On the Nature of Soft X-Ray Weak Quasi-stellar Objects
TLDR
In this paper, an analysis of C IV absorption in the 55 Boroson & Green QSOs with available C IV data was conducted, and the authors found a remarkably strong correlation between?ox and the C IV equivalent width.Abstract:
Recent studies of quasi-stellar objects (QSOs) with ROSAT suggest the existence of a significant population of soft X-ray weak QSOs (SXW QSOs) where the soft X-ray flux is ~10-30 times smaller than in typical QSOs. Why are these QSOs soft X-ray weak, and what is their relationship to broad absorption line QSOs (BAL QSOs) and X-ray warm absorber QSOs? As a first step in a systematic study of these objects, we establish a well-defined sample of SXW QSOs that includes all ?ox ? -2 QSOs from the Boroson & Green sample of 87 Bright Quasar Survey QSOs. SXW?QSOs comprise ?11% of this optically selected QSO sample, and we find soft X-ray weakness in both radio-quiet and radio-loud QSOs. From an analysis of C IV absorption in the 55 Boroson & Green QSOs with available C IV data, we find a remarkably strong correlation between ?ox and the C IV absorption equivalent width. This correlation suggests that absorption is the primary cause of soft X-ray weakness in QSOs, and it reveals a continuum of absorption properties connecting unabsorbed QSOs, X-ray warm absorber QSOs, SXW QSOs, and BAL QSOs. Many of our SXW QSOs have ultraviolet absorption that is intermediate in strength between that of X-ray warm absorber QSOs and that of BAL QSOs, and their X-ray absorption is also likely to be of intermediate strength. From a practical point of view, our correlation demonstrates that selection by soft X-ray weakness is an effective (80% successful) and observationally inexpensive way to find low-redshift QSOs with strong and interesting ultraviolet absorption. We have also identified several notable differences between the optical emission-line properties of SXW QSOs and those of the other Boroson & Green QSOs. SXW?QSOs show systematically low [O III] luminosities and equivalent widths as well as distinctive H? line profiles. They tend to lie toward the weak [O III] end of Boroson & Green eigenvector 1, as do many low-ionization BAL QSOs. Unabsorbed Seyfert galaxies and QSOs with similar values of eigenvector 1 have been suggested to have extreme values of a primary physical parameter, perhaps mass accretion rate relative to the Eddington rate (/Edd). If these suggestions are correct, it is likely that SXW QSOs also tend to have generally high values of /Edd. Finally, we present and discuss correlations between ?ox and other QSO observables after removal of the SXW QSOs.read more
Citations
More filters
Journal ArticleDOI
Dynamics of Line-driven Disk Winds in Active Galactic Nuclei
TL;DR: In this paper, the authors present the results of axisymmetric time-dependent hydrodynamic calculations of line-driven winds from accretion disks in active galactic nuclei (AGNs).
Journal ArticleDOI
Mass Loss from the Nuclei of Active Galaxies
TL;DR: In this paper, the intrinsic UV and X-ray absorbers of active galaxies were studied with the assistance of monitoring observations and photoionization models to provide constraints on their kinematics] physical conditions.
Journal ArticleDOI
BLACK HOLE MASS AND EDDINGTON RATIO AS DRIVERS FOR THE OBSERVABLE PROPERTIES OF RADIO-LOUD AND RADIO-QUIET QSOs
TL;DR: In this paper, it was shown that both narrow-line Seyfert 1 galaxies and broad absorption line QSOs lie at the high L/LEdd extreme, although these two types of objects are well separated in the PC2 direction.
Journal ArticleDOI
The X-Ray-to-Optical Properties of Optically Selected Active Galaxies over Wide Luminosity and Redshift Ranges
A. T. Steffen,Iskra Strateva,W. N. Brandt,David M. Alexander,Anton M. Koekemoer,Bret D. Lehmer,Donald P. Schneider,Cristian Vignali,Cristian Vignali +8 more
TL;DR: In this article, the strengths of the relationships between l2 keV, αOX, and redshift for optically selected active galactic nuclei (AGNs) were examined.
Journal ArticleDOI
The XMM-Newton view of PG quasars - I. X-ray continuum and absorption
Enrico Piconcelli,E. Jimenez-Bailon,Matteo Guainazzi,Norbert Schartel,P. M. Rodríguez-Pascual,M. Santos-Lleo +5 more
TL;DR: In this paper, the authors present results of a systematic analysis of the XMM-Newton spectra of 40 quasars (QSOs) (z ≤ 1.72) from the Palomar-Green (PG) Bright Quasar Survey sample (MB < −23).
References
More filters
Book
Data Reduction and Error Analysis for the Physical Sciences
TL;DR: In this paper, Monte Carlo techniques are used to fit dependent and independent variables least squares fit to a polynomial least-squares fit to an arbitrary function fitting composite peaks direct application of the maximum likelihood.
Journal ArticleDOI
Data Reduction and Error Analysis for the Physical Sciences.
TL;DR: Numerical methods matrices graphs and tables histograms and graphs computer routines in Pascal and Monte Carlo techniques dependent and independent variables least-squares fit to a polynomial least-square fit to an arbitrary function fitting composite peaks direct application of the maximum likelihood.
