Relation between BL Lacertae objects and flat-spectrum radio quasars

被引:41
作者
Fan, JH
机构
[1] Guangzhou Univ, Ctr Astrophys, Guangzhou 510400, Peoples R China
[2] Peking Univ, Chinese Acad Sci, Joint Astrophys Ctr, Beijing 100871, Peoples R China
[3] Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China
基金
中国国家自然科学基金;
关键词
BL Lacertae objects : general; galaxies : jets; quasars : general;
D O I
10.1086/374033
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Blazars have two subclasses, namely, BL Lacertae objects and flat-spectrum radio quasars. The two subclasses share many similar observational properties, but their difference in emission lines cannot be ignored. What causes the difference? In this Letter, we propose a method to determine the intrinsic ratio, f, of the comoving luminosity in the jet to the unbeamed luminosity and find that f in BL Lacertae objects is greater than that in flat-spectrum radio quasars. Therefore, the emission from the jet will dominate the unbeamed (line emission) part in BL Lacertae objects. However, in the case of flat-spectrum radio quasars, the emissions from the jet are comparable to the unbeamed part. We propose that the difference in f perhaps plays an important role in the different emission-line properties of BL Lacertae objects and flat-spectrum radio quasars and that there is no evolution effect between the two subclasses of blazars.
引用
收藏
页码:L23 / L24
页数:2
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