The Lyman alpha forest towards B2 1225 + 317

Pushpa Khare, R. Srianand, D. G. York, R. Green, D. Welty, Ke Liang Huang, Jill Bechtold

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

We present observations of the Lyman alpha (Ly α) forest towards B2 1225 + 317 taken at a resolution of 18 km s -1. A clean sample of Ly α forest lines is extracted after a careful profile-fitting analysis and the removal of the absorption lines of heavy elements. The sample is analysed for statistical properties. Eighty per cent of the column densities are < 10 14 cm -2. A single power law is inconsistent with the column density distribution and a steepening/break in the distribution is indicated. The average velocity dispersion parameter is 29.4 km s -1. We find 3σ evidence for a correlation between column density and the velocity dispersion parameter. The correlation, however, is mainly the result of narrow lines and weakens to 1.2σ if lines with a velocity dispersion parameter smaller than 20 km s -1 are excluded. An excess of line pairs with velocity separation ≤ 100 km s -1 over the expected number is found.

Original languageEnglish (US)
Pages (from-to)167-180
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Volume285
Issue number1
StatePublished - 1997

Fingerprint

heavy elements
density distribution
power law
profiles
parameter
distribution
analysis
removal

Keywords

  • Intergalactic medium
  • Quasars: absorption lines
  • Quasars: individual: B2 1225 + 317

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Khare, P., Srianand, R., York, D. G., Green, R., Welty, D., Huang, K. L., & Bechtold, J. (1997). The Lyman alpha forest towards B2 1225 + 317. Monthly Notices of the Royal Astronomical Society, 285(1), 167-180.

The Lyman alpha forest towards B2 1225 + 317. / Khare, Pushpa; Srianand, R.; York, D. G.; Green, R.; Welty, D.; Huang, Ke Liang; Bechtold, Jill.

In: Monthly Notices of the Royal Astronomical Society, Vol. 285, No. 1, 1997, p. 167-180.

Research output: Contribution to journalArticle

Khare, P, Srianand, R, York, DG, Green, R, Welty, D, Huang, KL & Bechtold, J 1997, 'The Lyman alpha forest towards B2 1225 + 317', Monthly Notices of the Royal Astronomical Society, vol. 285, no. 1, pp. 167-180.
Khare P, Srianand R, York DG, Green R, Welty D, Huang KL et al. The Lyman alpha forest towards B2 1225 + 317. Monthly Notices of the Royal Astronomical Society. 1997;285(1):167-180.
Khare, Pushpa ; Srianand, R. ; York, D. G. ; Green, R. ; Welty, D. ; Huang, Ke Liang ; Bechtold, Jill. / The Lyman alpha forest towards B2 1225 + 317. In: Monthly Notices of the Royal Astronomical Society. 1997 ; Vol. 285, No. 1. pp. 167-180.
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