Multifrequency polarization properties of blazars

S. Jorstad, A. Marscher, J. Stevens, P. Smith, J. Forster, M. Lister, A. Stirling, J. Gómez, T. Cawthorne, W. Gear, I. Robson

Research output: Contribution to journalConference articlepeer-review

6 Scopus citations


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 frequency. All sources with sub-mm peak polarization (6 objects) have similar degree of polarization in the optical region and in the VLBA core. In high-optically polarized sources (5 objects) the EVPAs at all frequencies align with the pc-scale jet direction within the 1σ uncertainties. This implies that the high frequency emission is co-spatial with the VLBI core and/or transverse shocks in the jet.

Original languageEnglish (US)
Pages (from-to)247-252
Number of pages6
JournalChinese Journal of Astronomy and Astrophysics
Issue numberSUPPL. 1
StatePublished - 2006
Event6th International Workshop on Multifrequency Behaviour of High Energy Cosmic Sources: Frascati Workshop 2005 - Vulcano, Italy
Duration: May 23 2005May 28 2005


  • 3C 120)
  • 3C 273
  • 3C 279
  • 3C 345
  • 3C 454.3)
  • Active
  • BL Lac)
  • CTA 102
  • Galaxies: BL Lacertae objects: individual (3C 66A
  • Galaxies: individual (3C 111
  • Galaxies: jet
  • Galaxies: quasars: individual (0420-014
  • OJ 287
  • PKS 1510-089

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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