Data di Pubblicazione:
2013
Abstract:
Using precise full-sky observations from Planck, and applying several
methods of component separation, we identify and characterise 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 | ~ 35-50� in Galactic
latitude and | l | ~ 15-20� in longitude. By combining the Planck
data with observations from the Wilkinson Microwave Anisotropy Probe, we
were able to determine the spectrum of this emission to high accuracy,
unhindered by the strong systematic biases present in previous analyses.
The derived spectrum is consistent with power-law emission with a
spectral index of -2.56 � 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�,
the microwave haze morphology is consistent with that of the Fermi
gamma-ray "haze" or "bubbles", while at b ~ -50� we have identified
an edge in the microwave haze that is spatially coincident with the edge
in the gamma-ray bubbles. Taken together, this indicates 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 astrophysical mechanism for cosmic-ray
acceleration in the inner Galaxy is implied.
methods of component separation, we identify and characterise 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 | ~ 35-50� in Galactic
latitude and | l | ~ 15-20� in longitude. By combining the Planck
data with observations from the Wilkinson Microwave Anisotropy Probe, we
were able to determine the spectrum of this emission to high accuracy,
unhindered by the strong systematic biases present in previous analyses.
The derived spectrum is consistent with power-law emission with a
spectral index of -2.56 � 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�,
the microwave haze morphology is consistent with that of the Fermi
gamma-ray "haze" or "bubbles", while at b ~ -50� we have identified
an edge in the microwave haze that is spatially coincident with the edge
in the gamma-ray bubbles. Taken together, this indicates 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 astrophysical mechanism for cosmic-ray
acceleration in the inner Galaxy is implied.
Tipologia CRIS:
1.1 Articolo in rivista
Keywords:
Galaxy: nucleus; ISM: structure; ISM: bubbles; radio continuum: ISM
Elenco autori:
P., Collaboration; P. A., R.; N., Aghanim; M., Arnaud; M., Ashdown; F., Atrio Barandela; J., Aumont; C., Baccigalupi; A., Balbi; A. J., Banday; R. B., Barreiro; J. G., Bartlett; E., Battaner; K., Benabed; A., Beno�t; J., Bernard; M., Bersanelli; A., Bonaldi; J. R., Bond; J., Borrill; F. R., Bouchet; C., Burigana; P., Cabella; J., Cardoso; A., Catalano; L., Cay�n; R., Chary; L., Chiang; P. R., Christensen; D. L., Clements; L. P., L.; A., Coulais; B. P., Crill; F., Cuttaia; L., Danese; O., D'Arcangelo; R. J., Davis; P. d., Bernardis; G. d., Gasperis; A. d., Rosa; G. d., Zotti; J., Delabrouille; C., Dickinson; J. M., Diego; G., Dobler; H., Dole; S., Donzelli; O., Dor�; U., D�rl; M., Douspis; X., Dupac; G., Efstathiou; T. A., En�lin; H. K., Eriksen; F., Finelli; O., Forni; M., Frailis; E., Franceschi; S., Galeotta; K., Ganga; M., Giard; G., Giardino; J., Gonz�lez Nuevo; K. M., G�rski; S., Gratton; A., Gregorio; A., Gruppuso; F. K., Hansen; D., Harrison; G., Helou; S., Henrot Versill�; C., Hern�ndez Monteagudo; S. R., Hildebrandt; E., Hivon; M., Hobson; W. A., Holmes; A., Hornstrup; W., Hovest; K. M., Huffenberger; T. R., Jaffe; T., Jagemann; J., Jewell; W. C., Jones; M., Juvela; E., Keih�nen; J., Knoche; L., Knox; M., Kunz; H., Kurki Suonio; G., Lagache; A., L�hteenm�ki; J., Lamarre; A., Lasenby; C. R., Lawrence; S., Leach; R., Leonardi; P. B., Lilje; M., Linden V�rnle; M., L�pez Caniego; P. M., Lubin; J. F., Mac�as P�rez; B., Maffei; D., Maino; N., Mandolesi; M., Maris; D. J., Marshall; P. G., Martin; E., Mart�nez Gonz�lez; S., Masi; M., Massardi; S., Matarrese; F., Matthai; P., Mazzotta; P. R., Meinhold; A., Melchiorri; L., Mendes; A., Mennella; S., Mitra; A., Moneti; L., Montier; G., Morgante; D., Munshi; J. A., Murphy; P., Naselsky; P., Natoli; H. U., N�rgaard Nielsen; F., Noviello; D., Novikov; I., Novikov; S., Osborne; F., Pajot; R., Paladini; D., Paoletti; B., Partridge; T. J., Pearson; O., Perdereau; F., Perrotta; F., Piacentini; M., Piat; E., Pierpaoli; D., Pietrobon; S., Plaszczynski; E., Pointecouteau; G., Polenta; N., Ponthieu; L., Popa; T., Poutanen; G. W., Pratt; S., Prunet; J., Puget; J. P., Rachen; R., Rebolo; M., Reinecke; C., Renault; S., Ricciardi; T., Riller; I., Ristorcelli; G., Rocha; C., Rosset; Mart�n, J. A. Rubi�o.; B., Rusholme; M., Sandri; G., Savini; B. M., Schaefer; D., Scott; G. F., Smoot; L., Spencer; F., Stivoli; R., Sudiwala; A., Suur Uski; J., Sygnet; J. A., Tauber; Terenzi, Luca; L., Toffolatti; M., Tomasi; M., Tristram; M., T�rler; G., Umana; L., Valenziano; B. V., Tent; P., Vielva; F., Villa; N., Vittorio; L. A., Wade; B. D., Wandelt; M., White; D., Yvon; A., Zacchei; A., Zonca
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