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The statistical properties of a map of the primary fluctuations in the cosmic microwave background (CMB) may be specified to high accuracy by a few thousand power spectra measurements, provided the fluctuations are gaussian, yet the number…

Astrophysics · Physics 2009-11-07 Sujata Gupta , Alan F. Heavens

The "Cold Spot" in the CMB sky could be due to the presence of an anomalous huge spherical underdense region - a "Void" - of a few hundreds Mpc/h radius. Such a structure would have an impact on the CMB two-point (power spectrum) and…

Cosmology and Nongalactic Astrophysics · Physics 2010-07-02 Isabella Masina , Alessio Notari

Detailed measurements of the CMB lensing signal are an important scientific goal of ongoing ground-based CMB polarization experiments, which are mapping the CMB at high resolution over small patches of the sky. In this work we simulate CMB…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-30 Ruth Pearson , Blake Sherwin , Antony Lewis

Failure to accurately measure the outcomes of an experiment can lead to bias and incorrect conclusions. Online controlled experiments (aka AB tests) are increasingly being used to make decisions to improve websites as well as mobile and…

Other Computer Science · Computer Science 2019-04-01 Jayant Gupchup , Yasaman Hosseinkashi , Pavel Dmitriev , Daniel Schneider , Ross Cutler , Andrei Jefremov , Martin Ellis

We use statistical inference theory to explore the constraints from future galaxy weak lensing (cosmic shear) surveys combined with the current CMB constraints on cosmological parameters, focusing particularly on the running of the spectral…

Astrophysics · Physics 2009-11-10 Mustapha Ishak , Christopher M. Hirata , Patrick McDonald , Uros Seljak

We study the ellipticity of contour lines in the sky maps of the cosmic microwave background (CMB) as well as other measures of elongation. The sensitivity of the elongation on the resolution of the CMB maps which depends on the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Ralf Aurich , Holger S. Janzer , Sven Lustig , Frank Steiner

The atmosphere is one of the most important contamination sources in the ground-based Cosmic Microwave Background (CMB) observations. In this paper, we study three kinds of filters, which are polynomial filter, high-pass filter, and Wiener…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-26 Yi-Wen Wu , SiYu Li , Yang Liu , Zirui Zhang , Hao Liu , Hong Li

Certain anomalies in the CMB bring out a tension between the six-parameter flat $\Lambda$CDM model and the CMB data. We revisit the PLANCK analysis with loop quantum cosmology (LQC) predictions and show that LQC alleviates both the…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-05 Abhay Ashtekar , Brajesh Gupt , Donghui Jeong , V. Sreenath

The quality of CMB observations has improved dramatically in the last few years, and will continue to do so in the coming decade. Over a wide range of angular scales, the uncertainty due to instrumental noise is now small compared to the…

Beam asymmetries result in statistically-anisotropic cosmic microwave background (CMB) maps. Typically, they are studied for their effects on the CMB power spectrum, however they more closely mimic anisotropic effects such as gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2010-10-05 Duncan Hanson , Antony Lewis , Anthony Challinor

We propose and implement a fast, universally applicable method for extracting the angular power spectrum C_l from CMB temperature maps by first estimating the correlation function \xi(\theta). Our procedure recovers the C_l's using N^2 (but…

Weak lensing of galaxies by large scale structure can potentially measure cosmological quantities as accurately as the cosmic microwave background (CMB). However, the relation between observables and fundamental parameters is more complex…

Astrophysics · Physics 2009-10-31 Wayne Hu , Max Tegmark

We perform an independent foreground analysis of the WMAP maps to produce a cleaned CMB map (available online) useful for cross-correlation with, e.g., galaxy and X-ray maps. We use a variant of the Tegmark & Efstathiou (1996) technique…

Astrophysics · Physics 2009-10-07 Max Tegmark , Angelica de Oliveira-Costa , Andrew Hamilton

A crucial problem for partial sky analysis of CMB polarization is the $E$-$B$ leakage problem. Such leakage arises from the presence of `ambiguous' modes that satisfy properties of both $E$ and $B$ modes. Solving this problem is critical…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-03 Shamik Ghosh , Jacques Delabrouille , Wen Zhao , Larissa Santos

We investigate the E/B decomposition of CMB polarization on a masked sky. In real space, operators of E and B mode decomposition involve only differentials of CMB polarization. We may, therefore in principle, perform a clean E/B…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-10 Jaiseung Kim

Imputation of missing data in large regions of satellite imagery is necessary when the acquired image has been damaged by shadows due to clouds, or information gaps produced by sensor failure. The general approach for imputation of missing…

Applications · Statistics 2010-06-23 Valeria Rulloni , Oscar Bustos , Ana Georgina Flesia

Any isotropy violating phenomena on cosmic microwave background (CMB) induces off-diagonal correlations in the two-point function. These correlations themselves can be used to estimate the underlying anisotropic signals. Masking due to…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-09 Pavan K. Aluri , Nidhi Pant , Aditya Rotti , Tarun Souradeep

We present a method of subtracting the foreground contamination for the measurement of CMB polarization. We calculate the resultant errors on CMB polarization and temperature-polarization cross correlation power spectra for the high…

Astrophysics · Physics 2007-05-23 Simon Prunet , Shiv K. Sethi , Francois R. Bouchet

The observed hemispherical asymmetry in CMB map can be explained by modulation from a long wavelength super horizon mode which non-linearly couples to the CMB modes. We address the criticism in [1] about the role of non-Gaussianities in…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Mohammad Hossein Namjoo , Ali Akbar Abolhasani , Shant Baghram , Hassan Firouzjahi

In addition to its spectrum and temperature anisotropy, the 2.7K Cosmic Microwave Background is also expected to exhibit a low level of polarization. The spatial power spectrum of the polarization can provide details about the formation of…

Astrophysics · Physics 2009-10-30 Brian Keating , Peter Timbie , Alexander Polnarev , Julia Steinberger