C-Band All-Sky Survey: a first look at the Galaxy
C-Band All-Sky Survey: a first look at the Galaxy
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DOI：
10.1093/mnras/stv212
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发表时间：
2015-04-21
影响因子：
4.8
通讯作者：
Zuntz, J.
中科院分区：
文献类型：
--
作者：
Irfan, M. O.;Dickinson, C.;Zuntz, J.
我们提出了一个5 GHz的漫射发射在银河平面的第一象限使用两个月的初步强度数据与C波段全天巡天（C-BASS）北方仪器在欧文斯谷射电天文台，加州。结合C-BASS图和辅助数据绘制温度-温度图，我们发现在0.408和5 GHz之间的同步辐射光谱指数β = -2.65 +/-0.05，1.420和5 GHz之间的同步辐射光谱指数β = -2.72 +/-0.09，其中-10度<竖线B < -4度，20度< l < 40度。通过减去射电复合线自由-自由模板，我们确定在0.408和5 GHz之间银河平面（垂直条B垂直条< 4度）的同步加速器光谱指数为beta =-2.56 +/- 0.07，其中53 +/-8%来自5 GHz的自由-自由发射。这些结果与以前在银河系平面的低频测量是一致的。通过包括C-BASS数据的光谱拟合，我们证明了存在的异常微波发射（AME）与H II复合物W 43，W 44和W 47在30 GHz附近，在4.4西格玛，3.1s和2.5西格玛，分别。康沃尔语（Co-ordinated Radio 'N' Infrared Survey for High mass星星formation）VLA 5-GHz源目录排除了在30 GHz附近检测到的过量辐射可能是由于超致密HII区域的可能性。在5和22.8GHz之间，在30度<1 < 40度，-2度< B < 2度内，也在4 σ水平下识别出扩散AME。
We present an analysis of the diffuse emission at 5 GHz in the first quadrant of the Galactic plane using two months of preliminary intensity data taken with the C-Band All-Sky Survey (C-BASS) northern instrument at the Owens Valley Radio Observatory, California. Combining C-BASS maps with ancillary data to make temperature-temperature plots, we find synchrotron spectral indices of beta = -2.65 +/- 0.05 between 0.408 and 5 GHz and beta = -2.72 +/- 0.09 between 1.420 and 5 GHz for -10 degrees < vertical bar b vertical bar < -4 degrees, 20 degrees < l < 40 degrees. Through the subtraction of a radio recombination line free-free template, we determine the synchrotron spectral index in the Galactic plane (vertical bar b vertical bar< 4 degrees) to be beta =-2.56 +/- 0.07 between 0.408 and 5 GHz, with a contribution of 53 +/- 8 per cent from free-free emission at 5 GHz. These results are consistent with previous low-frequency measurements in the Galactic plane. By including C-BASS data in spectral fits, we demonstrate the presence of anomalous microwave emission (AME) associated with the H II complexes W43, W44 and W47 near 30 GHz, at 4.4 sigma, 3.1s and 2.5 sigma, respectively. The CORNISH (Co-Ordinated Radio 'N' Infrared Survey for High mass star formation) VLA 5-GHz source catalogue rules out the possibility that the excess emission detected around 30 GHz may be due to ultracompact HII regions. Diffuse AME was also identified at a 4 sigma level within 30 degrees < l < 40 degrees, -2 degrees < b < 2 degrees between 5 and 22.8 GHz.