We perform an analysis of the diffuse low-frequency Galactic components in the southern part of the Gould Belt system (130° ≤ l ≤ 230° and -50° ≤ b ≤ -10°). Strong ultra-violet flux coming from the Gould Belt super-association is responsible for bright diffuse foregrounds that we observe from our position inside the system and that can help us improve our knowledge of the Galactic emission. Free-free emission and anomalous microwave emission (AME) are the dominant components at low frequencies (ν < 40 GHz), while synchrotron emission is very smooth and faint. We separated diffuse free-free emission and AME from synchrotron emission and thermal dust emission by using Planck data, complemented by ancillary data, using the correlated component analysis (CCA) component-separation method and we compared our results with the results of cross-correlation of foreground templates with the frequency maps. We estimated the electron temperature Te from Hα and free-free emission using two methods (temperature-temperature plot and cross-correlation) and obtained Te ranging from 3100 to 5200K for an effective fraction of absorbing dust along the line of sight of 30% (fd = 0.3). We estimated the frequency spectrum of the diffuse AME and recovered a peak frequency (in flux density units) of 25.5 ± 1.5 GHz. We verified the reliability of this result with realistic simulations that include biases in the spectral model for the AME and in the free-free template. By combining physical models for vibrational and rotational dust emission and adding the constraints from the thermal dust spectrum from Planck and IRAS, we are able to present a good description of the AME frequency spectrum for plausible values of the local density and radiation field. Appendices are available in electronic form at http://www.aanda.org
Planck intermediate results. XII. Diffuse galactic components in the Gould Belt system / P.A.R. Ade, N. Aghanim, M.I.R. Alves, M. Arnaud, M. Ashdown, F. Atrio-Barandela, J. Aumont, C. Baccigalupi, A. Balbi, A.J. Banday, R.B. Barreiro, J.G. Bartlett, E. Battaner, L. Bedini, K. Benabed, A. Benoît, J. Bernard, M. Bersanelli, A. Bonaldi, J.R. Bond, J. Borrill, F.R. Bouchet, F. Boulanger, C. Burigana, R.C. Butler, P. Cabella, J. Cardoso, X. Chen, L. Chiang, P.R. Christensen, D.L. Clements, S. Colombi, L.P.L. Colombo, A. Coulais, F. Cuttaia, R.D. Davies, R.J. Davis, P. de Bernardis, G. de Gasperis, G. de Zotti, J. Delabrouille, C. Dickinson, J.M. Diego, G. Dobler, H. Dole, S. Donzelli, O. Doré, M. Douspis, X. Dupac, T.A. Enßlin, F. Finelli, O. Forni, M. Frailis, E. Franceschi, S. Galeotta, K. Ganga, R.T. Génova-Santos, T. Ghosh, M. Giard, G. Giardino, Y. Giraud-Héraud, J. González-Nuevo, K.M. Górski, A. Gregorio, A. Gruppuso, F.K. Hansen, D. Harrison, C. Hernández-Monteagudo, S.R. Hildebrandt, E. Hivon, M. Hobson, W.A. Holmes, A. Hornstrup, W. Hovest, K.M. Huffenberger, T.R. Jaffe, A.H. Jaffe, M. Juvela, E. Keihänen, R. Keskitalo, T.S. Kisner, J. Knoche, M. Kunz, H. Kurki-Suonio, G. Lagache, A. Lähteenmäki, J. Lamarre, A. Lasenby, C.R. Lawrence, S. Leach, R. Leonardi, P.B. Lilje, M. Linden-Vørnle, P.M. Lubin, J.F. Macías-Pérez, B. Maffei, D. Maino, N. Mandolesi, M. Maris, D.J. Marshall, P.G. Martin, E. Martínez-González, S. Masi, M. Massardi, S. Matarrese, P. Mazzotta, A. Melchiorri, A. Mennella, S. Mitra, M. Miville-Deschênes, A. Moneti, L. Montier, G. Morgante, D. Mortlock, D. Munshi, J.A. Murphy, P. Naselsky, F. Nati, P. Natoli, H.U. Nørgaard-Nielsen, F. Noviello, D. Novikov, I. Novikov, S. Osborne, C.A. Oxborrow, F. Pajot, R. Paladini, D. Paoletti, M. Peel, L. Perotto, F. Perrotta, F. Piacentini, M. Piat, E. Pierpaoli, D. Pietrobon, S. Plaszczynski, E. Pointecouteau, G. Polenta, L. Popa, T. Poutanen, G.W. Pratt, S. Prunet, J. Puget, J.P. Rachen, W.T. Reach, R. Rebolo, M. Reinecke, C. Renault, S. Ricciardi, I. Ristorcelli, G. Rocha, C. Rosset, J.A. Rubiño-Martín, B. Rusholme, E. Salerno, M. Sandri, G. Savini, D. Scott, L. Spencer, V. Stolyarov, R. Sudiwala, A. Suur-Uski, J. Sygnet, J.A. Tauber, L. Terenzi, C.T. Tibbs, L. Toffolatti, M. Tomasi, M. Tristram, L. Valenziano, B. Van Tent, J. Varis, P. Vielva, F. Villa, N. Vittorio, L.A. Wade, B.D. Wandelt, N. Ysard, D. Yvon, A. Zacchei, A. Zonca. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - 557(2013 Sep), pp. A53.1-A53.20.
Planck intermediate results. XII. Diffuse galactic components in the Gould Belt system
M. Bersanelli;L.P.L. Colombo;S. Donzelli;D. Maino;A. Mennella;M. Tomasi;A. ZoncaUltimo
2013
Abstract
We perform an analysis of the diffuse low-frequency Galactic components in the southern part of the Gould Belt system (130° ≤ l ≤ 230° and -50° ≤ b ≤ -10°). Strong ultra-violet flux coming from the Gould Belt super-association is responsible for bright diffuse foregrounds that we observe from our position inside the system and that can help us improve our knowledge of the Galactic emission. Free-free emission and anomalous microwave emission (AME) are the dominant components at low frequencies (ν < 40 GHz), while synchrotron emission is very smooth and faint. We separated diffuse free-free emission and AME from synchrotron emission and thermal dust emission by using Planck data, complemented by ancillary data, using the correlated component analysis (CCA) component-separation method and we compared our results with the results of cross-correlation of foreground templates with the frequency maps. We estimated the electron temperature Te from Hα and free-free emission using two methods (temperature-temperature plot and cross-correlation) and obtained Te ranging from 3100 to 5200K for an effective fraction of absorbing dust along the line of sight of 30% (fd = 0.3). We estimated the frequency spectrum of the diffuse AME and recovered a peak frequency (in flux density units) of 25.5 ± 1.5 GHz. We verified the reliability of this result with realistic simulations that include biases in the spectral model for the AME and in the free-free template. By combining physical models for vibrational and rotational dust emission and adding the constraints from the thermal dust spectrum from Planck and IRAS, we are able to present a good description of the AME frequency spectrum for plausible values of the local density and radiation field. Appendices are available in electronic form at http://www.aanda.org
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