Observations of linear polarization in the 2-8 keV energy range with the
Imaging X-ray Polarimetry Explorer (IXPE) explore the magnetic field geometry
and dynamics of the regions generating non-thermal radiation in relativistic
jets of blazars. These jets, particularly in blazars whose spectral energy
distribution peaks at X-ray energies, emit X-rays via synchrotron radiation
from high-energy particles within the jet. IXPE observations of the X-ray
selected BL Lac-type blazar 1ES 1959+650 in 2022 May 3-4 showed a significant
linear polarization degree of Π_x = 8.0%± 2.3% at an
electric-vector position angle ψ_x = 123^∘± 8^∘.
However, in 2022 June 9-12, only an upper limit of Π_x≤ 5.1%
could be derived (at the 99
polarization at that time Π_O∼ 5% is comparable to the X-ray
measurement. We investigate possible scenarios for these findings, including
temporal and geometrical depolarization effects. Unlike some other X-ray
selected BL Lac objects, there is no significant chromatic dependence of the
measured polarization in 1ES 1959+650, and its low X-ray polarization may be
attributed to turbulence in the jet flow with dynamical timescales shorter than
1 day.
更多
查看译文
关键词
Relativistic jets,X-ray active galactic nuclei,Active galactic nuclei,Blazars,Polarimetry,Spectropolarimetry