DOI

10.1088/0004-637X/734/1/6

Abstract

We use absolutely calibrated data between 3 and 90 GHz from the 2006 balloon flight of the ARCADE 2 instrument, along with previous measurements at other frequencies, to constrain models of extragalactic emission. Such emission is a combination of the cosmic microwave background (CMB) monopole, Galactic foreground emission, the integrated contribution of radio emission from external galaxies, any spectral distortions present in the CMB, and any other extragalactic source. After removal of estimates of foreground emission from our own Galaxy, and an estimated contribution of external galaxies, we present fits to a combination of the flat-spectrum CMB and potential spectral distortions in the CMB.We find 2σ upper limits to CMB spectral distortions ofμ < 6×10−4 and |Yff| < 1×10−4. We also find a significant detection of a residual signal beyond that, which can be explained by the CMB plus the integrated radio emission from galaxies estimated from existing surveys. This residual signal may be due to an underestimated galactic foreground contribution, an unaccounted for contribution of a background of radio sources, or some combination of both. The residual signal is consistent with emission in the form of a power law with amplitude 18.4 ± 2.1 K at 0.31 GHz and a spectral index of −2.57 ± 0.05.

Document Type

Article

Publication Date

6-10-2011

Publisher Statement

Copyright © 2011. The American Astronomical Society. This article first appeared in The Astrophysical Journal 734, no. 1 (June 10, 2011): 6. doi:10.1088/0004-637X/734/1/6.

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