Skip to main content
Article thumbnail
Location of Repository

BALQSOs in SDSS: On the absence of Observational Evidence for Ly-α―N V line-locking and a discussion of the physical conditions within BAL outflows

By Christopher Euan Cottis


Broad absorption line quasars show broad blue shifted absorption indicative of high velocity outflowing material. The mechanism responsible for accelerating these outflows is a matter of much debate. In this thesis I investigate the possibility that radiative line driving is responsible for driving the outflows in some objects.\ud Various metrics have been proposed to compile homogeneous samples of BALQSOs. Using a new hybrid algorithm we have compiled a sample of 3552 BALQSOs representing approximately 12.5% of the quasars for which SDSS spectra (from DR5) covering the C IV broad absorption line region are available.\ud From this BALQSO catalogue we have selected the largest sample of objects exhibiting evidence for radiative line driving (the ghost of Ly-α), a feature observed in the BAL troughs of around 1% of BALQSOs.\ud Using this sample we test the criteria purported necessary for ghost-formation in order to confirm whether the identified feature is in fact a ghost. This investigation suggests that the feature observed in the majority of objects arises from the superposition of multiple absorption components, which mimic the appearance of a ghost and unrelated to interactions between N V and Ly-α.\ud Follow up spectroscopic observations of some of the ghost candidate objects taken using the William Herschel Telescope and the Gemini North telescope are presented. The reduction of these data is described in detail. The criteria for ghost formation are tested on the new spectra with similar results.\ud One object whose absorption has undergone significant changes is identified and photo-ionisation models used to provide constraints on the physical conditions within the absorber. These models suggest that the changes are due to an increase in the ionisation parameter and not due to changes in the gas covering fraction. The location and mass outflow rate in this object is consistent with previous estimates in similar systems.\ud The work presented within this thesis does not preclude radiative line driving as a mechanism responsible for high velocity quasar outflows. It does however suggest that the ghost of Ly-α, previously considered the strongest evidence for radiative line driving is rarely observed

Publisher: University of Leicester
Year: 2010
OAI identifier:

