English
Related papers

Related papers: "Sample Variance" in Small-Scale CMB Anisotropy Ex…

200 papers

Cosmic microwave background (CMB) temperature anisotropies encode the history of the universe, which manifest itself in the angular power spectrum. We test the angular power spectra of small patches from the ESA $\textit{Planck}$ data.…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-04 Ming-Feng Ho , Lung-Yih Chiang

We present two novel methods for the estimation of the angular power spectrum of cosmic microwave background (CMB) anisotropies. We assume an absolute CMB experiment with arbitrary asymmetric beams and arbitrary sky coverage. The methods…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-25 Elina Keihänen , Kimmo Kiiveri , Hannu Kurki-Suonio , Martin Reinecke

We present results from the QMAP balloon experiment, which maps the Cosmic Microwave Background (CMB) and probes its angular power spectrum on degree scales. In two separate flights, data were taken in six channels at two frequency bands…

We study the Cosmic Microwave Background (CMB) anisotropies produced by cosine-type quintessence models. In our analysis, effects of the adiabatic and isocurvature fluctuations are both taken into account. For purely adiabatic fluctuations…

Astrophysics · Physics 2007-05-23 Tomo Takahashi

We have observed the cosmic microwave background (CMB) in three regions of sky using the Very Small Array (VSA) in an extended configuration with antennas of beamwidth 2 degrees at 34 GHz. Combined with data from previous VSA observations…

WMAP observations have accurately determined the position of the first two peaks and dips in the CMB temperature power spectrum. These encode information on the ratio of the distance to the last scattering surface to the sound horizon at…

Astrophysics · Physics 2008-11-26 Pier Stefano Corasaniti , Alessandro Melchiorri

Observations of the microwave sky using the Python telescope in its fifth season of operation at the Amundsen-Scott South Pole Station in Antarctica are presented. The system consists of a 0.75 m off-axis telescope instrumented with a HEMT…

Astrophysics · Physics 2007-05-23 Kimberly Ann Coble

We investigate the hemispherical power asymmetry in the cosmic microwave background on small angular scales. We find an anomalously high asymmetry in the multipole range l=601-2048, with a naive statistical significance of 6.5 sigma.…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-30 Samuel Flender , Shaun Hotchkiss

We are now beginning to learn detailed information about cosmological parameters from the shapes of the matter and radiation power spectra, together with their relative normalization. As more high quality data are gathered from galaxy…

Astrophysics · Physics 2007-05-23 Douglas Scott

We devise a measure n(r) to quantify a robust feature in the coherent cosmic perturbations, namely the narrowness of the first peak in the power spectrum of the Cosmic Microwave Background (CMB) anisotropy. A maximum-likelihood analysis…

Astrophysics · Physics 2007-05-23 Jiun-Huei Proty Wu

A large fraction of the information collected by cosmological surveys is simply discarded to avoid lengthscales which are difficult to model theoretically. We introduce a new technique which enables the extraction of useful information from…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-08 Fergus Simpson , J. Berian James , Alan F. Heavens , Catherine Heymans

The power spectrum of fluctuations in the cosmic microwave background (CMB) depends on most of the key cosmological parameters. Accurate future measurements of this power spectrum might therefore allow us to determine h, Omega, Omega_b,…

Astrophysics · Physics 2007-05-23 Max Tegmark

Accurate mock catalogues are essential for assessing systematics in the cosmological analysis of large galaxy surveys. Anisotropic two-point clustering measurements from the same simulation show some scatter for different lines of sight…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-07 Alex Smith , Arnaud de Mattia , Etienne Burtin , Chia-Hsun Chuang , Cheng Zhao

The Cosmological Principle states that the Universe is statistically isotropic and homogeneous on large scales. In particular, this implies statistical isotropy in the galaxy distribution, after removal of a dipole anisotropy due to the…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-16 Carlos A. P. Bengaly , Roy Maartens , Nandrianina Randriamiarinarivo , Albert Baloyi

Every experiment is affected by systematic effects that hamper the data analysis and have the potential to ultimately degrade its performance. In the case of probes of the cosmic microwave background (CMB) radiation, a minimal set of issues…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-08 Franz Elsner , Benjamin D. Wandelt

In the near future, observations of the cosmic microwave background (CMB) anisotropies will provide accurate determinations of many fundamental cosmological parameters. In this paper, we analyse degeneracies among cosmological parameters to…

Astrophysics · Physics 2009-10-30 G. Efstathiou , J. R. Bond

We present an analytic approach to the estimation of beam asymmetry effects in CMB temperature and linear polarization anisotropy experiments. We derive via perturbative expansions simple and accurate results for the case of an elliptical…

Astrophysics · Physics 2009-11-06 P. Fosalba , O. Doré , F. R. Bouchet

To assess the significance and scale dependence of anomalous large scale modes in the CatWISE quasar data, we generate smoothed number density fields on the sphere and study their extreme values -- maximum, minimum, maximum antipodal…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-10 Akhil Antony , Stephen Appleby , William L Matthewson , Arman Shafieloo

Persistent evidence for a cosmic hemispherical asymmetry in the temperature field of cosmic microwave background (CMB) as observed by both WMAP as well as PLANCK increases the possibility of its cosmological origin. Presence of this signal…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-28 Suvodip Mukherjee , Pavan K. Aluri , Santanu Das , Shabbir Shaikh , Tarun Souradeep

The measurements of CMB anisotropy have opened up a window for probing the global topology of the universe on length scales comparable to and beyond the Hubble radius. For compact topologies, the two main effects on the CMB are: (1) the…

Astrophysics · Physics 2011-04-15 J. Richard Bond , Dmitri Pogosyan , Tarun Souradeep