Related papers: Variability in Low Ionization Broad Absorption Lin…
It has been known for 20 years that the absorbing gas in broad absorption line quasars does not completely cover the continuum emission region, and that partial covering must be accounted for to accurately measure the column density of the…
Quasar outflows have long been recognized as potential contributors to the co-evolution between supermassive black holes (SMBHs) and their host galaxies. The role of outflows in AGN feedback processes can be better understood by placing…
We present 13 Broad Absorption Line (BAL) quasars, including 12 new objects, which were identified in the Sloan Digital Sky Survey (SDSS) and matched within 2'' to sources in the FIRST radio survey catalog. The surface density of this…
We report the results of statistical tests performed on a sample of 139 broad absorption line (BAL) QSOs with good quality optical spectra and/or optical polarization data. Correlations between optical indices and the polarization degree…
We report the discovery of unusual broad absorption lines (BALs) in the bright quasar SDSS J075133.35+134548.3 at z~1, and present a detailed study of BAL and emission lines using the archived and newly obtained optical and NIR…
In this Letter, we report the discovery of a strong correlation between the variability of narrow absorption lines (NALs) and the ionizing continuum from a two-epoch spectra sample of 40 quasars containing 52 variable C iv…
Accounting for ~20% of the total QSO population, Broad Absorption Line QSOs are still an unsolved problem in the AGN context. They present wide troughs in the UV spectrum, due to material with velocities up to 0.2 c toward the observer. The…
We isolate a set of quasars that exhibit emergent C iv broad absorption lines (BALs) in their spectra by comparing spectra in the SDSS Data Release 7 and the SDSS/BOSS Data Releases 9 and 10. After visually defining a set of emergent BALs,…
We present a qualitative analysis of the variability of quasar broad absorption lines using the large multi-epoch spectroscopic dataset of the Sloan Digital Sky Survey Data Release 10. We confirm that variations of absorption lines are…
An experimental search for variation in the fundamental coupling constants is strongly motivated by modern high-energy physics theories. Comparison of quasar absorption line spectra with laboratory spectra provides a sensitive probe for…
It is thought that a class of broad absorption line (BAL) QSOs, characterised by Fe absorption features in their UV spectra (called `FeLoBALs'), could mark a transition stage between the end of an obscured starburst event and a youthful QSO…
Context. Quasar outflows are often analyzed to determine their ability to contribute to active galactic nucleus (AGN) feedback. We identified a broad absorption line (BAL) outflow in the VLT/UVES spectrum of the quasar SDSS J1321-0041. The…
We present Suzaku observations of three iron low-ionization broad absorption line quasars (FeLoBALs). We detect J1723+5553 (3\sigma) in the observed 2--10 keV band, and constrain its intrinsic nh column density to nh > 6\times10^{23} \cmsq…
We have studied a sample of 415 associated (z_ab z_em; relative velocity with respect to QSO <3000km/s) Mg II absorption systems with 1.0<=z_ab<=1.86, in the spectra of SDSS DR3 QSOs, to determine the dust content and ionization state in…
Recent observations of Broad Absorption Line (BAL) quasars demonstrated that the soft X-ray emission of these objects is extremely weak and convincing evidence for very strong absorption by a high column density (~ 10^23.5 cm^-2) was…
This paper presents an analysis of a Keck HIRES spectrum of the QSO FIRST J104459.6+365605. The line of sight towards the QSO contains two clusters of outflowing clouds that give rise to broad blue shifted absorption lines. The outflow…
We investigate the multi-phase gas surrounding QSOs traced by 33 absorption lines (e.g., Ly$\alpha$, C\,\textsc{iv}, Fe\,\textsc{ii}, Mg\,\textsc{ii}, etc.) in the stacked spectra of background sources, using the early data release from the…
In an ongoing infrared imaging survey of quasars at Keck Observatory, we have discovered that the z=1.285 quasar SDSS J233646.2-010732.6 comprises two point sources with a separation of 1.67". Resolved spectra show that one component is a…
Very few low-ionization broad absorption line (LoBAL) QSOs have been found at high redshifts to date. One high-redshift LoBAL QSO, J0122+1216, was recently discovered at the Lijiang 2.4-m Telescope with an initial redshift determination of…
We analyse high-resolution VLT+UVES spectra of the low-ionization intrinsic absorber observed in the BAL QSO SDSS J001130.56+005550.7. Two narrow absorption systems at velocities -600 km/s and -22000 km/s are detected. The low-velocity…