Suggested articles


  1. 2002, ‘Spectroscopic target selection in the sloan digital sky survey: The quasar sample’,
  2. 2003a, ‘A catalogue of broad absorption line quasars from the sloan digital sky survey early data release’,
  3. 2003b, ‘Continuum and emission-line properties of broad absorption line quasars’,
  4. 2009a, ‘A catalog of broad absorption line quasars in sloan digital sky survey data release 5’,
  5. (1963). 3c 273 : A star-like object with large red-shift’,
  6. (2006). A catalog of broad absorption line quasars from the sloan digital sky survey third data release’,
  7. (1997). A composite hst spectrum of quasars’,
  8. (2000). A fundamental relation between supermassive black holes and their host galaxies’,
  9. (2003). A high-velocity ionized outflow and xuv photosphere in the narrow emission line quasar pg1211+143’,
  10. (2006). A new sample of broad absorption-line quasars exhibiting the ghost of lyman alpha’,
  11. (2000). A relationship between nuclear black hole mass and galaxy velocity dispersion’,
  12. (2005). A size of ˜1au for the radio source sgr a* at the centre of the milky way’,
  13. (2000). A structure for quasars’,
  14. (1959). A survey of radio sources at a frequency of 159 mc/s.’,
  15. (1991). A two-phase model for the x-ray emission from seyfert galaxies’,
  16. (1972). Accretion disc models for compact x-ray sources’,
  17. (1995). Accretion disk winds from active galactic nuclei’,
  18. (1985). Active galactic nuclei - internal dynamics and formation of emission clouds’,
  19. (2004). Active galactic nucleus emission-line properties versus the eddington ratio’,
  20. (2005). Agn feedback causes downsizing’,
  21. (1974). An atlas of seyfert galaxies’,
  22. (1991). An inhomogeneous reference catalogue of identified intervening heavy element systems in spectra of qsos’,
  23. (1997). An Introduction to Active Galactic Nuclei,
  24. (1999). An unusual “mini-bal” quasar at z=4.59’,
  25. (1992). Anisotropic line emission and the geometry of the broad-line region in active galactic nuclei’,
  26. (1994). Atlas of quasar energy distributions’,
  27. (2010). Baryon acoustic oscillations in the sloan digital sky survey data release 7 galaxy sample’,
  28. (2010). Black hole outflows’,
  29. (2005). Black holes in galaxy mergers: The formation of red elliptical galaxies’,
  30. (2006). Breaking the hierarchy of galaxy formation’,
  31. (1996). Broad absorption line quasars observed by the rosat pspc’,
  32. (2007). Broad absorption line variability in repeat quasar observations from the sloan digital sky survey’,
  33. (1998). Broad emission line variability as a constraint upon the physical conditions within the broad emission line region of ngc 5548’,
  34. (2009). Classifying broad absorption line quasars: Metrics, issues and a new catalogue constructed from sdss dr5’,
  35. (1998). Cloudy 90: Numerical simulation of plasmas and their spectra’,
  36. (1999). Clustering of galaxies in a hierarchical universe - i. methods and results at z=0’,
  37. (1988). cold’ material in non-thermal sources’,
  38. (1991). Comparisons of the emission-line and continuum properties of broad absorption line and normal quasi-stellar objects’,
  39. (2001). Composite quasar spectra from the sloan digital sky survey’,
  40. (2006). Confirming the high velocity outflow in pg 1211+143’,
  41. (1989). Continuum energy distribution of quasars - Shapes and origins’,
  42. (2009). Cosmological parameter constraints from sdss luminous red galaxies: a new treatment of large-scale clustering’,
  43. (2008). Dependence of the broad absorption line quasar fraction on radio luminosity’,
  44. (1998). Discovery of radio-loud broad absorption line quasars using ultraviolet excess and deep radio selection’,
  45. (1994). Disk-driven hydromagnetic winds as a key ingredient of active galactic nuclei unification schemes’,
  46. (2010). Distance to multiple kinematic components of quasar outflows: Very large telescope observations of qso 2359-1241 and sdss j0318-0600’,
  47. (1993). Double troughs in broad absorption line quasars and ly-alpha-n v line-locking’,
  48. (2000). Dynamics of line-driven disk winds in active galactic nuclei’,
  49. (1994). Dynamics, Shielding and Line Formation in Accretion Disk Winds from Active Galactic Nuclei,
  50. (1988). Effects of cold matter in active galactic nuclei - a broad hump in the x-ray spectra’,
  51. (1990). Electronpositron pairs, compton reflection, and the x-ray spectra of active galactic nuclei’,
  52. (2008). Emergence of a quasar outflow’,
  53. (2005). Energy input from quasars regulates the growth and activity of black holes and their host galaxies’,
  54. (2003). Evidence of a high-velocity ionized outflow in a second narrow-line quasar pg 0844+349’,
  55. (1992). Extinction in low-ionization broad absorption line quasi-stellar objects’,
  56. (2002). Heating, conduction, and minimum temperatures in cooling flows’,
  57. (2000). Hierarchical galaxy formation’,
  58. (2002). Hot bubbles from active galactic nuclei as a heat source in cooling-flow clusters’,
  59. (1993). Hst observations of ngc 4395, the least luminous seyfert 1 nucleus - evidence against the starburst hypothesis for broad-lined active galactic nuclei’,
  60. (1999). Hubble space telescope observations of the broad absorption line quasarpg 0946+301’,
  61. (1982). Hydromagnetic flows from accretion discs and the production of radio jets’,
  62. (1990). Imaging spectrophotometry of ionized gas in NGC 1068. I -Kinematics of the narrow-line region’,
  63. (1989). Intermediate resolution spectra of quasars with z of greater than 2’,
  64. (1992). Interstellar dust from the milky way to the magellanic clouds’,
  65. (2002). Intrinsic absorption in the qso first j121442.3+280329’,
  66. (1999). Intrinsic narrow absorption lines in keck hires spectra of a sample of six quasars’,
  67. (2001). Keck hires observations of the qso first j104459.6+365605: Evidence for a large-scale outflow’,
  68. (1992). Magnetic acceleration of broad emission-line clouds in active galactic nuclei’,
  69. (2009). Mass outflow in the seyfert 1 galaxy ngc 5548’,
  70. (1997). Metal abundances and ionization in quasar intrinsic absorbers’,
  71. (1988). Mg ii absorption in the spectra of high and low redshift qsos’,
  72. (1994). Modelling the double-trough structure observed in broad absorption line qsos using radiative acceleration’,
