Barres de Almeida, U. and Ward, M.J. and Dominici, T.P. and Abraham, Z. and Franco, G.A.P. and Daniel, M.K. and Chadwick, P.M. and Boisson, C. (2010) 'Particle acceleration and magnetic field structure in PKS2155-304 : optical polarimetric observations.', Monthly notices of the Royal Astronomical Society., 408 (3). pp. 1778-1787.
In this paper, we present multiband optical polarimetric observations of the very-high energy blazar PKS 2155−304 made simultaneously with a HESS/Fermi high-energy campaign in 2008, when the source was found to be in a low state. The intense daily coverage of the data set allowed us to study in detail the temporal evolution of the emission, and we found that the particle acceleration time-scales are decoupled from the changes in the polarimetric properties of the source. We present a model in which the optical polarimetric emission originates at the polarized mm-wave core and propose an explanation for the lack of correlation between the photometric and polarimetric fluxes. The optical emission is consistent with an inhomogeneous synchrotron source in which the large-scale field is locally organized by a shock in which particle acceleration takes place. Finally, we use these optical polarimetric observations of PKS 2155−304 at a low state to propose an origin for the quiescent gamma-ray flux of the object, in an attempt to provide clues for the source of its recently established persistent TeV emission.
|Keywords:||Polarization, BL Lacertae objects, PKS 2155−304, Jets.|
|Full text:||PDF (arXiv version) - Other (271Kb)|
|Publisher Web site:||http://dx.doi.org/10.1111/j.1365-2966.2010.17236.x|
|Publisher statement:||The definitive version is available at www.blackwell-synergy.com|
|Record Created:||30 Nov 2012 12:35|
|Last Modified:||04 Jan 2013 14:37|
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