ARCADE 2 Observations of Galactic Radio Emission

We use absolutely calibrated data from the ARCADE 2 flight in 2006 July to model Galactic emission at frequencies 3, 8, and 10 GHz. The spatial structure in the data is consistent with a superposition of free-free and synchrotron emission. Emission with spatial morphology traced by the Haslam 408 MH...

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Bibliographic Details
Published in:The Astrophysical journal 2011-06, Vol.734 (1), p.4-jQuery1323907503786='48'
Main Authors: Kogut, A, Fixsen, D. J, Levin, S. M, Limon, M, Lubin, P. M, Mirel, P, Seiffert, M, Singal, J, Villela, T, Wollack, E, Wuensche, C. A
Format: Article
Language:English
Subjects:
Astronomy
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
DUSTS
Earth, ocean, space
ELECTROMAGNETIC RADIATION
EMISSION
Exact sciences and technology
GALAXIES
RADIATIONS
RADIOWAVE RADIATION
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Summary:We use absolutely calibrated data from the ARCADE 2 flight in 2006 July to model Galactic emission at frequencies 3, 8, and 10 GHz. The spatial structure in the data is consistent with a superposition of free-free and synchrotron emission. Emission with spatial morphology traced by the Haslam 408 MHz survey has spectral index Delta *bsynch = --2.5 ? 0.1, with free-free emission contributing 0.10 ? 0.01 of the total Galactic plane emission in the lowest ARCADE 2 band at 3.15 GHz. We estimate the total Galactic emission toward the polar caps using either a simple plane-parallel model with csc |b| dependence or a model of high-latitude radio emission traced by the COBE/FIRAS map of C II emission. Both methods are consistent with a single power law over the frequency range 22 MHz to 10 GHz, with total Galactic emission toward the north polar cap T Gal = 10.12 ? 0.90 K and spectral index Delta *b = --2.55 ? 0.03 at reference frequency 0.31 GHz. Emission associated with the plane-parallel structure accounts for only 30% of the observed high-latitude sky temperature, with the residual in either a Galactic halo or an isotropic extragalactic background. The well-calibrated ARCADE 2 maps provide a new test for spinning dust emission, based on the integrated intensity of emission from the Galactic plane instead of cross-correlations with the thermal dust spatial morphology. The Galactic plane intensity measured by ARCADE 2 is fainter than predicted by models without spinning dust and is consistent with spinning dust contributing 0.4 ? 0.1 of the Galactic plane emission at 23 GHz.
ISSN:0004-637X
1538-4357
DOI:10.1088/0004-637X/734/1/4