Optical spectroscopy of BL Lacertae objects
نویسندگان
چکیده
منابع مشابه
Eso Vlt Optical Spectroscopy of Bl Lacertae Objects. Iii. an Extension of the Sample
We present results of an ongoing program at the ESO VLT for spectroscopy of BL Lac objects lacking a firm redshift estimate and here we report on 15 objects. For 11 sources we confirm the BL Lac classification, and we determine new redshifts for 3 objects, 1 with weak emission lines (PKS 1057−79, z = 0.569) and 2 with absorptions from the host galaxy (RBS 1752, z = 0.449; RBS 1915, z = 0.243); ...
متن کاملRedshift limits of BL Lacertae objects from optical spectroscopy (Research Note)
Context. BL Lacertae objects have been the targets for numerous recent multiwavelength campaigns, continuum spectral variability studies, and theoretical spectral and variability modeling. A meaningful interpretation of the results of such studies requires a reliable knowledge of the objects’ redshifts; however, the redshifts for many are still unknown or uncertain. Aims. Therefore, we hope to ...
متن کاملOptical spectroscopy of BL Lacertae objects . Broad lines , companion galaxies and redshift lower limits
Aims. We present optical spectroscopy of a sample of BL Lac objects, to determine their redshift, to study their broad emission line properties and to characterize their close environment. Methods. Twelve objects were observed using the ESO 3.6m and the NOT 2.5m telescopes, obtaining spectra for the BL Lacs and for nearby sources. Results. For seven objects, nuclear emission lines and/or absorp...
متن کاملPolarization and Variations of BL Lacertae Objects
BL Lacertae objects are an extreme subclass of AGNs showing rapid and large-amplitude variability, high and variable polarization, and core-dominated radio emissions. If a strong beaming effect is the cause of the extreme observation properties, one would expect that these properties would be correlated with each other. Based on the relativistic beaming model, relationships between the polariza...
متن کاملThe Cosmological Evolution of BL Lacertae Objects
We review the main results from several radio, X-ray and multi-frequency surveys on the topic of cosmological evolution of BL Lacertae objects. Updated findings on BL Lac evolution following the recent identification of many sources in the ”Sedentary Multi-Frequency survey” are also discussed. By means of extensive Monte Carlo simulations we test some possible explanations for the peculiar cosm...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2006
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:20065455