The spectral energy distributions of blazars and the connections among XBLs, RBLs, and OVV quasars

Citation
Gz. Xie et al., The spectral energy distributions of blazars and the connections among XBLs, RBLs, and OVV quasars, PUB AST S J, 53(3), 2001, pp. 469-473
Citations number
27
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN
ISSN journal
0004-6264 → ACNP
Volume
53
Issue
3
Year of publication
2001
Pages
469 - 473
Database
ISI
SICI code
0004-6264(2001)53:3<469:TSEDOB>2.0.ZU;2-R
Abstract
In this paper, we introduce two composite spectral indices, alpha (xox) = a lpha (ox) - alpha (x) and alpha (oro) = alpha (or) - alpha (o). In the comp osite color-color (alpha (xox)-alpha (oro)) diagram, there are three region s: (1) For XBLs and XBL-like RBLs, the values of alpha (xox) is in the rang e of -1.0-0.0; (2) For RBLs, alpha (xox) is in 0.0-1.5, and alpha (oro) < - 0.75; (3) For OVV quasars, alpha (xox) is in 0.0-1.5 and the alpha (oro) > -0.75. Our results support the conclusion that RBLs are intermediate betwee n XBLs and OVV quasars, which has been given by Sambruna et al. (1996, AAA 65.159.120). On the other hand, based on the idea that a group of extragala ctic objects which can be regarded as a category with similar physical prop erties must fit the same relation, using the HST new observational data, we found that there is a strong correlation between the apparent magnitude of the host galaxies and log z for all BL Lac objects (XBLs + RBLs), but OVV quasars lie about 4 magnitude above the Hubble line of 86 BL Lacs. This imp lies that all XBL-like and XBLs belong to a single category with similar ph ysical properties, while OVV quasars and BL Lacs belong to different popula tions.