Estimating the spectral indices of correlated astrophysical foregrounds by a second-order statistical approach
Bonaldi A., Bedini L., Salerno E., Baccigalupi C., De Zotti G.
Astrophysics Astrophysics (astro-ph) Astronomy and Astrophysics J.2 Physical sciences and engineering Blind source separation FOS: Physical sciences Space and Planetary Science
We present the first tests of a new method, the correlated component analysis (CCA) based on second-order statistics, to estimate the mixing matrix, a key ingredient to separate astrophysical foregrounds superimposed to the Cosmic Microwave Background (CMB). In the present application, the mixing matrix is parametrized in terms of the spectral indices of Galactic synchrotron and thermal dust emissions, while the free-free spectral index is prescribed by basic physics, and is thus assumed to be known. We consider simulated observations of the microwave sky with angular resolution and white stationary noise at the nominal levels for the Planck satellite, and realistic foreground emissions, with a position-dependent synchrotron spectral index. We work with two sets of Planck frequency channels: the low-frequency set, from 30 to 143 GHz, complemented with the Haslam 408 MHz map, and the high-frequency set, from 217 to 545 GHz. The concentration of intense free-free emission on the Galactic plane introduces a steep dependence of the spectral index of the global Galactic emission with Galactic latitude, close to the Galactic equator. This feature makes difficult for the CCA to recover the synchrotron spectral index in this region, given the limited angular resolution of Planck, especially at low frequencies. A cut of a narrow strip around the Galactic equator (|b| 3?), however, allows us to overcome this problem. We show that, once this strip is removed, the CCA allows an effective foreground subtraction, with residual uncertainties inducing a minor contribution to errors on the recovered CMB power spectrum.
Source: Monthly notices of the Royal Astronomical Society (Print) 373 (2006): 271–279. doi:10.1111/j.1365-2966.2006.11025.x
Publisher: Blackwell Scientific Publications, Oxford , Regno Unito
Amari S., Chichocki A., 1998, proc. IEEE 86, 2026
Baccigalupi C. et al., 2000, MNRAS, 318, 769
Baccigalupi C., Perrotta F., de Zotti G., Smoot G. F., Burigana C., Maino D., Bedini L., Salerno E., 2004, MNRAS, 354, 55
Barreiro R. B., Hobson M. P., Banday A. J., Lasenby A. N., Stolyarov V., Vielva P., Go´rski K. M., 2004, MNRAS, 351, 515
Bedini L.,Herranz D., Salerno E., Baccigalupi C., Kuruog˘lu E.E., Tonazzini A., 2005, EURASIP Journal on Applied Signal Processing, 15, 2400
Belouchrani A., Abed-Meraim K., Cardoso J.-F., Moulines E., 1997, IEEE Trans. on signal Processing, 45, 434
Bennett C. L. et al., 2003a, ApJS, 148, 1
Bennett C. L. et al., 2003b, ApJS, 148, 97
Bouchet F.R., Prunet S., Sethi S.K., 1999, MNRAS, 302,663
de Zotti G., Toffolatti L., Argu¨eso F., Davies R.D., Mazzotta P., Partridge R.B., Smoot G.F., Vittorio N., 1999, AIPC, 476, 204
Dickinson C., Davies R.D., & Davis R.J., 2003, MNRAS, 341 369
Eriksen H.K., Dickinson C., Lawrence C.R., Baccigalupi C., Banday A.J., Go´rski K.M., Hansen F.K., Lilje P.B., Pierpaoli E., Seiffert M.D., Smith K.M. & Vanderlinde K., 2006, ApJ, 641, 665
Finkbeiner D.P., Davies M., Schelegel D.J., 1999, ApJ 524, 867
Finkbeiner D.P., 2003 ApJS, 146, 407
Giardino G. et al., 2002, A&A, 387, 82
Go´rski K.M., Hivon E., Banday A.J., Wandelt B.D., Hansen F.K., Reinecke M., Bartelmann M., 2005, ApJ 622, 759
Haffner L.M., Reynolds R.J., Tufte S.L., 1999, ApJ, 523, 233
Haslam C. G. T. et al., 1982, A&A S 47,1
Hivon E., Go´rski K.M., Netterfield C.B., Crill B.P., Prunet S., & Hansen F., 2002, ApJ, 567,2
Hyva¨rinen A. 1999, IEEE Signal Processing Lett. 6, 145
Hobson M.P., Jones A.W., Lasenby A.N., Bouchet F., 1998, MNRAS, 300,1
Lamarre J. M. et al., 2003, NewAR, 47, 1017
Maino D. et al., 2002, MNRAS, 334, 53
Maino D., Banday A. J., Baccigalupi C., Perrotta F., Go´rski K. M., 2003, MNRAS, 344, 544
Maisinger K., Hobson M. P., Lasenby A. N., 2004, MNRAS, 347, 339
Mandolesi N., Morgante G., Villa F., 2003, SPIE, 4850, 722
Patanchon G., Cardoso J.-F., Delabrouille J., Vielva P., 2005, MNRAS, 364, 1185
Schlegel D.J.,Finkbeiner D.P., Davies M., 1998, ApJ 500, 525
Spergel D.N. et al., 2006, submitted to ApJS (astro-ph/0603449)
Stivoli S., Baccigalupi C., Maino D., Stompor R., 2006, submitted to MNRAS (astro-ph/0505381)
Stolyarov V., Hobson M. P., Lasenby A. N., Barreiro R. B., 2005, MNRAS, 357, 145
Tauber J.A., 2004, AdSpR, 34, 491
Tegmark M., 1996, MNRAS 280,299
Tegmark M., Efstathiou G., 1996, MNRAS 281, 1297
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@article{oai:it.cnr:prodotti:43885,
title = {Estimating the spectral indices of correlated astrophysical foregrounds by a second-order statistical approach},
author = {Bonaldi A. and Bedini L. and Salerno E. and Baccigalupi C. and De Zotti G.},
publisher = {Blackwell Scientific Publications, Oxford , Regno Unito},
doi = {10.1111/j.1365-2966.2006.11025.x and 10.48550/arxiv.astro-ph/0609701},
journal = {Monthly notices of the Royal Astronomical Society (Print)},
volume = {373},
pages = {271–279},
year = {2006}
}
0000-0002-3433-3634
