Related papers: Extreme High-velocity Outflows from High-redshift …
While narrow absorption lines (NALs) are relatively stable, broad absorption lines (BALs) and mini-BAL systems usually show violent time variability within a few years via a mechanism that is not yet understood. In this study, we examine…
AGN feedback is a well known mechanism in the evolution of galaxies. One open question is the driving mechanism of galaxy-scale outflows. At low redshift, radio jets often interact with the ISM, generating turbulence and driving ionized…
AGN-driven outflows are invoked by galaxy evolutionary models to quench star formation and to explain the origin of the relations observed locally between super massive black holes and their host galaxies. This work aims to detect the…
Galactic outflows driven by rapidly-accreting quasars at high redshift are widely expected to play a key role in the short- and long-term future evolution of their host galaxies. Using new and archival ALMA data, we observed the OH 119um…
A substantial fraction of quasars display broad absorption lines (BALs) in their rest-frame ultraviolet spectra. While the origin of BALs is thought to be related to the accretion disc wind, it remains unclear whether the observed ratio of…
We test a scenario claiming that the broad absorption line (BAL) phenomenon in quasars (QSOs) is not a temporary stage of their life. In this scenario, we see the BAL effect only if the line of sight is within a spatially limited and…
We present six new and two previously published high-resolution spectra of the quasar HS 1603+3820 (z_em = 2.542) taken over an interval of 4.2 years (1.2 years in the quasar rest frame). The observations were made with the High-Dispersion…
We present an observational study of wind acceleration based on four low-ionization broad absorption line (LoBAL) quasars (J0136, J1238, J1259, J1344). J0136 and J1344 (group-1) are radio quiet and show large BAL-velocity shifts as opposed…
Fast (~1000 km/s) outflows of neutral gas (from 21-cm HI absorption) are detected in strong radio sources. The outflows occur, at least in some cases, at distances from the radio core that range between few hundred parsecs and kpc. These HI…
We conducted a survey of quasar outflows using the VLT/X-shooter spectrograph. When choosing the 14 BAL and mini-BALs comprising this sample, the data did not cover the S IV and S IV* troughs, whose ratio can be used to determine the…
We report spectropolarimetry of 30 radio-selected broad absorption line (BAL) quasars with the Keck Observatory, 25 from the sample of Becker et al. (2000). Both high and low-ionization BAL quasars are represented, with redshifts ranging…
The origin of broad-absorption-line quasars (BAL QSOs) is still an open issue. Accounting for ~20% of the QSO population, these objects present broad absorption lines in their optical spectra generated from outflows with velocities up to…
Outflows up to 1500 km/s of atomic neutral hydrogen are detected in a growing number of radio galaxies. Outflows with similar velocities are also detected in ionized gas, suggesting a common origin for the extreme kinematics of these two…
We report the detection of fast (~ 1000 km/s), massive outflows of neutral gas observed -- using the WSRT -- as 21-cm HI absorption against the strong radio continuum of seven radio sources. The neutral outflows occur, in at least somes…
Among the unusual broad absorption line quasars being found by the Sloan Digital Sky Survey (SDSS) are objects with much stronger absorption in Fe III than Fe II. These unusual line ratios require a high density in the outflow (n_H >= 3 x…
Recent X-ray observations show absorbing winds with velocities up to mildly-relativistic values of the order of ~0.1c in a limited sample of 6 broad-line radio galaxies. They are observed as blue-shifted Fe XXV-XXVI K-shell absorption…
We examine the UV and X-ray properties of 256 radio-quiet SDSS quasars (QSOs) observed in X-rays with Chandra and/or XMM-Newton in order to study the relationship between QSOs with broad CIV absorption lines (BALs; width >2000 km/s) and…
Luminous quasars are powerful targets to investigate the role of feedback from supermassive black-holes (BHs) in regulating the growth phases of BHs themselves and of their host galaxies, up to the highest redshifts. Here we investigate the…
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 a summary of our recent results on gas outflows in radio galaxies. Fast outflows (up to 2000 km/s) have been detected both in ionized and neutral gas. The latter is particularly surprising as it shows that, despite the extremely…