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arXiv 0901.0562astro-ph.GA
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ARCADE 2星系射电观测

ARCADE 2 Observations of Galactic Radio Emission

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

摘要:

我们使用绝对校准的数据从ARCADE 2飞行在2006年7月模型银河系发射频率为3,8和10 GHz。数据中的空间结构与自由-自由和同步辐射的叠加一致。由Haslam 408 MHz巡天追踪到的空间形态的辐射具有光谱指数beta_synch = -2.5 +/- 0.1,自由-自由辐射占3.15 GHz最低ARCADE 2波段总银河平面辐射的0.10 +/- 0.01。我们估计总银河向极冠发射使用一个简单的平面平行模型与csc |b|的依赖或高纬度无线电发射的COBE/FIRAS的CII排放图跟踪的模型。这两种方法在22 MHz到10 GHz的频率范围内都符合单一的幂律,在参考频率1 GHz下,银河系向北极帽的总辐射T_Gal = 0.498 +/- 0.028 K,光谱指数β = -2.55 +/- 0.03。校准良好的ARCADE 2地图提供了一个新的测试旋转尘埃排放,从银河系平面的综合发射强度的基础上,而不是互相关的热尘埃的空间形态。ARCADE 2测量的银河平面强度比没有旋转尘埃的模型预测的要弱,并且与旋转尘埃在22 GHz时贡献0.4 +/- 0.1的银河平面辐射一致。

英文摘要:

We use absolutely calibrated data from the ARCADE 2 flight in July 2006 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 beta_synch = -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 CII emission. Both methods are consistent with a single power-law over the frequency range 22 MHz to 10 GHz, with total Galactic emission towards the north polar cap T_Gal = 0.498 +/- 0.028 K and spectral index beta = -2.55 +/- 0.03 at reference frequency 1 GHz. 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 22 GHz.

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