skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A study of BL Lacertae-type objects with Exosat. I. Flux correlations, luminosity variability, and spectral variability

Abstract

Results are presented on a systematic analysis of more than 200 X-ray observations on 36 BL Lac objects, obtained from the Exosat archive, providing further strong evidence that the population of currently known BL Lac objects can be divided into two subclasses, Q-BL Lacs and X-BL Lacs. The subclass Q-BL Lacs includes most of the classical radio-discovered BL objects which are characterized by a continuum energy distribution, from radio to X-rays, similar to that of flat-radio-spectrum QSOs, highly polarized quasars, and optically violent variable QSOs. The subclass X-BL Lacs includes all the BL Lac objects which were detected in high-frequency surveys (i.e., optical and X-ray). This subclass is characterized by a very smooth energy distribution from radio to X-rays, which is often considered to be the signature of synchrotron emission. 96 refs.

Authors:
; ; ; ;  [1]
  1. (EXOSAT Observatory, Noordwijk (Netherlands) CNR, Istituto di Fisica Cosmica, Milan (Italy))
Publication Date:
OSTI Identifier:
6698270
Alternate Identifier(s):
OSTI ID: 6698270
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; (USA); Journal Volume: 356
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BL LACERTAE OBJECTS; CLASSIFICATION; X RADIATION; ABSORPTION SPECTRA; COSMIC X-RAY SOURCES; ENERGY SPECTRA; GALAXY NUCLEI; LUMINOSITY; POPULATIONS; SATELLITES; SPECTROSCOPY; SYNCHROTRON RADIATION; BREMSSTRAHLUNG; COSMIC RADIO SOURCES; COSMIC RAY SOURCES; ELECTROMAGNETIC RADIATION; IONIZING RADIATIONS; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; RADIATIONS; SPECTRA 640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar, Radio & X-Ray Sources

Citation Formats

Giommi, P., Barr, P., Pollock, A.M.T., Garilli, B., and Maccagni, D. A study of BL Lacertae-type objects with Exosat. I. Flux correlations, luminosity variability, and spectral variability. United States: N. p., 1990. Web. doi:10.1086/168851.
Giommi, P., Barr, P., Pollock, A.M.T., Garilli, B., & Maccagni, D. A study of BL Lacertae-type objects with Exosat. I. Flux correlations, luminosity variability, and spectral variability. United States. doi:10.1086/168851.
Giommi, P., Barr, P., Pollock, A.M.T., Garilli, B., and Maccagni, D. Fri . "A study of BL Lacertae-type objects with Exosat. I. Flux correlations, luminosity variability, and spectral variability". United States. doi:10.1086/168851.
@article{osti_6698270,
title = {A study of BL Lacertae-type objects with Exosat. I. Flux correlations, luminosity variability, and spectral variability},
author = {Giommi, P. and Barr, P. and Pollock, A.M.T. and Garilli, B. and Maccagni, D.},
abstractNote = {Results are presented on a systematic analysis of more than 200 X-ray observations on 36 BL Lac objects, obtained from the Exosat archive, providing further strong evidence that the population of currently known BL Lac objects can be divided into two subclasses, Q-BL Lacs and X-BL Lacs. The subclass Q-BL Lacs includes most of the classical radio-discovered BL objects which are characterized by a continuum energy distribution, from radio to X-rays, similar to that of flat-radio-spectrum QSOs, highly polarized quasars, and optically violent variable QSOs. The subclass X-BL Lacs includes all the BL Lac objects which were detected in high-frequency surveys (i.e., optical and X-ray). This subclass is characterized by a very smooth energy distribution from radio to X-rays, which is often considered to be the signature of synchrotron emission. 96 refs.},
doi = {10.1086/168851},
journal = {Astrophysical Journal; (USA)},
number = ,
volume = 356,
place = {United States},
year = {Fri Jun 01 00:00:00 EDT 1990},
month = {Fri Jun 01 00:00:00 EDT 1990}
}