Related papers: Circular Polarization in AGN
The polarization properties of radio sources powered by an Active Galactic Nucleus (AGN) have attracted considerable attention because of the significance of magnetic fields in the physics of these sources, their use as probes of plasma…
Continuum and emission-line variability of active galactic nuclei provides a powerful probe of microarcsecond scale structures in the central regions of these sources. In this contribution, we review basic concepts and methodologies used in…
The latest results of the most detailed analysis of multi-epoch polarization-sensitive observations of active galactic nuclei (AGN) jets at parsecs scales by very long baseline interferometry (VLBI) reveal several characteristic patterns of…
We report here the detection of circular polarization in the Galactic Center black hole candidate, Sagittarius A*. The detection was made at 4.8 GHz and 8.4 GHz with the Very Large Array. We find that the fractional circular polarization at…
Alternative theories of gravity predict up to six distinct polarization modes for gravitational waves. Strong gravitational lensing of gravitational waves allows us to probe the polarization content of these signals by effectively…
This paper considers the problem of accurate measurement of circular polarization in imaging spectral-line VLBI observations in the lambda=7 mm and lambda=3 mm wavelength bands. This capability is especially valuable for the full…
The measurements of the linear polarisation of visible light from quasars give strong evidence for large-scale coherent orientations of their polarisation vectors in some regions of the sky. We show that these observations can be explained…
Forthcoming radio surveys will include full polarisation information, which can be potentially useful for weak lensing observations. We propose a new method to measure the (integrated) gravitational field between a source and the observer,…
The anisotropic nature of active galactic nuclei (AGN) is thought to be responsible for the observational differences between type-1 (pole-on) and type-2 (edge-on) nearby Seyfert-like galaxies. In this picture, the detection of emission…
We report here multi-epoch, multi-frequency observations of the circular polarization in Sagittarius A*, the compact radio source in the Galactic Center. Data taken from the VLA archive indicate that the fractional circular polarization at…
The general picture of how thermal AGNs work has become clearer in recent years but major observational puzzles threaten to undermine this picture. These puzzles include AGNs with extremely asymmetric emission line profiles, inconsistent…
According to the standard paradigm, the strong and compact luminosity of active galactic nuclei (AGN) is due to multi-temperature black body emission originating from an accretion disk formed around a supermassive black hole. This central…
Results of multi-frequency VLBA polarization imaging for sources showing evidence of quasi-periodic variations in their total flux density are discussed. Possible origins of the observed behavior are proposed.
From the analysis of measurements of the linear polarisation of visible light coming from quasars, the existence of large-scale coherent orientations of quasar polarisation vectors in some regions of the sky has been reported. Here, we show…
The extended X-ray emission observed in the direction of several molecular clouds in the central molecular zone of our Galaxy exhibits spectral and temporal properties consistent with the X-ray echo scenario. This concept postulates that…
Small amplitude inhomogeneous plane waves propagating in any direction in a homogeneously deformed Hadamard material are considered. Conditions for circular polarization are established. The analysis relies on the use of complex vectors (or…
A new theory is presented for the development of circular polarization as radio waves propagate through the turbulent, birefringent interstellar medium. The fourth order moments of the wavefield are calculated and it is shown that…
X-ray astronomy allows study of objects which may be associated with compact objects, i.e. neutron stars or black holes, and also may contain strong magnetic fields. Such objects are categorically non-spherical, and likely non-circular when…
We consider the polarization arising from scattering in an envelope illuminated by a central anisotropic source. Spherical harmonics are used to describe both the light source anisotropy and the envelope density distribution functions of…
We update the systematic studies of circular polarization in integrated pulse profiles by Han et al (1998). Data of circular polarization profiles are compiled. Sense reversals can occur in core or cone components, or near the intersection…