相关论文: Alignment of quasar polarizations with large-scale…
We present polarization data for 32 mainly southern pulsars at 8.4 GHz. The observations show that the polarization fraction is low in most pulsars at this frequency except for the young, energetic pulsars which continue to show…
Extreme-scale alignment of quasar optical polarization vectors at cosmological scales ($z\le 2$) is also characterized by the rotation of mean position angle $\chi$ with $\Delta \chi \approx 30^{\circ}$ per 1 Gpc. For observing interval of…
We propose that the majority of quasars at redshift $z\sim 1 - 5$ formed in the environment of new born collapsed halos with 1-D velocity dispersion $\sigma_v^{1d} \sim 400 \kms$. The harboring coefficient $f$ of quasars per halo and the…
We performed an integrated optical polarization survey of 70 nearby galaxies to study the relationship between linear polarization and galaxy properties. To date this is the largest survey of its kind. The data were collected at McDonald…
We have conducted spectropolarimetry of 12 type II (obscured) quasar candidates selected from the spectroscopic database of the Sloan Digital Sky Survey based on their emission line properties. Polarization was detected in all objects, with…
It has been argued that certain broad absorption line quasars are viewed within 35 degrees of the axis of a relativistic radio jet, based on two-epoch radio flux density variability. It is true if the surface brightness of a radio source is…
During analysis of the relation of quasars to galaxies in the 2dF deep field a concentration of quasars was noted. Most striking was the closeness in redshift of 14 quasars about the mean redshift z = 2.149 with a range of $\pm 0.018$. The…
Semi-analytic models of galaxy formation postulate the existence of virialized gaseous halos around galaxies at high redshifts. A small fraction of the light emitted by any high-redshift quasar is therefore expected to scatter off the free…
We have obtained spectropolarimetric observations of the four images of the gravitationally lensed broad absorption line quasar H1413+117. The polarization of the microlensed image D is significantly different both in the continuum and in…
The reported alignment between the projected spin-axes and proper motion directions of pulsars is revisited in the light of new data from Jodrell Bank and Effelsberg. The present investigation uses 54 pulsars, the largest to date sample of…
Given the anisotropic emission from quasar accretion discs, their viewing angle affects estimates of the quasar luminosity, black-hole mass and Eddington ratio. Discs appear overluminous when viewed pole-on and underluminous when viewed at…
The variability of quasars across multiple wavelengths is a useful probe of physical conditions in active galactic nuclei. In particular, variable accretion rates, instabilities, and reverberation effects in the accretion disk of a…
A sample of 16 quasars selected from the Large Bright Quasar Survey in the redshift range 0.4 < z < 0.5 has been imaged in the R band with the Planetary Camera on the WFPC2 instrument of the Hubble Space Telescope. The host galaxy…
Many radio sources like quasars, blazars, radio galaxies, and micro-quasars exhibit circular polarisation (CP) with surprising temporal persistent handedness. As a possible explanation we propose that the CP is due to Faraday conversion…
The standard axion-like particle explanation of the observed large-scale coherent orientations of quasar polarisation vectors is ruled out by the recent measurements of vanishing of circular polarisation. We introduce a more general…
The integrated spectrum of OH emission from late-type stars is often circularly polarized, by as much as 50% in some cases. While the spectra are partially polarized, the individual maser components revealed by VLBI are much more so. Using…
Here, we revisit the polarization signal in caustic-crossing binary microlensing and introduce the maps of the polarization signals of the source star as a function of its position projected on the lens plane. The behavior of these maps…
We report observations of the linear polarisation of a sample of 50 nearby southern bright stars measured to a median sensitivity of $\sim$4.4 $\times 10^{-6}$. We find larger polarisations and more highly polarised stars than in the…
In the unified schemes for extragalactic radio sources, the quasars and BL Lac objects are intrinsically similar to the Fanaroff-Riley class II and I radio galaxies respectively, but appear to be different because they are viewed at…
Quasar pairs are either physically distinct binary quasars or the result of gravitational lensing. The majority of known pairs are in fact lenses, with a few confirmed as binaries, leaving a population of objects that have not yet been…