The nature of weak Mg II absorbing structures

Nikola Milutinović, Jane R. Rigby, Joseph R. Mashiero, Ryan S. Lynch, Chris Palma, Jane Camilla Charlton

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

We consider geometries and physical models for weak low-ionization absorbers based on the relative incidence of low- and high-ionization systems. We present a survey of weak low-ionization systems in 35 high-resolution HST STIS quasar spectra, sometimes supplemented by Keck HIRES and 7/57 FOS data. We found 16 metal-line systems, with low- and/or high-ionization absorption detected. Weak low-ionization absorbers trace an abundant population of metal-enriched regions. Models show that these systems have a ∼ 10 pc region of higher density gas and a ∼ 1 kpc region that represents a lower density, higher ionization phase. The goal of our survey was to compare systems detected in low- and/or high-ionization gas. All but 1 of the 10 weak low-ionization systems have a related high-ionization phase. In three cases the high-ionization gas has only a single component, kinematically centered on the low-ionization absorption, and the other six cases have additional high-ionization components offset in velocity. The high-ionization absorption in weak low-ionization systems has similar kinematic structure to that in high-ionization only systems. There are just six systems with only a high-ionization phase, as compared to the nine systems with both low- and high-ionization phases. We conclude that filamentary and sheetlike geometries are favored, due to the relatively small observed cross section of high-ionization-only systems. Our statistical arguments suggest that although low-ionization absorbers are not closely associated with luminous galaxies, they arise in their immediate environments within the cosmic web.

Original languageEnglish (US)
Pages (from-to)190-209
Number of pages20
JournalAstrophysical Journal
Volume641
Issue number1 I
DOIs
StatePublished - Apr 10 2006

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ionization
gas ionization
absorbers
gas
geometry
gas density
metal
metals
quasars
kinematics
incidence

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Milutinović, N., Rigby, J. R., Mashiero, J. R., Lynch, R. S., Palma, C., & Charlton, J. C. (2006). The nature of weak Mg II absorbing structures. Astrophysical Journal, 641(1 I), 190-209. https://doi.org/10.1086/500314
Milutinović, Nikola ; Rigby, Jane R. ; Mashiero, Joseph R. ; Lynch, Ryan S. ; Palma, Chris ; Charlton, Jane Camilla. / The nature of weak Mg II absorbing structures. In: Astrophysical Journal. 2006 ; Vol. 641, No. 1 I. pp. 190-209.
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Milutinović, N, Rigby, JR, Mashiero, JR, Lynch, RS, Palma, C & Charlton, JC 2006, 'The nature of weak Mg II absorbing structures', Astrophysical Journal, vol. 641, no. 1 I, pp. 190-209. https://doi.org/10.1086/500314

The nature of weak Mg II absorbing structures. / Milutinović, Nikola; Rigby, Jane R.; Mashiero, Joseph R.; Lynch, Ryan S.; Palma, Chris; Charlton, Jane Camilla.

In: Astrophysical Journal, Vol. 641, No. 1 I, 10.04.2006, p. 190-209.

Research output: Contribution to journalArticle

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AU - Milutinović, Nikola

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Milutinović N, Rigby JR, Mashiero JR, Lynch RS, Palma C, Charlton JC. The nature of weak Mg II absorbing structures. Astrophysical Journal. 2006 Apr 10;641(1 I):190-209. https://doi.org/10.1086/500314