English
Related papers

Related papers: A multi-wavelength continuum characterization of h…

200 papers

We present a detailed study of the optical and NIR emission and absorption line spectrum of the quasar SDSS J163345.22+512748.4. We discovered on the newly acquired NIR spectrum a highly meta-stable neutral helium broad absorption line…

Astrophysics of Galaxies · Physics 2022-04-01 Bo Liu , Hongyan Zhou , Xinwen Shu , Shaohua Zhang , Tuo Ji , Xiang Pan , Peng Jiang

We systematically investigate short-timescale ($<$10-day rest-frame) CIV broad absorption-line (BAL) variability to constrain quasar-wind properties and provide insights into BAL-variability mechanisms in quasars. We employ data taken by…

We conducted the first multi-frequency polarimetric imaging of four broad absorption line (BAL) quasars using Very Long Baseline Array at milli-arcsecond resolutions to investigate the inclination of the non-thermal jet and test the…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Takayuki J. Hayashi , Akihiro Doi , Hiroshi Nagai

Broad absorption line (BAL) quasars have been studied for over thirty years. Yet it is still unclear why and when we observe broad absorption lines in quasars. Is this phenomenon caused by geometry or is it connected with the evolution…

Astrophysics of Galaxies · Physics 2014-06-19 Maciej Ceglowski , Magdalena Kunert-Bajraszewska , Bogna Pazderska , Marcin Gawronski

The broad absorption line (BAL) features seen in a small fraction of quasar optical/UV spectra are attributed to bulk outflows away from the quasar core. Observational evidence suggests that dust plays a key role in these systems, although…

Astrophysics · Physics 2009-11-10 Geraint F. Lewis , Scott C. Chapman , Zdenka Kuncic

XMM-Newton observations of 29 high redshift (z>2) quasars, including seven radio-quiet, 16 radio-loud and six Broad Absorption Line (BAL) objects, are presented; due to the high redshifts, the rest-frame energy bands extend up to \~30-70…

Astrophysics · Physics 2009-11-13 K. L. Page , J. N. Reeves , P. T. O'Brien , M. J. L. Turner

We analyze the long-term (rest-frame 3-30 yr) X-Ray variability of eleven broad absorption line (BAL) quasars, mainly to constrain the variation properties of the X-Ray absorbing shielding gas that is thought to play a critical role in BAL…

High Energy Astrophysical Phenomena · Physics 2015-06-11 Cristian Saez , William N. Brandt , Sarah C. Gallagher , Franz E. Bauer , Gordon P. Garmire

Broad absorption lines (BALs) in quasar spectra identify high velocity outflows that likely exist in all quasars and could play a major role in feedback to galaxy evolution. Studying the variability in these BALs can help us understand the…

Cosmology and Nongalactic Astrophysics · Physics 2012-04-30 Daniel M. Capellupo , Fred Hamann , Joseph C. Shields , Jules Halpern , Paola Rodríguez Hidalgo , Tom A. Barlow

Broad absorption lines (BALs) in quasar spectra indicate high-velocity outflows that may be present in all quasars and could be an important contributor to feedback to their host galaxies. Variability studies of BALs help illuminate the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Daniel M. Capellupo , Fred Hamann , Joseph C. Shields , Paola Rodríguez Hidalgo , Tom A. Barlow

We investigate the variability of CIV 1549A broad absorption line (BAL) troughs over rest-frame time scales of up to ~7 yr in 14 quasars at redshifts z>2.1. For 9 sources at sufficiently high redshift, we also compare CIV and SiIV 1400A…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Robert R. Gibson , W. N. Brandt , S. C. Gallagher , Paul C. Hewett , Donald P. Schneider

We present a detailed investigation of the variability of 428 C IV and 235 Si IV Broad Absorption Line (BAL) troughs identified in multi-epoch observations of 291 quasars by the Sloan Digital Sky Survey-I/II/III. These observations…

We report the discovery of a Broad Absorption Line (BAL) of \sim 10^4 km s-1 in width in the previously known BL Lac object PKS 0138-097, which we tentatively identified as a Mg II BAL. This is the first detection of a BAL, which is…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-24 Zhang Shaohua , Wang Huiyuan , Zhou Hongyan , Wang Tinggui , Jiang Peng

We have carried out a survey with the Chandra X-ray Observatory of a sample of 10 optically bright broad absorption line (BAL) QSOs. Eight out of ten sources are detected. The 6 brightest X-ray sources have only high ionization BALs…

Astrophysics · Physics 2009-11-06 Paul J. Green , Thomas L. Aldcroft , Smita Mathur , Belinda J. Wilkes , Martin Elvis

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 spectropolarimetry of 19 confirmed and 4 possible bright, southern broad absorption line (BAL) quasars from the European Southern Observatory (ESO) Very Large Telescope (VLT). A wide range of redshifts is covered in the sample…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Michael A. DiPompeo , Michael S. Brotherton , Carlos De Breuck

We present new results on X-ray properties of radio loud broad absorption line (BAL) quasars and focus on broad-band spectral properties of a high ionization BAL (HiBAL) compact steep spectrum (CSS) radio-loud quasar 1045+352. This HiBAL…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 M. Kunert-Bajraszewska , A. Siemiginowska , K. Katarzynski , A. Janiuk

We present the results of EVN+MERLIN VLBI polarization observations of 8 Broad Absorption Line (BAL) quasars at 1.6 GHz, including 4 LoBALs and 4 HiBALs with either steep or flat spectra on VLA scales. Only one steep-spectrum source,…

Astrophysics · Physics 2009-11-13 Y. Liu , D. R. Jiang , T. G. Wang , F. G. Xie

There is a large diversity in the C IV broad absorption line (BAL) profile among BAL quasars (BALQs). We quantify this diversity by exploring the distribution of the C IV BAL properties, FWHM, maximum depth of absorption and its velocity…

Astrophysics of Galaxies · Physics 2015-06-24 Alexei Baskin , Ari Laor , Fred Hamann

Broad absorption lines (BALs) in quasar spectra identify high velocity outflows that might exist in all quasars and could play a major role in feedback to galaxy evolution. The viability of BAL outflows as a feedback mechanism depends on…

Astrophysics of Galaxies · Physics 2015-06-22 Daniel M. Capellupo , Fred Hamann , Tom A. Barlow

We have used data from the Herschel-ATLAS at 250, 350 and 500 \mu m to determine the far-infrared (FIR) properties of 50 Broad Absorption Line Quasars (BAL QSOs). Our sample contains 49 high-ionization BAL QSOs (HiBALs) and 1 low-ionization…