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相关论文: Large-Scale Mass Power Spectrum from Peculiar Velo…

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We present cosmological parameters measurements from the full combination of DESI DR1 galaxy clustering data described with large-scale structure effective field theory. By incorporating additional datasets (photometric galaxies and CMB…

宇宙学与河外天体物理 · 物理学 2026-01-23 Mikhail M. Ivanov , James M. Sullivan , Shi-Fan Chen , Anton Chudaykin , Mark Maus , Oliver H. E. Philcox

Peculiar velocities of clusters of galaxies can be measured by studying the fluctuations in the cosmic microwave background (CMB) generated by the scattering of the microwave photons by the hot X-ray emitting gas inside clusters. While for…

天体物理学 · 物理学 2010-11-26 A. Kashlinsky , F. Atrio-Barandela , D. Kocevski , H. Ebeling

Using N-body simulations, we measure the power spectrum of the effective dark matter density field, which is defined through the modified Poisson equation in $f(R)$ cosmologies. We find that when compared to the conventional dark matter…

宇宙学与河外天体物理 · 物理学 2015-11-11 Jian-hua He , Baojiu Li , Adam J. Hawken

We present a numerical approach for estimating the probability density function (PDF) of quantities of interest (QoIs) of power grid systems subject to uncertain power generation and load fluctuations. In our approach, generation and load…

The perturbative approach to structure formation has recently received a lot of attention in the literature. In such setups the final predictions for observables like the power spectrum is often derived under additional approximations such…

宇宙学与河外天体物理 · 物理学 2016-12-14 Matteo Fasiello , Zvonimir Vlah

In the early Universe, energy stored in small-scale density perturbations is quickly dissipated by Silk-damping, a process that inevitably generates mu- and y-type spectral distortions of the cosmic microwave background (CMB). These…

宇宙学与河外天体物理 · 物理学 2015-06-04 Jens Chluba , Adrienne L. Erickcek , Ido Ben-Dayan

The power spectral density of an observable quantifies the amount of fluctuations at a given frequency and can reveal the influence of different timescales on the observable's dynamics. Here, we show that the spectral density in a…

统计力学 · 物理学 2023-06-02 Andreas Dechant

The possibility of detecting weak lensing effects from deep wide field imaging surveys has open new means of probing the large-scale structures of the Universe and measuring cosmological parameters. In this paper we present a systematic…

天体物理学 · 物理学 2010-04-06 F. Bernardeau , L. van Waerbeke , Y. Mellier

In this paper we evaluate the spectrum of the pregalactic density field on scales $1h^{-1}Mpc < r < 100h^{-1}$Mpc from a variety of astronomical data. APM data on $w(\theta)$ in six narrow magnitude is used, after correcting to possible…

天体物理学 · 物理学 2009-10-30 A. Kashlinsky

We compare the predictions of hybrid inflationary models that produce both adiabatic fluctuations and topological defects to first year WMAP results. We use a Markov Chain Monte Carlo method to constrain the contribution of cosmic strings…

天体物理学 · 物理学 2007-05-23 Aurélien A. Fraisse

We present estimates of cosmological parameters from the application of the Karhunen-Loeve transform to the analysis of the 3D power spectrum of density fluctuations using Sloan Digital Sky Survey galaxy redshifts. We use Omega_m*h and f_b…

We apply the scale-length method to several three dimensional samples of the Two degree Field Galaxy Redshift Survey. This method allows us to map in a quantitative and powerful way large scale structures in the distribution of galaxies…

天体物理学 · 物理学 2009-08-03 Francesco Sylos Labini , Nikolay L. Vasilyev , Yurij V. Baryshev

The normalisation of the matter power spectrum, sigma_8, is an essential ingredient to predict the phenomenology of the low redshift universe. It has been measured using several methods, such as X-ray cluster counts, weak lensing and the…

天体物理学 · 物理学 2008-11-26 A. Amara , A. Refregier

We implement and investigate a method for measuring departures from scale-invariance, both scale-dependent as well as scale-free, in the primordial power spectrum of density perturbations using cosmic microwave background (CMB) C_l data and…

天体物理学 · 物理学 2009-11-11 Samuel Leach

It is widely believed that maximum likelihood estimators must be used to provide optimal estimates of power spectra. Since such estimators require require of order N_d^3 operations they are computationally prohibitive for N_d greater than a…

天体物理学 · 物理学 2008-11-26 G. Efstathiou

Quantitative description of the statistics of intensity fluctuations within spectral line data cubes introduced in our earlier work is extended to the absorbing media. A possibility of extracting 3D velocity and density statistics from both…

天体物理学 · 物理学 2009-11-10 A. Lazarian , D. Pogosyan

We explore constraints on dark energy and modified gravity with forecast 21cm intensity mapping measurements using the Effective Field Theory approach. We construct a realistic mock data set forecasting a low redshift 21cm signal power…

宇宙学与河外天体物理 · 物理学 2022-01-19 Maria Berti , Marta Spinelli , Balakrishna S. Haridasu , Matteo Viel , Alessandra Silvestri

We analyze the SDSS Ly-alpha forest P_F(k,z) measurement to determine the linear theory power spectrum. Our analysis is based on fully hydrodynamic simulations, extended using hydro-PM simulations. We account for the effect of absorbers…

We have made a likelihood statistical analysis of the angular correlations in the {\it COBE}-DMR two-year sky maps by Monte Carlo simulation of the temperature fluctuations. We assume an open universe and consider as primordial power…

天体物理学 · 物理学 2015-06-24 L. Cayon , E. Martinez-Gonzalez , J. L. Sanz , N. Sugiyama , S. Torres

We present a new method of measuring the power spectrum of initial perturbations to an unprecedently small scale of $\sim$ 10$h^{-1}$ kpc. We apply this method to a sample of 4500 Ly-$\alpha$ absorbers and recover the cold dark matter (CDM)…

天体物理学 · 物理学 2009-11-07 M. Demiański , A. G. Doroshkevich