相关论文: Linear Spectropolarimetric Analysis of Fairall 9 w…
We analyze the optical properties of Radio-Loud quasars along the Main Sequence (MS) of quasars. A sample of 355 quasars selected on the basis of radio detection was obtained by cross-matching the FIRST survey at 20cm and the SDSS DR12…
Assuming a gravitational origin for the Fe III$\lambda\lambda$2039-2113 redshift and using microlensing based estimates of the size of the region emitting this feature, we obtain individual measurements of the virial factor, $f$, in 10…
We present a high-cadence multi-epoch analysis of dramatic variability of three broad emission lines (MgII, H$\beta$, and H$\alpha$) in the spectra of the luminous quasar ($\lambda L_{\lambda}$(5100\r{A}) = $4.7 \times 10^{44}$ erg…
We address the effect of the viewing angle of the accretion disk plane and the geometry of the broad-line region (BLR) with the goal of interpreting the distribution of quasars along the main sequence (MS). We utilize photoionization code…
We present high S/N UV spectra for eight quasars at z $\sim$ 3 obtained with VLT/FORS. The spectra enable us to analyze in detail the strong and weak emission features in the rest-frame range 1300-2000 A of each source (Ciii]$\lambda$1909,…
The main sequence offers a method for the systematization of quasar spectral properties. Extreme FeII emitters (or extreme Population A, xA) are believed to be sources accreting matter at very high rates. They are easily identifiable along…
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] We compare broad emission line profiles and estimate line ratios for all major emission lines between Ly-alpha and H-beta in a sample of six quasars. The sources were chosen with two criteria in mind: the existence of high…
Much effort has been done in order to better understand the active galactic nuclei mechanisms behind the relativistic jets observed in radio-loud sources. These phenomena are commonly seen in luminous objects with intermediate/high redshift…
The kinematics and morphology of the broad emission line region (BELR) of quasars are the subject of significant debate. The two leading methods for constraining BELR properties are microlensing and reverberation mapping. Here we combine…
A small fraction of quasars have long been known to show bulk velocity offsets in the broad Balmer lines with respect to the systemic redshift of the host galaxy. Models to explain these offsets usually invoke broad-line region gas…
A key to understanding quasar unification paradigms is the emission properties of broad absorption line quasars (BALQs). The fact that only a small fraction of quasar spectra exhibit deep absorption troughs blueward of the broad permitted…
A method is proposed for measuring the size of the broad emission line region (BLR) in quasars using broadband photometric data. A feasibility study, based on numerical simulations, points to the advantages and pitfalls associated with this…
In this work, we studied the broadband temporal and spectral properties of the flat-spectrum radio quasar (FSRQ) Ton 599. We collected the long-term data from Jan 2019 to August 2024 when the source was in a long flaring episode. We used…
The physical nature of the material responsible for the high--velocity, broad-absorption line features seen in a small fraction of quasar spectra has been the subject of debate since their discovery. This has been especially compounded by…
We address the effect of orientation of the accretion disk plane and the geometry of the broad-line region (BLR) as part of an effort to understand the distribution of quasars in the optical plane of the quasar main sequence. We utilize the…
Direct measurements of the masses of supermassive black holes (SMBHs) are key to understanding their growth and constrain their symbiotic relationship to their host galaxies. However, current methods used to directly measure black hole…
We present high S/N UV spectra for eight quasars at $z\sim3$\ obtained with VLT/FORS. The spectra enable us to analyze in detail the strongest emission features in the rest-frame range 1400-2000 \AA\ of each source (\ciii, \siiii, \aliii,…
Fairall 51 is a polar-scattered Seyfert 1 galaxy, a type of active galaxies believed to represent a bridge between unobscured type-1 and obscured type-2 objects. Fairall 51 has shown complex and variable X-ray absorption but only little is…
Roughly 10% of all quasars exhibit Broad Absorption Line (BAL) features which appear to arise in material outflowing at high velocity from the active galactic nucleus (AGN). The details of this outflow are, however, very poorly constrained…