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

Ghosh, Tuhin and Saha, Rajib and Jain, Pankaj and Souradeep, Tarun (2009) Model independent foreground power spectrum estimation using WMAP 5-year data. Physical Review D, 79 (12). Art. No. 123011. ISSN 2470-0010. https://resolver.caltech.edu/CaltechAUTHORS:20090817-095256119

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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 foreground power close to galactic plane and underestimates it at high latitudes.


Item Type:Article
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http://dx.doi.org/10.1103/PhysRevD.79.123011DOIUNSPECIFIED
http://link.aps.org/doi/10.1103/PhysRevD.79.123011PublisherUNSPECIFIED
Additional Information:© 2009 The American Physical Society. Received 23 January 2009; published 19 June 2009. Computations were carried out on Cetus, the high performance computation facility of IUCAA. Some of the results in this paper used the HEALPIX [22] Package. We acknowledge the use of the Legacy Archive for Microwave Background Data Analysis (LAMBDA). Support for LAMBDA is provided by the NASA office of Space Science. We acknowledge the use of version 1.1 of the Planck reference sky model, prepared by the working group 2 and available at [30]. A portion of the research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. T.G. thanks the Council of Scientific Research and Industrial Research, India for financial support. PACS numbers: 98.70.Vc, 98.80.Es.
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NASAUNSPECIFIED
Council of Scientific Research and Industrial Research, IndiaUNSPECIFIED
Issue or Number:12
Record Number:CaltechAUTHORS:20090817-095256119
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20090817-095256119
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15062
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:18 Aug 2009 05:35
Last Modified:03 Oct 2019 00:54

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