Related papers: Quasar winds caught on acceleration and decelerati…
We present the results of recent Chandra, XMM-Newton, and Hubble Space Telescope observations of the radio-loud (RL), broad absorption line (BAL) quasar PG 1004+130. We compare our new observations to archival X-ray and UV data, creating…
We conduct a spectroscopic search of quasars observed by the Sloan Digital Sky Survey (SDSS) with broad absorption line (BAL) troughs due to Mg II and troughs due to Fe II that simultaneously exhibit strong Balmer narrow emission lines…
We present a catalog of 5039 broad absorption line (BAL) quasars (QSOs) in the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) QSO catalog that have absorption troughs covering a continuous velocity range >= 2000 km/s. We have fit…
We present a time-variability analysis of 29 broad absorption line quasars (BALQSOs) observed in two epochs by the Sloan Digital Sky Survey (SDSS). These spectra are selected from a larger sample of BALQSOs with multiple observations by…
This work provides evidence that a large fraction of \ion{C}{IV} narrow absorption lines (NALs) seen along the line of sight to distant quasars are due to accretion disk winds, while also seeking to understand the relationship between NALs…
We aim to find out the reason why there exists an anisotropic HI absorption around quasars; i.e., the environments around quasars are highly biased toward producing strong HI absorption in transverse direction while there exists a…
We report the discovery of five broad-absorption-line (BAL) QSOs in a complete sample of 111 ultraviolet excess (UVX) QSO candidates also detected in the NRAO VLA Sky Survey. All five BAL QSOs, which include two high-ionization BAL QSOs and…
We study the time variability of five Fe Low ionization Broad Absorption Line (FeLoBAL) QSOs using repeated spectroscopic observations with the 2m telescope at IUCAA Girawali observatory (IGO) spanning an interval of upto 10 years. We…
Luminous quasars powered by accretion onto billion solar mass black holes already exist at the epoch of Reionisation, when the Universe was 0.5-1 Gyr old. These objects likely reside in over-dense regions of the Universe, and will grow to…
The disk wind, which is powered by the radiation force due to spectral lines (line force), is studied for broad absorption line (BAL) quasars. We investigate the structure of the disk wind based on the non-hydrodynamic method and compare…
The origin of radio emission in different populations of radio-quiet quasars is relatively unknown, but recent work has uncovered various drivers of increased radio-detection fraction. In this work, we pull together three known factors:…
The galactocentric distance of quasar absorption outflows are conventionally determined using absorption troughs from excited states, a method hindered by severely saturated or self-blended absorption troughs. We propose a novel method to…
Narrow absorption line (NAL) outflows are an important yet poorly understood part of the quasar outflow phenomenon. We discuss one particular NAL outflow that has high speeds, time variability, and moderate ionizations like typical BAL…
We present high-angular resolution (0.068", ~400pc) ALMA imaging of the [CII] line and dust continuum emission of PSO J352.4034-15.3373, a radio-loud quasar at z=5.83. The observations reveal a remarkably close match between the orientation…
It is widely accepted that the broad absorption line region (BALR) exists in most (if not all) quasars with a small covering factor. Recent works showed that the BALR is optically thick to soft and even medium energy X-rays, with a typical…
We present results from multi-epoch spectral analysis of XMM-Newton and Chandra observations of the broad absorption line (BAL) quasar APM 08279+5255. Our analysis shows significant X-ray BALs in all epochs with rest-frame energies lying in…
We present a study of a luminous, z=0.15, type-2 quasar (log [L([OIII])/(erg/s)]=42.8) from the Quasar Feedback Survey. It is classified as 'radio-quiet' (log [L(1.4 GHz)/(W/Hz)]=23.8); however, radio imaging reveals ~1 kpc low-power jets…
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…
We compile a large sample of broad absorption lines (BAL) quasars with X-ray observations from the \xmm archive data and Sloan Digital Sky Survey Data Release 5. The sample consists of 41 BAL QSOs. Among 26 BAL quasars detected in X-ray,…
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…