Planck Intermediate Results. IX. Detection of the Galactic haze with Planck
Abstract
Using precise full-sky observations from Planck, and applying several methods of component separation, we identify and characterize the emission from the Galactic "haze" at microwave wavelengths. The haze is a distinct component of diffuse Galactic emission, roughly centered on the Galactic centre, and extends to |b| ~35 deg in Galactic latitude and |l| ~15 deg in longitude. By combining the Planck data with observations from the WMAP we are able to determine the spectrum of this emission to high accuracy, unhindered by the large systematic biases present in previous analyses. The derived spectrum is consistent with power-law emission with a spectral index of -2.55 +/- 0.05, thus excluding free-free emission as the source and instead favouring hard-spectrum synchrotron radiation from an electron population with a spectrum (number density per energy) dN/dE ~ E^-2.1. At Galactic latitudes |b|<30 deg, the microwave haze morphology is consistent with that of the Fermi gamma-ray "haze" or "bubbles," indicating that we have a multi-wavelength view of a distinct component of our Galaxy. Given both the very hard spectrum and the extended nature of the emission, it is highly unlikely that the haze electrons result from supernova shocks in the Galactic disk. Instead, a new mechanism for cosmic-ray acceleration in the centre of our Galaxy is implied.
Keywords
Cite
@article{arxiv.1208.5483,
title = {Planck Intermediate Results. IX. Detection of the Galactic haze with Planck},
author = {Planck Collaboration and P. A. R. Ade and N. Aghanim and M. Arnaud and M. Ashdown and F. Atrio-Barandela and J. Aumont and C. Baccigalupi and A. Balbi and A. J. Banday and R. B. Barreiro and J. G. Bartlett and E. Battaner and K. Benabed and A. Benoît and J. -P. Bernard and M. Bersanelli and A. Bonaldi and J. R. Bond and J. Borrill and F. R. Bouchet and C. Burigana and P. Cabella and J. -F. Cardoso and A. Catalano and L. Cayón and R. -R. Chary and L. -Y Chiang and P. R. Christensen and D. L. Clements and L. P. L. Colombo and A. Coulais and B. P. Crill and F. Cuttaia and L. Danese and O. D'Arcangelo and R. J. Davis and P. de Bernardis and G. de Gasperis and A. de Rosa and G. de Zotti and J. Delabrouille and C. Dickinson and J. M. Diego and G. Dobler and H. Dole and S. Donzelli and O. Doré and U. Dörl and M. Douspis and X. Dupac and G. Efstathiou and T. A. Enßlin and H. K. Eriksen and F. Finelli and O. Forni and M. Frailis and E. Franceschi and S. Galeotta and K. Ganga and M. Giard and G. Giardino and J. González-Nuevo and K. M. Górski and S. Gratton and A. Gregorio and A. Gruppuso and F. K. Hansen and D. Harrison and G. Helou and S. Henrot-Versillé and C. Hernández-Monteagudo and S. R. Hildebrandt and E. Hivon and M. Hobson and W. A. Holmes and A. Hornstrup and W. Hovest and K. M. Huffenberger and T. R. Jaffe and T. Jagemann and W. C. Jones and M. Juvela and E. Keihänen and J. Knoche and L. Knox and M. Kunz and H. Kurki-Suonio and G. Lagache and A. Lähteenmäki and J. -M. Lamarre and A. Lasenby and C. R. Lawrence and S. Leach and R. Leonardi and P. B. Lilje and M. Linden-Vørnle and M. López-Caniego and P. M. Lubin and J. F. Macías-Pérez and B. Maffei and D. Maino and N. Mandolesi and M. Maris and P. G. Martin and E. Martínez-González and S. Masi and M. Massardi and S. Matarrese and F. Matthai and P. Mazzotta and P. R. Meinhold and A. Melchiorri and L. Mendes and A. Mennella and S. Mitra and M. -A. Miville-Deschênes and A. Moneti and L. Montier and G. Morgante and D. Munshi and J. A. Murphy and P. Naselsky and P. Natoli and H. U. Nørgaard-Nielsen and F. Noviello and S. Osborne and F. Pajot and R. Paladini and D. Paoletti and B. Partridge and T. J. Pearson 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 T. Poutanen and G. W. Pratt and S. Prunet and J. -L. Puget and J. P. Rachen and R. Rebolo and M. Reinecke and C. Renault and S. Ricciardi and T. Riller and G. Rocha and C. Rosset and J. A. Rubiño-Martín and B. Rusholme and M. Sandri and G. Savini and B. M. Schaefer and D. Scott and G. F. Smoot and F. Stivoli and R. Sudiwala and A. -S. Suur-Uski and J. -F. Sygnet and J. A. Tauber and L. Terenzi and L. Toffolatti and M. Tomasi and M. Tristram and M. Türler and G. Umana and L. Valenziano and B. Van Tent and P. Vielva and F. Villa and N. Vittorio and L. A. Wade and B. D. Wandelt and M. White and D. Yvon and A. Zacchei and A. Zonca},
journal= {arXiv preprint arXiv:1208.5483},
year = {2015}
}
Comments
15 pages, 9 figures, submitted to Astronomy and Astrophysics