scholarly journals Estimating Power Spectrum of Sunyaev‐Zeldovich Effect from the Cross‐Correlation between theWilkinson Microwave Anistropy Probeand the Two Micron All Sky Survey

2007 ◽  
Vol 661 (2) ◽  
pp. 641-649 ◽  
Author(s):  
Liang Cao ◽  
Jiren Liu ◽  
Li‐Zhi Fang
Keyword(s):  
Power Spectrum ◽  
Cross Correlation ◽  
Sky Survey ◽  
The Cross

scholarly journals HIR4: cosmological signatures imprinted on the cross-correlation between a 21-cm map and galaxy clustering

2020 ◽  
Vol 499 (4) ◽  
pp. 4613-4625
Author(s):  
Feng Shi ◽  
Yong-Seon Song ◽  
Jacobo Asorey ◽  
David Parkinson ◽  
Kyungjin Ahn ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Cross Correlation ◽  
Broad Band ◽  
Power Spectra ◽  
Acoustic Oscillation ◽  
Particle Simulation ◽  
Band Shape ◽  
Angular Diameter Distance ◽  
Instrument Noise ◽  
The Cross

ABSTRACT We explore the cosmological multitracer synergies between an emission-line galaxy distribution from the Dark Energy Spectroscopic Instrument and a Tianlai Project 21-cm intensity map. We use simulated maps generated from a particle simulation in the light-cone volume (Horizon Run 4), sky-trimmed and including the effects of foreground contamination, its removal and instrument noise. We first validate how the foreground residual affects the recovered 21-cm signal by putting different levels of foreground contamination into the 21-cm maps. We find that the contamination cannot be ignored in the angular autocorrelation power spectra of H i even when it is small, but it has no influence on the accuracy of the angular cross-correlation power spectra between H i and galaxies. In the foreground-cleaned map case, as information is lost in the cleaning procedure, there is also a bias in the cross-correlation power spectrum. However, we found that the bias from the cross-correlation power spectrum is scale-independent, which is easily parametrized as part of the model, while the offset in the H i autocorrelation power spectrum is non-linear. In particular, we tested that the cross-correlation power also benefits from the cancellation of the bias in the power spectrum measurement that is induced by the instrument noise, which changes the shape of the autocorrelation power spectra but leaves the cross-correlation power spectra unaffected. We then modelled the angular cross-correlation power spectra to fit the baryon acoustic oscillation feature in the broad-band shape of the angular cross-correlation power spectrum, including contamination from the residual foreground and the effect of instrument noise. We forecast a constraint on the angular diameter distance DA for the Tianlai Pathfinder redshift 0.775 < z < 1.03, giving a distance measurement with a precision of 2.7 per cent at that redshift.

Polarity Change Extraction of GPR Data for Under-road Cavity Detection: Application on Sudeoksa Testbed Data

2019 ◽  
Vol 24 (3) ◽  
pp. 419-431
Author(s):  
Jongha Hwang ◽  
Donggeon Kim ◽  
Xiangyue Li ◽  
Dong-Joo Min
Keyword(s):  
Phase Shift ◽  
Power Spectrum ◽  
Cross Correlation ◽  
Survey Methods ◽  
Time Lag ◽  
Background Signal ◽  
Data Set ◽  
Air Ground Interface ◽  
The Cross ◽  
Polarity Change

Ground penetrating radar (GPR) is one of the most widely used geophysical survey methods to locate cavities under roads due to its speedy exploration and high-resolution imaging. To locate underground cavities using GPR, we need to distinguish between cavity-induced reflections and other reflections, which can be achieved by examining the polarity change in reflections compared to the polarity of the transmitted signal. The polarity change can be measured from the phase shift between the target and first reflections. To estimate the phase shift in reflections, the method of computing the power spectrum difference between the original trace and background signal was proposed, but the method has a limitation for shallow reflectors. As an alternative method to avoid this limitation, we propose using only one component of the power spectrum difference, the cross-correlation between the target reflection and background signal. The cross-correlation has its maximum peak at a time lag between the target and first reflection (from the air-ground interface). Additionally, the phase at that time lag represents a phase shift between the two reflections. We compare our cross-correlation-based method with the conventional method of computing the whole power spectrum difference and investigate the feasibility of our method for distinguishing cavity-induced reflections using a 2D field data set acquired in a testbed in Sudeoksa, Korea.

scholarly journals Cross-correlation between cosmological and astrophysical datasets: the Planck and Herschel case

2014 ◽  
Vol 10 (S306) ◽  
pp. 202-205 ◽  
Author(s):  
Federico Bianchini ◽  
Andrea Lapi
Keyword(s):  
Power Spectrum ◽  
Cross Correlation ◽  
Forthcoming Paper ◽  
Joint Analysis ◽  
Atlas Data ◽  
Λcdm Model ◽  
The Galaxy ◽  
The Cross ◽  
Galaxy Bias ◽  
Cross Power Spectrum

AbstractWe present the first measurement of the correlation between the map of the CMB lensing potential derived from the Planck nominal mission data and z ≳ 1.5 galaxies detected by Herschel-ATLAS (H-ATLAS) survey covering about 550 deg2. We detect the cross-power spectrum with a significance of ∼ 8.5σ, ruling out the absence of correlation at 9σ. We check detection with a number of null tests. The amplitude of cross-correlation and the galaxy bias are estimated using joint analysis of the cross-power spectrum and the galaxy survey auto-spectrum, which allows to break degeneracy between these parameters. The estimated galaxy bias is consistent with previous estimates of the bias for the H-ATLAS data, while the cross-correlation amplitude is higher than expected for a ΛCDM model. The content of this work is to appear in a forthcoming paper Bianchini, et al. (2014).

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