole multipole moments of the redshift-space two-point correlation function, as well as the radial and transverse clustering wedges, in the comoving scale range $10<r[$Mpch$]<55$. Moreover, we investigate the impact of redshift measurement errors on the growth rate and linear bias measurements due to the assumptions in the redshift-space distortion model. Considering both the dispersion model and two widely-used models based on perturbation theory, we find that the linear growth rate is underestimated by about $5-10%$ at $z<1$, while limiting the analysis at larger scales, $r>30$ Mpch, the discrepancy is reduced below $5%$. At higher redshifts, we find instead an overall good agreement between measurements and model predictions. Though this accuracy is good enough for clustering analyses in current redshift surveys, the models have to be further improved not to introduce significant systematics in RSD constraints from next generation galaxy surveys. The effect of redshift errors is degenerate with the one of small-scale random motions, and can be marginalised over in the statistical analysis, not introducing any statistically significant bias in the linear growth constraints, especially at $zgeq1$.
A recently proposed technique allows one to constrain both the background and perturbation cosmological parameters through the distribution function of supernova Ia apparent magnitudes. Here we extend this technique to alternative cosmological scenar
ios, in which the growth of structure does not follow the $Lambda$CDM prescription. We apply the method first to the supernova data provided by the JLA catalog combined with all the current independent redshift distortion data and with low-redshift cluster data from Chandra and show that although the supernovae alone are not very constraining, they help in reducing the confidence regions. Then we apply our method to future data from LSST and from a survey that approximates the Euclid satellite mission. In this case we show that the combined data are nicely complementary and can constrain the normalization $sigma_8$ and the growth rate index $gamma$ to within $0.6%$ and $7%$, respectively. In particular, the LSST supernova catalog is forecast to give the constraint $gamma (sigma_8/0.83)^{6.7} = 0.55 pm 0.1$. We also report on constraints relative to a step-wise parametrization of the growth rate of structures. These results show that supernova lensing serves as a good cross-check on the measurement of perturbation parameters from more standard techniques.
We present an improved framework for estimating the growth rate of large-scale structure, using measurements of the galaxy-velocity cross-correlation in configuration space. We consider standard estimators of the velocity auto-correlation function, $
psi_1$ and $psi_2$, the two-point galaxy correlation function, $xi_{gg}$, and introduce a new estimator of the galaxy-velocity cross-correlation function, $psi_3$. By including pair counts measured from random catalogues of velocities and positions sampled from distributions characteristic of the true data, we find that the variance in the galaxy-velocity cross-correlation function is significantly reduced. Applying a covariance analysis and $chi^2$ minimisation procedure to these statistics, we determine estimates and errors for the normalised growth rate $fsigma_8$ and the parameter $beta = f/b$, where $b$ is the galaxy bias factor. We test this framework on mock hemisphere datasets for redshift $z < 0.1$ with realistic velocity noise constructed from the L-PICOLA simulation code, and find that we are able to recover the fiducial value of $fsigma_8$ from the joint combination of $psi_1$ + $psi_2$ + $psi_3$ + $xi_{gg}$, with 15% accuracy from individual mocks. We also recover the fiducial $fsigma_8$ to within 1$sigma$ regardless of the combination of correlation statistics used. When we consider all four statistics together we find that the statistical uncertainty in our measurement of the growth rate is reduced by $59%$ compared to the same analysis only considering $psi_2$, by $53%$ compared to the same analysis only considering $psi_1$, and by $52%$ compared to the same analysis jointly considering $psi_1$ and $psi_2$.
We investigate the interacting dark energy models by using the diagnostics of statefinder hierarchy and growth rate of structure. We wish to explore the deviations from $Lambda$CDM and to differentiate possible degeneracies in the interacting dark en
ergy models with the geometrical and structure growth diagnostics. We consider two interacting forms for the models, i.e., $Q_1=beta Hrho_c$ and $Q_2=beta Hrho_{de}$, with $beta$ being the dimensionless coupling parameter. Our focus is the I$Lambda$CDM model that is a one-parameter extension to $Lambda$CDM by considering a direct coupling between the vacuum energy ($Lambda$) and cold dark matter (CDM), with the only additional parameter $beta$. But we begin with a more general case by considering the I$w$CDM model in which dark energy has a constant $w$ (equation-of-state parameter). For calculating the growth rate of structure, we employ the parametrized post-Friedmann theoretical framework for interacting dark energy to numerically obtain the $epsilon(z)$ values for the models. We show that in both geometrical and structural diagnostics the impact of $w$ is much stronger than that of $beta$ in the I$w$CDM model. We thus wish to have a closer look at the I$Lambda$CDM model by combining the geometrical and structural diagnostics. We find that the evolutionary trajectories in the $S^{(1)}_3$--$epsilon$ plane exhibit distinctive features and the departures from $Lambda$CDM could be well evaluated, theoretically, indicating that the composite null diagnostic ${S^{(1)}_3, epsilon}$ is a promising tool for investigating the interacting dark energy models.
In this paper, we constrain the dimensionless Compton wavelength parameter $B_0$ of $f(R)$ gravity as well as the mass of sterile neutrino by using the cosmic microwave background observations, the baryon acoustic oscillation surveys, and the linear
growth rate measurements. Since both the $f(R)$ model and the sterile neutrino generally predict scale-dependent growth rates, we utilize the growth rate data measured in different wavenumber bins with the theoretical growth rate approximatively scale-independent in each bin. The employed growth rate data come from the peculiar velocity measurements at $z=0$ in five wavenumber bins, and the redshift space distortions measurements at $z=0.25$ and $z=0.37$ in one wavenumber bin. By constraining the $f(R)$ model alone, we get a tight 95% upper limit of $log_{10}B_0<-4.1$. This result is slightly weakened to $log_{10}B_0<-3.8$ (at 2$sigma$ level) once we simultaneously constrain the $f(R)$ model and the sterile neutrino mass, due to the degeneracy between the parameters of the two. For the massive sterile neutrino parameters, we get the effective sterile neutrino mass $m_{ u,{rm{sterile}}}^{rm{eff}}<0.62$ eV (2$sigma$) and the effective number of relativistic species $N_{rm eff}<3.90$ (2$sigma$) in the $f(R)$ model. As a comparison, we also obtain $m_{ u,{rm{sterile}}}^{rm{eff}}<0.56$ eV (2$sigma$) and $N_{rm eff}<3.92$ (2$sigma$) in the standard $Lambda$CDM model.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
