Absorption features in the quasar HS 1603 + 3820 II. Distance to the absorber obtained from photoionisation modelling

A. Rózańska, M. Nikołajuk, B. Czerny, A. Dobrzycki, K. Hryniewicz, Jill Bechtold, H. Ebeling

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

We present the photoionisation modelling of the intrinsic absorber in the bright quasar HS 1603 + 3820. We constructed the broad-band spectral energy distribution using the optical/UV/X-ray observations from different instruments as inputs for the photoionisation calculations. The spectra from the Keck telescope show extremely high Civ to Hi ratios, for the first absorber in system A, named A1. This value, together with high column density of Civ ion, place strong constraints on the photoionisation model. We used two photoionisation codes to derive the hydrogen number density at the cloud illuminated surface. By estimating bolometric luminosity of HS 1603 + 3820 using the typical formula for quasars, we calculated the distance to A1. We could find one photoionization solution, by assuming either a constant density cloud (which was modelled using cloudy), or a stratified cloud (which was modelled using titan), as well as the solar abundances. This model explained both the ionic column density of Civ and the high Civ to Hi ratio. The location of A1 is 0.1 pc, and it is situated even closer to the nucleus than the possible location of the Broad Line Region in this object. The upper limit of the distance is sensitive to the adopted covering factor and the carbon abundance. Photoionisation modelling always prefers dense clouds with the number density n0 = 1010 - 1012 cm-3, which explains intrinsic absorption in HS 1603 + 3820. This number density is of the same order as that in the disk atmosphere at the implied distance of A1. Therefore, our results show that the disk wind that escapes from the outermost accretion disk atmosphere can build up dense absorber in quasars.

Original languageEnglish (US)
Pages (from-to)70-78
Number of pages9
JournalNew Astronomy
Volume28
DOIs
StatePublished - 2014

Fingerprint

Photoionization
quasars
photoionization
absorbers
modeling
atmospheres
atmosphere
Titan
spectral energy distribution
Telescopes
accretion disks
escape
Luminance
coverings
estimating
accretion
luminosity
telescopes
hydrogen
broadband

Keywords

  • (Galaxies:) quasars: absorption lines
  • (Galaxies:) quasars: individual (HS 1603 + 3820)
  • Atomic processes
  • Radiative transfer

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics
  • Instrumentation

Cite this

Absorption features in the quasar HS 1603 + 3820 II. Distance to the absorber obtained from photoionisation modelling. / Rózańska, A.; Nikołajuk, M.; Czerny, B.; Dobrzycki, A.; Hryniewicz, K.; Bechtold, Jill; Ebeling, H.

In: New Astronomy, Vol. 28, 2014, p. 70-78.

Research output: Contribution to journalArticle

Rózańska, A. ; Nikołajuk, M. ; Czerny, B. ; Dobrzycki, A. ; Hryniewicz, K. ; Bechtold, Jill ; Ebeling, H. / Absorption features in the quasar HS 1603 + 3820 II. Distance to the absorber obtained from photoionisation modelling. In: New Astronomy. 2014 ; Vol. 28. pp. 70-78.
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