Related papers: Microlensing of Broad Absorption Line Quasars: Pol…
The large magnification factors of gravitationally lensed (GL) systems allow us to investigate the properties of quasars with X-ray luminosities that are substantially lower than those of unlensed ones and also provide an independent means…
We report on an observation of the Broad Absorption Line (BAL) quasar PG 1115+080 performed with the XMM-Newton observatory. Spectral analysis reveals the second case of a relativistic X-ray absorbing outflow in a BAL quasar. The first case…
If the disappearance of the broad emission lines observed in changing-look quasars originates from the obscuration of the quasar core by dusty clouds moving in the torus, high linear optical polarization would be expected in those objects.…
We have built a sample of 74 radio-selected broad absorption line quasars from the Sloan Digital Sky Survey Data Release 5 (SDSS DR5) and Faint Images of the Radio Sky at Twenty Centimeters (FIRST), along with a well matched sample of 74…
We present the variability study of broad absorption lines (BALs) in a uniformly radio-selected sample of 28 BAL quasars using the archival data from the FIRST Bright Quasar Survey (FBQS) and the Sloan Digital Sky Survey (SDSS), as well as…
We present the results of a multi-wavelength study of a sample of high-redshift Radio Loud (RL) Broad Absorption Line (BAL) quasars. This way we extend to higher redshift previous studies on the radio properties, and broadband optical…
We investigate the correlation between rest-frame UV flux variability of broad absorption line (BAL) quasars and their variability in BAL equivalent widths (EWs) in a various timescale from $<10$~days to a few years in the quasar…
We report the first systematic search for blazars among broad-absorption-line (BAL) quasars. This is based on our intranight optical monitoring of a well-defined sample of 10 candidates selected on the criteria of a flat spectrum and an…
In this paper we present an analysis of absorption line variability in mini-BAL quasar LBQS 1206+1052. The SDSS spectrum demonstrates that the absorption troughs can be divided into two components of blueshift velocities of $\sim$700 km…
The results of a sub-millimeter survey of SDSS broad CIV absorption line quasars is discussed. It is found that the sub-millimeter flux distribution of BAL quasars is similar to that of non-BAL quasars. This is consistent with the idea that…
We investigate broad absorption line (BAL) disappearance and emergence using a 470 BAL-quasar sample over < 0.10-5.25 rest-frame years with at least three spectroscopic epochs for each quasar from the Sloan Digital Sky Survey. We identify…
The WISSH quasars project aims at studying the nuclear and host galaxy properties of the most luminous quasars ($L_{bol}>10^{47}$ erg/s, $1.8<z<4.6$). Nuclear winds are manifested as UV broad ($\geq$ 2,000 km/s) absorption lines (BAL) in…
We recently presented radio observations of a large sample of radio-loud broad absorption line (BAL) quasars from the SDSS and FIRST surveys, as well as a well matched sample of unabsorbed quasars, primarily to measure their radio spectral…
We investigate C IV broad absorption line (BAL) variability within a sample of 46 radio-loud quasars (RLQs), selected from SDSS/FIRST data to include both core-dominated (39) and lobe-dominated (7) objects. The sample consists primarily of…
The ultraviolet broad absorption lines have been seen in the spectra of quasars at high redshift, and are generally considered to be caused by outflows with velocities from thousands kilometers per second to one tenth of the speed of light.…
Several studies have shown that the column densities inferred from broad absorption lines (BALs) require extremely high metallicities and phosphorus overabundances -- apparently in conflict with other abundance diagnostics. Here I use HST…
High velocity (HV) outflows are an important but poorly understood aspect of quasar/SMBH evolution. Outflows during the luminous accretion phase might play a critical role in "unveiling" young dusty AGN and regulating star formation in the…
While C IV is the most common absorption line in Broad Absorption Line Quasar spectra, Balmer absorption lines are among the rarest. We present analysis of Balmer absorption in a sample of fourteen iron low-ionization BAL quasars…
Despite all the studies, the geometry of the wind at the origin of the blueshifted broad absorption lines (BAL) observed in nearly 20% of quasars still remains a matter of debate. We want to see if a two-component polar+equatorial wind…
Gravitational microlensing is a powerful tool allowing one to probe the structure of quasars on sub-parsec scale. We report recent results, focusing on the broad absorption and emission line regions. In particular microlensing reveals the…