منابع مشابه
Multifrequency Polarization Properties of Blazars
We report preliminary results of a 3-year multifrequency polarization campaign of 15 AGNs of blazar type, including bimonthly total and polarized intensity imaging at 7 mm with the VLBA. We find that the sources have two different dependences of degree of polarization on wavelength: sub-mm peaked or straight “polarization spectra”. The fractional polarization of the latter group increases with ...
متن کاملRoma-BZCAT: A multifrequency catalogue of Blazars
We present a new catalogue of blazars based on multi-frequency surveys and on an extensive review of the literature. Blazars are classified as BL Lacertae objects, as flat spectrum radio quasars or as blazars of uncertain/transitional type. Each object is identified by a root name, coded as BZB, BZQ and BZU for these three subclasses respectively, and by its coordinates. This catalogue is being...
متن کاملMultifrequency and Iue Campaigns on Blazars
The IUE contribution to the understanding of the blazar phenomenon has been of fundamental importance. Here I review the progress obtained with the latest multifrequency campaigns performed with IUE on two prototype objects, the BL Lac PKS 2155-304 and the highly polarized, superluminal quasar 3C 279.
متن کاملVLBA Observations of Blazars
VLBI observations of blazars provide the closest look at compact jets that are thought to be responsible for the variable emission of blazars from radio to γ-ray wavelengths. It appears that flux variability at different wavelengths is connected to changes in jet structure near its base. The changes happen on timescales of weeks or less, which require frequent VLBI monitoring to follow. Current...
متن کاملA multifrequency analysis of radio variability of blazars
We have carried out a multifrequency analysis of the radio variability of blazars, exploiting the data obtained during the extensive monitoring programs carried out at the University of Michigan Radio Astronomy Observatory (UMRAO, at 4.8, 8, and 14.5 GHz) and at the Metsähovi Radio Observatory (22 and 37 GHz). Two different techniques detect, in the Metsähovi light curves, evidences of periodic...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1987
ISSN: 0074-1809
DOI: 10.1017/s0074180900155305