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Evidence for cospatial optical and radio polarized emission in active galactic nuclei


Gabuzda, DC and Rastorgueva, EA and Smith, PS and O'Sullivan, SP, Evidence for cospatial optical and radio polarized emission in active galactic nuclei, Monthly Notices of the Royal Astronomical Society, 369, (4) pp. 1596-1602. ISSN 0035-8711 (2006) [Refereed Article]


Copyright Statement

Copyright 2006 The Authors. Journal compilation 2006 RAS

DOI: doi:10.1111/j.1365-2966.2006.10433.x


We investigate the relationship between the optical and radio emission of active galactic nuclei (AGN) by analysing optical and 15+22+43 GHz Very Long Baseline Array (VLBA) polarization observations simultaneous to within a day for 11 BL Lacertae (BL Lac) objects and the blazar 3C279. We have determined and corrected for the Faraday rotation measures in the very long baseline interferometry (VLBI) cores, enabling us to compare the intrinsic (zero-wavelength) VLBI-core polarization angles and the optical polarization angles χopt. A clear alignment between these two angles emerges in the transition toward higher radio frequencies, and a prominent peak at 0 is visible in the distribution of |χoptχ43 GHz|. This correlation implies that the magnetic-field orientations in the regions giving rise to the optical and radio polarization are the same, and can be easily understood if the radio and optical polarization are roughly cospatial. It is difficult to rule out the possibility that they arise in different regions in a straight jet with a uniform magnetic-field structure, but this seems less likely, since the VLBI jets of AGN are often bent on parsec-scales. This may suggest that much or all of the strong optical polarization in these sources arises in the inner radio jets, possibly associated with the formation and emergence of compact new VLBI components.

Item Details

Item Type:Refereed Article
Keywords:polarization galaxies, active galaxies, field galaxies, jets
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Cosmology and extragalactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Rastorgueva, EA (Dr Elizaveta Rastorgueva-Foi)
ID Code:93550
Year Published:2006
Web of Science® Times Cited:35
Deposited By:Mathematics and Physics
Deposited On:2014-08-07
Last Modified:2014-08-13
Downloads:331 View Download Statistics

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