Book
The observation and analysis of stellar photospheres
TL;DR: In this paper, the authors present a model of the photosphere of the black body and its radiation, and the measurement of stellar continua, spectral lines, and photospheric pressure.
Journal ArticleDOI
The Dip Test of Unimodality
J. A. Hartigan,P. M. Hartigan +1 more
TL;DR: The dip test as mentioned in this paper measures multimodality in a sample by the maximum difference, over all sample points, between the empirical distribution function, and the unimodal distribution function that minimizes that maximum difference.
Journal ArticleDOI
The Emission-Line Properties of Low-Redshift Quasi-stellar Objects
Todd A. Boroson,Richard F. Green +1 more
TL;DR: In this article, an empirical technique which allows the measurement and subtraction of the many Fe II lines in this region has been developed and applied to these spectra, and a four-dimensional parameterization of the Hβ profile has been combined with optical, radio, and X-ray continuum information from the literature to try to understand how these properties are related.
Related Papers (5)
The Emission-Line Properties of Low-Redshift Quasi-stellar Objects
Todd A. Boroson,Richard F. Green +1 more
Quasar evolution derived from the Palomar bright quasar survey and other complete quasar surveys.
Maarten Schmidt,R. F. Green +1 more
Accretion Disk Winds from Active Galactic Nuclei
The Sloan Digital Sky Survey: Technical summary
Donald G. York,Jennifer Adelman,John E. Anderson,Scott F. Anderson,James Annis,Neta A. Bahcall,J. A. Bakken,Robert H. Barkhouser,Steven Bastian,E. Berman,William N. Boroski,Steve Bracker,Charlie Briegel,John W. Briggs,Jon Brinkmann,Robert J. Brunner,Scott Burles,Larry N. Carey,Michael A. Carr,Francisco J. Castander,Francisco J. Castander,Bing Chen,Patrick L. Colestock,Andrew J. Connolly,James H. Crocker,István Csabai,István Csabai,Paul C. Czarapata,John Eric Davis,Mamoru Doi,Tom Dombeck,Daniel J. Eisenstein,Nancy Ellman,Brian R. Elms,Brian R. Elms,Michael L. Evans,Xiaohui Fan,Glenn R. Federwitz,Larry Fiscelli,Scott D. Friedman,Joshua A. Frieman,Joshua A. Frieman,Masataka Fukugita,Bruce Gillespie,James E. Gunn,Vijay K. Gurbani,Ernst De Haas,M. Haldeman,Frederick H. Harris,Jeffrey J. E. Hayes,Timothy M. Heckman,Gregory S. Hennessy,Robert B. Hindsley,S. Holm,Donald J. Holmgren,Chi Hao Huang,Charles L. Hull,Don Husby,Shin-Ichi Ichikawa,Takashi Ichikawa,Zěljko Ivezić,Stephen M. Kent,Rita S. J. Kim,E. Kinney,Mark A. Klaene,A. N. Kleinman,Scot Kleinman,Gillian R. Knapp,John Korienek,Richard G. Kron,Richard G. Kron,Peter Z. Kunszt,D. Q. Lamb,Brian C. Lee,R. French Leger,Siriluk Limmongkol,Carl Lindenmeyer,Dan Long,Craig Loomis,Jon Loveday,Rich Lucinio,Robert H. Lupton,Bryan Mackinnon,Bryan Mackinnon,Edward J. Mannery,Paul M. Mantsch,Bruce Margon,Peregrine M. McGehee,Timothy A. McKay,Avery Meiksin,Aronne Merelli,David G. Monet,Jeffrey A. Munn,Vijay K. Narayanan,Thomas Nash,Eric H. Neilsen,Rich Neswold,Heidi Jo Newberg,Heidi Jo Newberg,Robert C. Nichol,T. Nicinski,T. Nicinski,Mario Nonino,Norio Okada,Sadanori Okamura,Jeremiah P. Ostriker,Russell Owen,A. George Pauls,John Peoples,R. Peterson,Don Petravick,Jeffrey R. Pier,Adrian Pope,Ruth Pordes,Angela Prosapio,R. Rechenmacher,Thomas R. Quinn,Gordon T. Richards,Michael Richmond,Claudio H. Rivetta,Constance M. Rockosi,Kurt Ruthmansdorfer,Dale Sandford,David J. Schlegel,Donald P. Schneider,Maki Sekiguchi,G. Sergey,Kazuhiro Shimasaku,Walter A. Siegmund,Stephen A. Smee,J. Allyn Smith,S. A. Snedden,Robert Stone,Chris Stoughton,Michael A. Strauss,Christopher W. Stubbs,Mark SubbaRao,Alexander S. Szalay,István Szapudi,Gyula P. Szokoly,Anirudda R. Thakar,Christy Tremonti,Douglas L. Tucker,Alan Uomoto,Daniel E. Vanden Berk,Michael S. Vogeley,Patrick Waddell,Shu I. Wang,Masaru Watanabe,David H. Weinberg,Brian Yanny,Naoki Yasuda +151 more