The evolution of galaxies in radio-selected groups.
The evolution of galaxies in radio-selected groups.
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DOI：
10.1086/172305
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发表时间：
1993-02
期刊：
影响因子：
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通讯作者：
J. Allington-Smith;R. Ellis;E. Zirbel;A. Oemler
中科院分区：
文献类型：
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作者：
J. Allington-Smith;R. Ellis;E. Zirbel;A. Oemler
基于对98个强射电星系周围的星系群的观测，以一种不受选择效应影响的方式研究了小群体星系的演化，其中65个红移小于0.25,33个红移在0.25到0.50之间。分析了射电星系0.5 Mpc范围内M(V)不大于-19.0的星系的性质。人们发现，强射电星系出现在丰度范围很广的星系群中，但没有一般星系群那么广。自z = 0.4观测到的年代以来，射电群的丰富度略有下降，特别是在FR II源中。高红移和低红移射电群成员的光度函数与附近的场星系难以区分。结果表明，包含射电星系的星系群通常是典型的星系群成员，是对正常星系性质的良好探索。认为形态与环境的关系是近代形成的，并随着时间的推移而迅速变陡。
The evolution of galaxies in small groups is studied in a way unbiased by selection effects, on the basis of observations of the populations of galaxies around a sample of 98 strong radio galaxies, 65 with redshifts less than 0.25, and 33 with redshifts between 0.25 and 0.50. The properties of galaxies with M(V) not greater than -19.0 within 0.5 Mpc of the radio galaxies are analyzed. Strong radio galaxies are found to occur in groups whose range of richness is broad, but not as broad as that of groups in general. There has been a slight decrease in the richness of radio groups since the epoch observed at z of 0.4, particularly among the FR II sources. The luminosity function of the members of both high- and low-redshift radio groups is indistinguishable from that of nearby field galaxies. It is concluded that galaxies in groups containing radio galaxies are typical of group members in general and are a good probe of the properties of normal galaxies. It is suggested that the morphology-environment relation is of recent origin and is steepening rapidly with time.