Planck intermediate results. XV. A study of anomalous microwave emission in Galactic clouds
Abstract
Anomalous microwave emission (AME) is believed to be due to electric dipole radiation from small spinning dust grains. The aim of this paper is a statistical study of the basic properties of AME regions and the environment in which they emit. We used WMAP and Planck maps, combined with ancillary radio and IR data, to construct a sample of 98 candidate AME sources, assembling SEDs for each source using aperture photometry on 1deg-smoothed maps from 0.408 GHz up to 3000 GHz. Each spectrum is fitted with a simple model of free-free, synchrotron (where necessary), cosmic microwave background (CMB), thermal dust, and spinning dust components. We find that 42 of the 98 sources have significant (>5sigma) excess emission at frequencies between 20 and 60 GHz. An analysis of the potential contribution of optically thick free-free emission from ultra-compact HII regions, using IR colour criteria, reduces the significant AME sample to 27 regions. The spectrum of the AME is consistent with model spectra of spinning dust. The AME regions tend to be more spatially extended than regions with little or no AME. The AME intensity is strongly correlated with the submillimetre/IR flux densities and comparable to previous AME detections in the literature. AME emissivity, defined as the ratio of AME to dust optical depth, varies by an order of magnitude for the AME regions. The AME regions tend to be associated with cooler dust in the range 14-20 K and an average emissivity index of +1.8, while the non-AME regions are typically warmer, at 20-27 K. In agreement with previous studies, the AME emissivity appears to decrease with increasing column density. The emerging picture is that the bulk of the AME is coming from the polycyclic aromatic hydrocarbons and small dust grains from the colder neutral interstellar medium phase (Abridged).
Keywords
Cite
@article{arxiv.1309.1357,
title = {Planck intermediate results. XV. A study of anomalous microwave emission in Galactic clouds},
author = {Planck Collaboration and P. A. R. Ade and N. Aghanim and M. I. R. Alves and M. Arnaud and F. Atrio-Barandela and J. Aumont and C. Baccigalupi and A. J. Banday and R. B. Barreiro and E. Battaner and K. Benabed and A. Benoit-Lévy and J. -P. Bernard and M. Bersanelli and P. Bielewicz and J. Bobin and A. Bonaldi and J. R. Bond and J. Borrill and F. R. Bouchet and F. Boulanger and C. Burigana and J. -F. Cardoso and S. Casassus and A. Catalano and A. Chamballu and X. Chen and H. C. Chiang and L. -Y Chiang and P. R. Christensen and D. L. Clements and S. Colombi and L. P. L. Colombo and F. Couchot and B. P. Crill and F. Cuttaia and L. Danese and R. D. Davies and R. J. Davis and P. de Bernardis and A. de Rosa and G. de Zotti and J. Delabrouille and F. -X. Désert and C. Dickinson and J. M. Diego and S. Donzelli and O. Doré and X. Dupac and T. A. Enßlin and H. K. Eriksen and F. Finelli and O. Forni and E. Franceschi and S. Galeotta and K. Ganga and R. T. Génova-Santos and T. Ghosh and M. Giard and J. González-Nuevo and K. M. Górski and A. Gregorio and A. Gruppuso and F. K. Hansen and D. Harrison and G. Helou and C. Hernández-Monteagudo and S. R. Hildebrandt and E. Hivon and A. Hornstrup and A. H. Jaffe and T. R. Jaffe and W. C. Jones and E. Keihänen and R. Keskitalo and R. Kneissl and J. Knoche and M. Kunz and H. Kurki-Suonio and A. Lähteenmäki and J. -M. Lamarre and A. Lasenby and C. R. Lawrence and R. Leonardi and M. Liguori and P. B. Lilje and M. Linden-Vørnle and M. López-Caniego and J. F. Macías-Pérez and B. Maffei and D. Maino and N. Mandolesi and D. J. Marshall and P. G. Martin and E. Martínez-González and S. Masi and M. Massardi and S. Matarrese and P. Mazzotta and P. R. Meinhold and A. Melchiorri and L. Mendes and A. Mennella and M. Migliaccio and M. -A. Miville-Deschênes and A. Moneti and L. Montier and G. Morgante and D. Mortlock and D. Munshi and P. Naselsky and F. Nati and P. Natoli and H. U. Nørgaard-Nielsen and F. Noviello and D. Novikov and I. Novikov and C. A. Oxborrow and L. Pagano and F. Pajot and R. Paladini and D. Paoletti and G. Patanchon and T. J. Pearson and M. Peel and O. Perdereau and F. Perrotta and F. Piacentini and M. Piat and E. Pierpaoli and D. Pietrobon and S. Plaszczynski and E. Pointecouteau and G. Polenta and N. Ponthieu and L. Popa and G. W. Pratt and S. Prunet and J. -L. Puget and J. P. Rachen and R. Rebolo and W. Reich and M. Reinecke and M. Remazeilles and C. Renault and S. Ricciardi and T. Riller and I. Ristorcelli and G. Rocha and C. Rosset and G. Roudier and J. A. Rubiño-Martín and B. Rusholme and M. Sandri and G. Savini and D. Scott and L. D. Spencer and V. Stolyarov and D. Sutton and A. -S. Suur-Uski and J. -F. Sygnet and J. A. Tauber and D. Tavagnacco and L. Terenzi and C. T. Tibbs and L. Toffolatti and M. Tomasi and M. Tristram and M. Tucci and L. Valenziano and J. Valiviita and B. Van Tent and J. Varis and P. Vielva and F. Villa and B. D. Wandelt and R. Watson and A. Wilkinson and N. Ysard and D. Yvon and A. Zacchei and A. Zonca},
journal= {arXiv preprint arXiv:1309.1357},
year = {2018}
}
Comments
Submitted on behalf of Planck Collaboration by Clive Dickinson. 30 pages, 24 figures, 3 tables Updated to match the accepted version