Sparsity and cosmology: inverse problems in cosmic microwave background experiments

F. C. Sureau; J. Bobin; J.-L. Starck

doi:10.1117/12.2024040

26 September 2013 Sparsity and cosmology: inverse problems in cosmic microwave background experiments

F. C. Sureau, J. Bobin, J.-L. Starck

Proceedings Volume 8858, Wavelets and Sparsity XV; 885811 (2013) https://doi.org/10.1117/12.2024040
Event: SPIE Optical Engineering + Applications, 2013, San Diego, California, United States

Abstract

We propose a new method to better estimate and subtract the contribution of detected compact sources to the microwave sky. These bright compact source emissions contaminate the full-sky data over a significant fraction of the sky, and should therefore be accurately removed if a high resolution and full-sky estimate of the components is sought after. However the point source spectral variability hampers accurate blind source separation, even with state-of-the-art localized source separation techniques. In this work, we rather propose to estimate the flux of the brightest compact sources using a morphological separation approach, relying on a more sophisticated model for the background than in standard approaches. Essentially, this amounts to separate point sources with known support and shape from a background assumed sparse in the spherical harmonic domain. This approach is compared to standard local χ² minimization modeling the background as a low order polynomial on WMAP realistic simulations. If in noisy situations estimating more than a few parameter does not improve flux recovery, in the first WMAP channels the proposed method leads to lower biases (typically by factors of 2) and increased robustness.

Citation Download Citation

F. C. Sureau, J. Bobin, and J.-L. Starck "Sparsity and cosmology: inverse problems in cosmic microwave background experiments", Proc. SPIE 8858, Wavelets and Sparsity XV, 885811 (26 September 2013); https://doi.org/10.1117/12.2024040

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