Related papers: Orientation effects in quasar spectra: The broad- …
We recently proposed the equivalent width (EW) of the narrow [OIII]5007{\AA} emission line as an orientation indicator for active galactic nuclei. We tested this method on about $12,300$ optically selected broad line quasars from the SDSS…
We present an analysis of the orientation effects in SDSS quasar composite spectra. In a previous work we have shown that the equivalent width EW of the [OIII] {\lambda}5008{\AA} line is a reliable indicator of the inclination of the…
The relative brightnesses of strongly lensed quasar images, called flux ratios, respond to perturbations from low-mass dark matter halos, enabling tests of dark matter models. The quasar narrow-line region (NLR) is ideal for flux-ratio…
We present an analysis of the average spectral properties of 12,000 SDSS quasars as a function of accretion disc inclination, as measured from the equivalent width of the [O III] 5007{\AA} line. The use of this indicator on a large sample…
In this paper we report new evidence that measurements of the broad-line widths in quasars are dependent on the source orientation, consistent with the idea that the broad-line region is flattened or disc-like. This reinforces the view…
We present high resolution radio data at 3.5 and 20 cm from the VLA in the A configuration for 144 quasars with known CIV absorption line properties. Using these measurements, we compare and contrast a number of quasar orientation…
We investigate the correlations between spectral index, jet side and extent of the radio lobes for a sample of nearby FRII radio galaxies. In Dennett-Thorpe et al. (1997) we studied a sample of quasars and found that the high surface…
Since the discovery of active galactic nuclei (AGN) and their subclasses, a unification scheme of AGN has been long sought. Orientation-based unified models predict that some of the diversity within AGN subclasses can be explained by the…
Several observed spectral properties of quasars are believed to be influenced by quasar orientation. In this investigation we examine the effect of orientation on the Mg II line located at 2798 {\AA} in a sample of 36 radio-loud quasars,…
The interpretation of the main sequence of quasars has become a frontier subject in the last years. The consider the effect of a highly flattened, axially symmetric geometry for the broad-line region (BLR) on the parameters related to the…
(Abridged) With the largest homogeneous quasar sample with optical spectra and robust radio morphology classifications assembled to date, we investigate quasar radio and optical properties with unprecedented statistical power. The data…
We investigate the orientation dependence of the spectral energy distributions in a sample of radio-loud quasars. Selected specifically to study orientation issues, the sample contains 52 sources with redshifts in the range 0.16<z<1.4 and…
We present optical spectropolarimetric and imaging polarimetric observations of four high-redshift radio galaxies (HzRGs) obtained with the 10-m Keck I telescope. A broad Mg II emission line is detected in the total and polarized flux…
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…
We perform a systematic study of outflow in the narrow-line region (NLR) of active galactic nuclei (AGNs) at $z\sim0.4-0.8$ basing upon a large sample of $\sim900$ quasars at $z\sim 0.4-0.8$. The sample is extracted from the Sloan Digital…
With a quasar sample designed for studying orientation effects, we investigate the orientation dependence of characteristics of the C IV 1549 broad emission line in approximately 50 Type 1 quasars with z=0.1-1.4. Orientation is measured for…
In a single optical spectrum, the quasar narrow-line region (NLR) reveals low density, photoionized gas in the host galaxy interstellar medium, while the immediate vicinity of the central engine generates the accretion disk continuum and…
We highlight a representative sample of active galactic nuclei selected independent of orientation. The defining characteristic of the selection is sophisticated matching between the $0.1<z<0.6$ Sloan Digital Sky Survey quasars from the…
We searched for the presence of extended emission-line regions (EELRs) around low-redshift QSOs. We observed a sample of 20 mainly radio-quiet low-redshift quasars (z<0.3) by means of integral field spectroscopy. After decomposing the…
We investigate correlations between the direction of the optical linear polarization and the orientation of the host galaxy/extended emission for type1 and type2 radio-loud and radio-quiet quasars. We have used high resolution Hubble Space…