  73. (1991). Multidirectional views of the active nucleus of ngc 1068’,
  74. (1999). Multiple velocity components in the c iv absorption line of ngc 5548’,
  75. (1943). Nuclear emission in spiral nebulae.’,
  76. (1982). Obscuration and the various kinds of seyfert galaxies’,
  77. (1978). Observational model of the ionized gas in seyfert and radio-galaxy nuclei’,
  78. (2008). On the absorption of x-ray bright broad absorption line quasars’,
  79. (1993). On the nature of rapid x-ray variability in active galactic nuclei’,
  80. (1986). On the origin of some qso absorption lines’,
  81. (1978). Physical processes in the interstellar medium,
  82. (1999). Polarization of broad absorption line qsos. i. a spectropolarimetric atlas’,
  83. (1974). Properties of black holes relevant to their observation’,
  84. (2000). Properties of radio-selected broad absorption line quasars from the first bright quasar survey’,
  85. (1984). Properties of the broad absorption-line qsos’,
  86. (2009). Quantifying the fast outflow in the luminous seyfert galaxy pg1211+143’,
  87. (2001). Radiation pressure acceleration by x-rays in active galactic nuclei’,
  88. (1975). Radiation-driven winds in of stars’,
  89. (1994). Radiative acceleration in outflows from broad absorption line quasi-stellar objects. ii. wind models’,
  90. (1995). Radiative acceleration of gas in quasars’,
  91. (1993). Radio-loud agn and the extragalactic gamma-ray background’,
  92. (1986). Rapid x-ray variability of the seyfert galaxy mcg-6-30-15’,
  93. (1997). Reverberation mapping and the physics of active galactic nuclei,
  94. (1993). Reverberation mapping of active galactic nuclei’,
  95. (2000). Reverberation measurements for 17 quasars and the size-mass-luminosity relations in active galactic nuclei’,
  96. (2010). Searching for the signature of radiative line driving: on the absence of Lyα-NV line-locking features in a large sample of BALQSOs’,
  97. (2003). Spectropolarimetry and the geometry of type 1 seyfert nuclei,
  98. (1985). Spectropolarimetry and the nature of ngc 1068’,
  99. (2006). Spectropolarimetry of pks 0040-005 and the orientation of broad absorption line quasars’,
  100. (1983). Spectroscopic evidence for activity in the nuclei of normal spiral galaxies’,
  101. (1984). Studies of broad emission line profiles in qso. i - observed, high-resolution profiles’,
  102. (2004). Supermassive black holes in active galactic nuclei. ii. calibration of the black hole massvelocity dispersion relationship for active galactic nuclei’,
  103. (2001). The 2df galaxy redshift survey: near-infrared galaxy luminosity functions’,
  104. (1991). The analysis of apparent optical depth profiles for interstellar absorption lines’,
  105. (1999). The black hole-to-bulge mass relation in active galactic nuclei’,
  106. (2007). The cosmic evolution survey (cosmos): Overview’,
  107. (2004). The cosmological evolution of quasar black hole masses’,
  108. (2009). The dusty nuclear torus in ngc 4151: Constraints from gemini near-infrared integral field spectrograph observations’,
  109. (2002). The effects of inhomogeneous absorbers on the formation of intrinsic quasar absorption lines’,
  110. (1994). The einstein database of ipc x-ray observations of optically selected and radio-selected quasars, 1.’,
  111. (2006). The feedback-regulated growth of black holes and bulges through gas accretion and starbursts in cluster central dominant galaxies’,
  112. (1997). The First Radio-loud Broad Absorption Line QSO and Evidence for a Hidden Population of Quasars’,
  113. (1993). The first ultraviolet spectropolarimetric study of ngc 1068’,
  114. (1990). The fuelling of active galactic nuclei’,
  115. (1982). The importance of atmospheric differential refraction in spectrophotometry’,
  116. (2008). The intrinsic fraction of broad-absorption line quasars’,
  117. (1988). The iraf ccd reduction package - ccdred,
  118. (1974). The morphology of extragalactic radio sources of high and low luminosity’,
  119. (1999). The polarization of broad absorption line qsos’,
  120. (2003). The position, motion, and mass of sgr a*’,
  121. (2010). The quasar outflow contribution to agn feedback: Vlt measurements of sdss j0318-0600’,
  122. (1992). The radio properties of the broad-absorption-line qsos’,
  123. (2005). The relationship between luminosity and broad-line region size in active galactic nuclei’,
  124. (1994). The role of radiative acceleration in outflows from broad absorption line qsos. i. comparison with o star winds’,
  125. (2005). The sloan digital sky survey quasar catalog. iii. third data release’,
  126. (2007). The sloan digital sky survey quasar catalog. iv. fifth data release’,
  127. (2000). The sloan digital sky survey: Technical summary’,
  128. (1998). The sloan digital sky survey’,
  129. (2002). The slope of the black hole mass versus velocity dispersion correlation’,
  130. (2001). The spectrum of bal qso q1303+308: intrinsic variability and line-locking stability’,
  131. (1988). The ultraviolet continuum of quasars - part two -continuum variability’,
  132. (1998). The very highly ionized broad absorption line system of the qso sbs 1542+541’,
  133. (2007). Theory of winds in agns,
  134. (1993). Time variability in the gamma-ray emission of 3c 279’,
  135. (1996). Time variability of broad absorption-line QSO’s,
  136. (1995). Unified schemes for radio-loud active galactic nuclei’,
  137. (2002). Unusual broad absorption line quasars from the sloan digital sky survey’,
  138. (2004). Variability tests for intrinsic absorption lines in quasar spectra’,
  139. (1993). Variable c iv absorption in the seyfert galaxy ngc 5548: A connection to broad absorption line quasi-stellar objects?’,
  140. (1993). Velocity shifts and emission line studies of redshift 2 qsos,
  141. (1999). What determines the depth of broad absorption lines? keck hires observations of balqso 1603+3002’,
  142. (1987). What heats the hot phase in active nuclei?’,
  143. (2009). X-ray insights into the physics of mini-bal quasar outflows’,
  144. (1991). X-ray reflection from cold matter in active galactic nuclei and x-ray binaries’,
  145. (2005). X-ray/ultraviolet campaign on the mrk 279 agn outflow: Constraining inhomogeneous absorber models’,

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.