Interpretation of the Extragalactic Radio Background - Astrophysics > Cosmology and Nongalactic AstrophysicsReport as inadecuate




Interpretation of the Extragalactic Radio Background - Astrophysics > Cosmology and Nongalactic Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We use absolutely calibrated data between 3 and 90 GHz from the 2006 balloonflight of the ARCADE 2 instrument, along with previous measurements at otherfrequencies, to constrain models of extragalactic emission. Such emission is acombination of the Cosmic Microwave Background CMB monopole, Galacticforeground emission, the integrated contribution of radio emission fromexternal galaxies, any spectral distortions present in the CMB, and any otherextragalactic source. After removal of estimates of foreground emission fromour own Galaxy, and the estimated contribution of external galaxies, we presentfits to a combination of the flat-spectrum CMB and potential spectraldistortions in the CMB. We find 2 sigma upper limits to CMB spectraldistortions of mu < 5.8 x 10^{-5} and Y ff < 6.2 x 10^{-5}. We also find asignificant detection of a residual signal beyond that which can be explainedby the CMB plus the integrated radio emission from galaxies estimated fromexisting surveys. After subtraction of an estimate of the contribution ofdiscrete radio sources, this unexplained signal is consistent withextragalactic emission in the form of a power law with amplitude 1.06 \pm 0.11K at 1 GHz and a spectral index of -2.56 \pm 0.04.



Author: M. Seiffert, D. J. Fixsen, A. Kogut, S. M. Levin, M. Limon, P. M. Lubin, P. Mirel, J. Singal, T. Villela, E. Wollack, C. A. Wuens

Source: https://arxiv.org/







Related documents