The Canada–France Redshift Survey – VII. Optical counterparts of microjansky radio sources
The Canada–France Redshift Survey – VII. Optical counterparts of microjansky radio sources
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加拿大-法国红移调查 – VII. 微扬斯基射电源的光学单位
DOI：
10.1093/mnras/276.4.1085
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发表时间：
1995
影响因子：
4.8
通讯作者：
T. Kenet
中科院分区：
文献类型：
--
作者：
F. Hammer;D. Crampton;S. Lilly;O. Fèvre;T. Kenet
在加拿大-法国红移巡天（CFRS）的过程中，对一个完整的S$>$16 $\mu$Jy射电望远镜样品的光学对应物进行了深度成像和光谱学研究。所有36个来源，但两个已被光学识别，光谱已获得其中23个。亮于$I_{AB} $0.7的射电辐射由活动星系核提供能量的早型星系、中等红移的星暴后星系和低红移的蓝发射线天体。根据它们的射电和光学性质，我们认为这11个比$I_{AB}>$22.5暗的天体大部分都是z$>$1的天体，其中一半可能是早型星系。我们的结论是，$\mu$Jy源的$\sim$40%可能在z $>$1。在z = 0.7以上的区域中，三分之一到一半的发光椭圆星系显示出中等强度的无线电发射（P $\sim $5 10$^{23}$ W Hz$^{-1}$），其强度至少是当地样本的10倍，可能反映了其核活动的演变。只有一个经典的星暴星系中确定的样本，其余的蓝色发射线对象显示的光学和无线电活动更典型的低功率AGN比星暴。后星暴在$\mu$Jy水平的数量是相当高的比mJy星暴星系的表面密度，这表明后者是前者的父母人口。虽然星暴星系被认为是mJy射电计数的主要贡献者，但大多数$\mu$Jy射电源似乎与活动星系核活动有关，而不是与正常星星有关
Deep imaging and spectroscopy have been carried out for optical counterparts of a complete sample of S$>$16 $\mu$Jy radiosources during the course of the Canada-France Redshift Survey (CFRS). All 36 sources but two have been optically identified, and spectra have been obtained for 23 of them. The objects brighter than $I_{AB} $0.7 early-type galaxies with radio emission powered by an AGN, intermediate redshift post-starburst galaxies, and lower redshift blue emission-line objects. From their radio and optical properties, it is argued that the 11 objects fainter than $I_{AB}>$22.5 are mostly at z$>$1, and one half of them are probably early-type galaxies. We conclude that $\sim$40 per cent of the $\mu$Jy sources are likely to be at z $>$1. Between one third and one half of the luminous ellipticals in this field beyond z = 0.7 show moderately powerful radio emission (P $\sim$ 5 10$^{23}$ W Hz$^{-1}$) which is at least 10 times more powerful than seen in local samples, and probably reflects evolution of the activity in their nuclei. Only one classical starburst galaxy is identified in the sample; the rest of the blue emission-line objects show optical and radio activity more typical of low power AGNs than starbursts. The number of post-starbursts at $\mu$Jy levels is considerably higher than the surface density of mJy starburst galaxies, suggesting the latter are the parent population of the former. While starburst galaxies are considered to be major contributors to the mJy radiosources counts, the majority of the $\mu$Jy radio sources appear to be related to AGN activity rather than to normal star