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P. D. Naselsky

Publications and source records attributed to P. D. Naselsky.

14 recordsLinked to original sources
arXiv2012

Faraday Rotation as a diagnostic of Galactic foreground contamination of CMB maps

The contribution from the residuals of the foreground can have a significant impact on the temperature maps of the Cosmic Microwave Background (CMB). Mostly, the focus has been on the galactic plane, when foreground cleaning has taken place. However, in this paper, we will investigate the possible foreground contamination, from sources outside the galactic plane in the CMB maps. We will analyze the correlation between the Faraday rotation map and the CMB temperature map. The Faraday rotation map is dependent on the galactic magnetic field, as well as the thermal electron density, and both may contribute to the CMB temperature. We find that the standard deviation for the mean cross correlation deviate from that of simulations at the 99.9% level. Additionally, a comparison between the CMB temperature extrema and the extremum points of the Faraday rotation is also performed, showing a general overlap between the two. Also we find that the CMB Cold Spot is located at an area of strong negative cross correlation, meaning that it may be explained by a galactic origin. Further, we investigate nearby supernova remnants in the galaxy, traced by the galactic radio loops. These super nova remnants are located at high and low galactic latitude, and thus well outside the galactic plane. We find some correlation between the Faraday Rotation and the CMB temperature, at select radio loops. This indicate, that the galactic foregrounds may affect the CMB, at high galactic latitudes

astro-ph.CO↗
arXiv2007

On the Antenna Beam Shape Reconstruction Using Planet Transit

The calibration of the in-flight antenna beam shape and possible beamdegradation is one of the most crucial tasks for the upcoming Planck mission. We examine several effects which could significantly influence the in-flight main beam calibration using planet transit: the problems of the variability of the Jupiter's flux, the antenna temperature and passing of the planets through the main beam. We estimate these effects on the antenna beam shape calibration and calculate the limits on the main beam and far sidelobe measurements, using observations of Jupiter and Saturn. We also discuss possible effects of degradation of the mirror surfaces and specify corresponding parameters which can help us to determine these effects.

astro-ph↗
arXiv2005

Gauss--Legendre Sky Pixelization (GLESP) for CMB maps

A new scheme of sky pixelization is developed for CMB maps. The scheme is based on the Gauss--Legendre polynomials zeros and allows one to create strict orthogonal expansion of the map. A corresponding code has been implemented and comparison with other methods has been done.

astro-ph↗
arXiv2005

First Release of Gauss-Legendre Sky Pixelization (GLESP) software package for CMB analysis

We report the release of the Gauss--Legendre Sky Pixelization (GLESP) software package version 1.0. In this report we present the main features and functions for processing and manipulation of sky signals. Features for CMB polarization is underway and to be incorporated in a future release. Interested readers can visit http://www.glesp.nbi.dk (www.glesp.nbi.dk) and register for receiving the package.

astro-ph↗
arXiv2003

Cross-correlation of the CMB and foregrounds phases derived from the WMAP data

We present circular and linear cross-correlation tests and the "friend-of-friend" analysis for phases of the Internal Linear Combination Map (ILC) and the WMAP foregrounds for all K--W frequency bands at the range of multipoles $\ell\le100$. We compare also Tegmark, de Oliveira-Costa and Hamilton (2003) and Naselsky et al. (2003) cleaned maps with corresponding foregrounds. We have found significant deviations from the expected Poissonian statistics for all the cleaned maps and foregrounds. Our analysis shows that, for a low multipole range of the cleaned maps, power spectra contains some of the foregrounds residuals mainly from the W band.

astro-ph↗
arXiv2003

Phase cross-correlation of the WMAP ILC map and foregrounds

We present a circular cross-correlation tests for the phases of the Internal Linear Combination Map (ILC) and {\it WMAP}'s foregrounds for all K--W frequency bands at the range of multipoles $\ell\le 50$. We have found significant deviations from the expected Poissonian statistics for the ILC and the foregrounds phases. Our analysis shows that the low multipole range of the ILC power spectrum contains some of the foregrounds residues.

astro-ph↗
arXiv2002

Ionization history of the cosmic plasma in the light of the recent CBI and future PLANCK data

The paper is devoted to the methods of determination of the cosmological parameters from recent CMB observations. We show that the more complex models of kinetics of recombination with a few "missing" parameters describing the recombination process provide better agreement between measured and expected characteristics of the CMB anisotropy. In particular, we consider the external sources of the Ly-{alpha} and Ly-{c} radiation and the model with the strong clustering of baryonic component. These factors can constrain the estimates of the cosmological parameters usually discussed. We demonstrate also that the measurements of polarization can improve these estimates and, for the precision expected for the PLANCK mission, allow to discriminate a wide class of models.

