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arXiv 0901.0559astro-ph.CO
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河外射电背景的解释

Interpretation of the Extragalactic Radio Background

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. Wuensche

摘要:

我们使用绝对校准的数据从2006年的ARCADE 2仪器的气球飞行3和90 GHz之间,以及以前的测量在其他频率,约束模型的河外发射。这种辐射是宇宙微波背景(CMB)辐射、银河前景辐射、来自外部星系的射电辐射、CMB中存在的任何光谱失真以及任何其他河外源的综合贡献的组合。去除我们自己的银河系的前景发射的估计和外部星系的估计贡献后,我们提出了适合的组合的平坦光谱CMB和潜在的光谱失真的CMB。我们发现CMB频谱失真的2 σ上限为mu < 5.8 x 10^{-5}和Y_ff < 6.2 x 10^{-5}。我们还发现了一个显着的检测超出了可以解释的CMB加上从现有的调查估计的星系的综合无线电发射的剩余信号。在减去离散射电源的贡献的估计值后,这个无法解释的信号与河外辐射一致,其形式为幂律,在1 GHz时振幅为1.06 \pm 0.11 K,光谱指数为-2.56 \pm 0.04。

英文摘要:

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 the 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 2 sigma upper limits to CMB spectral distortions of mu < 5.8 x 10^{-5} and Y_ff < 6.2 x 10^{-5}. 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. After subtraction of an estimate of the contribution of discrete radio sources, this unexplained signal is consistent with extragalactic emission in the form of a power law with amplitude 1.06 \pm 0.11 K at 1 GHz and a spectral index of -2.56 \pm 0.04.

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