新河外WMAP点源（NEWPS）星表中河外源的统计性质
Statistical properties of extragalactic sources in the New Extragalactic WMAP Point Source (NEWPS) catalogue
摘要：
我们给出了NEWPS 5样本中河外点源的光谱指数分布、数计数、红移分布和其他一般统计特性的结果。López-Caniego et al.（2007）。在所有的WMAP通道的通量校准已重新评估与地面观测的比较，并通过估计的有效光束面积。这两种方法产生一致的统计校正因子。对NED的搜索已经在23 GHz处S/N>5和S>1.1 Jy的252个源的完整子样本中产生了89%的源的光学识别; 5个源被证明是银河系的，并被删除。NED还得到了92%的河外源在|b| > 10度的红移。他们的分布与模型预测进行了比较，协议一般是好的，但注意到可能的差异。利用GB 6或PMN巡天的5GHz通量，我们发现S_23GHz> 1.3，Jy的191个河外源中有76%可以归类为5 ~ 23 GHz的平谱源。在更高的频率下观察到光谱变陡：在23和61 GHz之间，只有59%的源仍然是平谱源，平均光谱指数从<α_5^23>= 0.01 \pm 0.03变陡到<α_41^61>= 0.37 \pm 0.03。然而，我们认为，这种差异可能是由于选择效应。源数计数具有接近欧几里德的斜率，并且与De Zotti等人（2005）的宇宙演化模型的预测非常一致。观测到的光谱指数分布被利用，以获得独立于模型的外推计数到更高的频率。这种行动的风险进行了讨论，并澄清了与其他最近的估计差异的原因。
英文摘要：
We present results on spectral index distributions, number counts, redshift distribution and other general statistical properties of extragalactic point sources in the NEWPS5 sample López-Caniego et al. (2007). The flux calibrations at all the WMAP channels have been reassessed both by comparison with ground based observations and through estimates of the effective beam areas. The two methods yield consistent statistical correction factors. A search of the NED has yielded optical identifications for 89% of sources in the complete sub-sample of 252 sources with S/N>5 and S>1.1 Jy at 23 GHz; 5 sources turned out to be Galactic and were removed. The NED also yielded redshifts for 92% of the extragalactic sources at |b|>10deg. Their distribution was compared with model predictions; the agreement is generally good but a possible discrepancy is noted. Using the 5 GHz fluxes from the GB6 or PMN surveys, we find that 76% of the 191 extragalactic sources with S_23GHz>1.3,Jy can be classified as flat-spectrum sources between 5 and 23 GHz. A spectral steepening is observed at higher frequencies: only 59% of our sources are still flat-spectrum sources between 23 and 61 GHz and the average spectral indexes steepen from <alpha_5^23>= 0.01\pm 0.03 to <alpha_41^61>= 0.37\pm 0.03. We think, however, that the difference may be due to a selection effect. The source number counts have a close to Euclidean slope and are in good agreement with the predictions of the cosmological evolution model by De Zotti et al. (2005). The observed spectral index distributions were exploited to get model-independent extrapolations of counts to higher frequencies. The risks of such operations are discussed and reasons of discrepancies with other recent estimates are clarified.
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