astro-ph↗
arXiv2002

An adaptive filter for the PLANCK Compact Source Catalogue construction

We develop a linear algorithm for extracting extragalactic point sources for the Compact Source Catalogue of the upcoming PLANCK mission. This algorithm is based on a simple top-hat filter in the harmonic domain with an adaptive filtering range which does not require a priori knowledge of the CMB power spectrum and the experiment parameters such as the beam size and shape nor pixel noise level.

astro-ph↗
arXiv2002

Ionization history of the Universe as a test for Super Heavy Dark Matter particles

In this paper we discuss the possible distortions of the ionization history of the universe caused by an injection of non-thermal energy due to decays of hypothetical Super Heavy Dark Matter (SHDM) particles. These particles are usually considered as a possible source of Ultra High Energy Cosmic Rays (UHECRs) in the framework of the Top-Down model. Estimates of fraction of energy of decays converted to the UV range show that, for suitable parameters of SHDM particles, the significant distortions of power spectra of CMB anisotropy appear. Comparison with the observed power spectrum allows to restrict some properties of the SHDM particles. These decays can also increase of about 5 -- 10 times the degree of ionization of hydrogen at redshifts $z\sim$ 10 -- 50 that essentially accelerates the formation of molecules $H_2$ and first stars during "dark ages".

astro-ph↗
arXiv2001

Asymmetry of the PLANCK antenna beam shape and its manifestation in the CMB data

We present a new method to extract the beam shape incorporated in the pixelized map of CMB experiments. This method is based on the interplay of the amplitudes and phases of the signal and instrumental noise. By adding controlled white noise onto the map, the phases are perturbed in such a way that the beam shape manifests itself through the mean-squared value of the difference between original and perturbed phases. This method is useful in extracting preliminary antenna beam shape without time-consuming spherical harmonic computations.

astro-ph↗
arXiv2000

Ultra - High Energy Cosmic Rays from decay of the Super Heavy Dark Matter Relics

In this paper we briefly discuss the problem of the origin of Ultra High Energy Cosmic Rays in the framework of Top-Down models. We show that, for high energy of decays and in a wide range of spectra of injected protons, their extragalactic flux is consistent with the observed fluxes of cosmic rays in the energy range 0.1 E_{GZK}< E < 10E_{GZK}. For suitable energy and spectra of injected protons, the contribution of galactic sources is moderate, in this energy range, but it dominates at smaller and larger energies. In such models we can expect that at these energies the anisotropy of cosmic rays distribution over sky will be especially small. Some possible manifestations of decays of super massive particles such as, for example, primordial black holes with masses M_{pbh} ~ 10^{-5} g, are considered. In particular, we show that partial conversion of energy released during these decays at redshifts z ~ 1000 to Ly-alpha photons can delay the hydrogen recombination and distort the spectrum of fluctuations of the cosmic microwave background radiation.

astro-ph↗
arXiv1999

The Cosmological Gene Project: cluster analysis of the atmospheric fluctuations on arcmin-scale imaging of the Cosmic Microwave Background

We discuss some aspects of the Cosmological Gene Project started at the Special Astrophysical Observatory (Russia) in 1999. The goal of the project is to measure the anisotropy and polarization of the Cosmic Microwave Background (CMB) and investigation of atmospheric fluctuations and foreground on arcmin-scales using the radio-telescope RATAN-600. We develop the cluster analysis of one-dimensional random fields for the application to the RATAN-600 scans. We analyze the specific properties of peak clusterisation in the RATAN-600 scans which to separate the primordial CMB signal from noise.

astro-ph↗
arXiv1998

General Statistical properties of the CMB Polarization field

The distribution of the polarization of the Cosmic Microwave Background (CMB) in the sky is determined by the hypothesis of random Gaussian distribution of the primordial density perturbations. This hypotheses is well motivated by the inflationary cosmology. Therefore, the test of consistency of the statistical properties of the CMB polarization field with the Gaussianity of primordial density fluctuations is a realistic way to study the nature of primordial inhomogeneities in the Universe. This paper contains the theoretical predictions of the general statistical properties of the CMB polarization field. All results obtained under assumption of the Gaussian nature of the signal. We pay the special attention to the following two problems. First, the classification and statistics of the singular points of the polarization field where polarization is equal to zero. Second, the topology of contours of the value of the degree of polarization. We have investigated the percolation properties for the zones of ``strong'' and ``weak'' polarization. We also have calculated Minkowski functionals for the CMB polarization field. All results are analytical.

astro-ph↗