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Title: Model independent foreground power spectrum estimation using WMAP 5-year data

Abstract

In this paper, we propose and implement on WMAP 5 yr data a model independent approach of foreground power spectrum estimation for multifrequency observations of the CMB experiments. Recently, a model independent approach of CMB power spectrum estimation was proposed by Saha et al. 2006. This methodology demonstrates that the CMB power spectrum can be reliably estimated solely from WMAP data without assuming any template models for the foreground components. In the current paper, we extend this work to estimate the galactic foreground power spectrum using the WMAP 5 yr maps following a self-contained analysis. We apply the model independent method in harmonic basis to estimate the foreground power spectrum and frequency dependence of combined foregrounds. We also study the behavior of synchrotron spectral index variation over different regions of the sky. We use the full sky Haslam map as an external template to increase the degrees of freedom, while computing the synchrotron spectral index over the frequency range from 408 MHz to 94 GHz. We compare our results with those obtained from maximum entropy method foreground maps, which are formed in pixel space. We find that relative to our model independent estimates maximum entropy method maps overestimate the foregroundmore » power close to galactic plane and underestimates it at high latitudes.« less

Authors:
;  [1];  [1];  [2]
  1. IUCAA, Post Bag 4, Ganeshkhind, Pune-411007 (India)
  2. Department of Physics, Indian Institute of Technology, Kanpur, U.P, 208016 (India)
Publication Date:
OSTI Identifier:
21300929
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles Fields
Additional Journal Information:
Journal Volume: 79; Journal Issue: 12; Other Information: DOI: 10.1103/PhysRevD.79.123011; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0556-2821
Country of Publication:
United States
Language:
English
Subject:
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; CALCULATION METHODS; COMPARATIVE EVALUATIONS; DEGREES OF FREEDOM; ENTROPY; FREQUENCY DEPENDENCE; GHZ RANGE; MHZ RANGE; RELICT RADIATION; SIMULATION; SPACE; SPECTRA; SYNCHROTRONS; VARIATIONS

Citation Formats

Ghosh, Tuhin, Souradeep, Tarun, Saha, Rajib, Jet Propulsion Laboratory, M/S 169-327, 4800 Oak Grove Drive, Pasadena, California 91109, California Institute of Technology, Pasadena, California 91125, Department of Physics, Indian Institute of Technology, Kanpur, U.P, 208016, and Jain, Pankaj. Model independent foreground power spectrum estimation using WMAP 5-year data. United States: N. p., 2009. Web. doi:10.1103/PHYSREVD.79.123011.
Ghosh, Tuhin, Souradeep, Tarun, Saha, Rajib, Jet Propulsion Laboratory, M/S 169-327, 4800 Oak Grove Drive, Pasadena, California 91109, California Institute of Technology, Pasadena, California 91125, Department of Physics, Indian Institute of Technology, Kanpur, U.P, 208016, & Jain, Pankaj. Model independent foreground power spectrum estimation using WMAP 5-year data. United States. https://doi.org/10.1103/PHYSREVD.79.123011
Ghosh, Tuhin, Souradeep, Tarun, Saha, Rajib, Jet Propulsion Laboratory, M/S 169-327, 4800 Oak Grove Drive, Pasadena, California 91109, California Institute of Technology, Pasadena, California 91125, Department of Physics, Indian Institute of Technology, Kanpur, U.P, 208016, and Jain, Pankaj. 2009. "Model independent foreground power spectrum estimation using WMAP 5-year data". United States. https://doi.org/10.1103/PHYSREVD.79.123011.
@article{osti_21300929,
title = {Model independent foreground power spectrum estimation using WMAP 5-year data},
author = {Ghosh, Tuhin and Souradeep, Tarun and Saha, Rajib and Jet Propulsion Laboratory, M/S 169-327, 4800 Oak Grove Drive, Pasadena, California 91109 and California Institute of Technology, Pasadena, California 91125 and Department of Physics, Indian Institute of Technology, Kanpur, U.P, 208016 and Jain, Pankaj},
abstractNote = {In this paper, we propose and implement on WMAP 5 yr data a model independent approach of foreground power spectrum estimation for multifrequency observations of the CMB experiments. Recently, a model independent approach of CMB power spectrum estimation was proposed by Saha et al. 2006. This methodology demonstrates that the CMB power spectrum can be reliably estimated solely from WMAP data without assuming any template models for the foreground components. In the current paper, we extend this work to estimate the galactic foreground power spectrum using the WMAP 5 yr maps following a self-contained analysis. We apply the model independent method in harmonic basis to estimate the foreground power spectrum and frequency dependence of combined foregrounds. We also study the behavior of synchrotron spectral index variation over different regions of the sky. We use the full sky Haslam map as an external template to increase the degrees of freedom, while computing the synchrotron spectral index over the frequency range from 408 MHz to 94 GHz. We compare our results with those obtained from maximum entropy method foreground maps, which are formed in pixel space. We find that relative to our model independent estimates maximum entropy method maps overestimate the foreground power close to galactic plane and underestimates it at high latitudes.},
doi = {10.1103/PHYSREVD.79.123011},
url = {https://www.osti.gov/biblio/21300929}, journal = {Physical Review. D, Particles Fields},
issn = {0556-2821},
number = 12,
volume = 79,
place = {United States},
year = {Mon Jun 15 00:00:00 EDT 2009},
month = {Mon Jun 15 00:00:00 EDT 2009}
}