Bright extragalactic radio sources at 2.7 GHz – II. Observations with the Cambridge 5-km telescope
Bright extragalactic radio sources at 2.7 GHz – II. Observations with the Cambridge 5-km telescope
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DOI：
10.1093/mnras/198.3.843
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发表时间：
1982-03
影响因子：
4.8
通讯作者：
J. Peacock;J. Wall
中科院分区：
文献类型：
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作者：
J. Peacock;J. Wall
本文介绍了用剑桥5公里射电望远镜对168个S（2.7 GHz）> 1.5 Jy的河外源的51个射电源的观测结果。测量在5或2.7 GHz的频率下进行。在这51个源中，只有9个得到了分辨;另外3个扩展最广的源也是用剑桥一英里望远镜在1400和408兆赫观测到的，由于其他117个源以前已经用5公里望远镜研究过，现在可以得到整个2.7千兆赫样品的结构信息，并可以与在低频选择的类似样品进行比较。在2.7-GHz样本中，大量未分辨的源并不像通常认为的那样都是平谱天体;不少于44%的源具有陡峭的高频谱，其中1.05是陡峭的。这些无法分辨的陡谱天体既不能被归类为扩展射电源，也不能被归类为“厘米过剩”的紧凑天体;它们形成了自己独特的一类。然而，有证据表明，它可能是有用的，同时考虑紧凑和扩展陡谱源作为一个单一的人口。
This paper presents observations with the Cambridge 5-km telescope of 51 radio sources taken from a complete sample of 168 extragalactic sources havingS(2.7 GHz) > 1.5 Jy. The measurements were made at a frequency of either 5 or 2.7 GHz. Of these 51 sources, only nine were resolved; the three most extended sources were also observed at 1400 and 408 MHz with the Cambridge One-Mile telescope.Since the other 117 sources have been studied previously with the 5-km telescope, structural information is now available on the whole 2.7-GHz sample and allows a comparison to be made with analogous samples selected at low frequencies. The large numbers of unresolved sources in the 2.7-GHz sample are not all flat-spectrum objects as is commonly thought; no less than 44 per cent have steep high-frequency spectra, with≽ 0.5. These unresolved steep-spectrum objects cannot be classified as either extended radio sources or ‘centimetre-excess’ compact objects; they form a distinct class of their own. Nevertheless, there is evidence that it may be useful to consider both compact and extended steep-spectrum sources together as a single population.