3,480 research outputs found
Cosmic Microwave Background-Weak Lensing Correlation: Analytical and Numerical Study of Nonlinearity and Implications for Dark Energy
Evolution of density fluctuations yields secondary anisotropies in the cosmic microwave background ( CMB), which are correlated with the same density fluctuations that can be measured by weak lensing (WL) surveys. We study the CMB-WL correlation induced by the integrated Sachs-Wolfe (ISW) effect and its nonlinear extension, the Rees-Sciama (RS) effect, using analytical models as well as N-body simulations. We show that an analytical model based on the time derivative of matter power spectrum agrees with simulations. All-sky cosmic-variance-limited CMB and WL surveys allow us to measure the correlation from the nonlinear RS effect with high significance (50 sigma) for l(max) = 10(4) whereas forthcoming missions such as Planck and LSST are expected to yield 4 l p 10 1.5 sigma detections, on the assumption of that the point-source contributions are negligible. We find that the CMB-WL correlation has a characteristic scale which is sensitive to the nature of dark energy.Alfred P. Sloan FellowshipAstronom
All-order evaluation of weak measurements: --- The cases of an operator which satisfies the property ---
Some exact formulae of the expectation values and probability densities in a
weak measurement for an operator which satisfies the property are derived. These formulae include all-order effects of the unitary
evolution due to the von-Neumann interaction. These are valid not only in the
weak measurement regime but also in the strong measurement regime and tell us
the connection between these two regime. Using these formulae, arguments of the
optimization of the signal amplification and the signal to noise ratio are
developed in two typical experimental setups.Comment: 17 pages, 10 figures (v1); Fig.3 and some typos are corrected (v2);
Comments and references are added and some typos are corrected (v3
Measurement of redshift dependent cross correlation of HSC clusters and Fermi rays
The cross-correlation study of the unresolved -ray background (UGRB)
with galaxy clusters has a potential to reveal the nature of the UGRB. In this
paper, we perform a cross-correlation analysis between -ray data by the
Fermi Large Area Telescope (Fermi-LAT) and a galaxy cluster catalogue from the
Subaru Hyper Suprime-Cam (HSC) survey. The Subaru HSC cluster catalogue
provides a wide and homogeneous large-scale structure distribution out to the
high redshift at , which has not been accessible in previous
cross-correlation studies. We conduct the cross-correlation analysis not only
for clusters in the all redshift range () of the survey, but
also for subsamples of clusters divided into redshift bins, the low redshift
bin () and the high redshift bin (), to utilize
the wide redshift coverage of the cluster catalogue. We find the evidence of
the cross-correlation signals with the significance of 2.0-2.3 for all
redshift and low-redshift cluster samples. On the other hand, for high-redshift
clusters, we find the signal with weaker significance level (1.6-1.9).
We also compare the observed cross-correlation functions with predictions of a
theoretical model in which the UGRB originates from -ray emitters such
as blazars, star-forming galaxies and radio galaxies. We find that the detected
signal is consistent with the model prediction.Comment: 11 pages, 24 figures, accepted by MNRA
- …