Science-advisor
REGISTER info/FAQ
Login
username
password
     
forgot password?
register here
 
Research articles
  search articles
  reviews guidelines
  reviews
  articles index
My Pages
my alerts
  my messages
  my reviews
  my favorites
 
 
Stat
Members: 3643
Articles: 2'487'895
Articles rated: 2609

28 March 2024
 
  » arxiv » astro-ph/0003277

 Article overview


Intervening O VI Quasar Absorption Systems at Low Redshift: A Significant Baryon Reservoir
T.M. Tripp ; B.D. Savage ; E.B. Jenkins ;
Date 20 Mar 2000
Journal Ap.J. Letters, 534, L1-L5 (May 1, 2000)
Subject astro-ph
AffiliationPrinceton), B.D. Savage (Wisconsin), E.B. Jenkins (Princeton
AbstractFUV echelle spectroscopy of the radio-quiet QSO H1821+643 (z = 0.297), obtained with the Space Telescope Imaging Spectrograph (STIS) at 7 km/s resolution, reveals 4 definite O VI absorption line systems and one probable O VI absorber at 0.15 < z(abs) < 0.27. The four definite O VI absorbers are located near galaxies and are highly displaced from the quasar in redshift; these are likely intervening systems unrelated to the background QSO. In the case of the strong O VI system at z(abs) = 0.22497, multiple components are detected in Si III and O VI as well as H I Lyman series lines, and the differing component velocity centroids and b-values firmly establish that this is a multiphase absorption system. A weak O VI absorber is detected at z(abs) = 0.22637, i.e., offset by ~340 km/s from the z(abs) = 0.22497 system. Lya absorption is detected at z(abs) = 0.22613, but no Lya absorption is significantly detected at 0.22637. Other weak O VI absorbers at z(abs) = 0.24531 and 0.26659 and the probable O VI system at 0.21326 have widely diverse O VI/H I column density ratios with N(O VI)/N(H I) ranging from <=0.14+/-0.03 to 5.2+/-1.2. The number density of O VI absorbers with rest equivalent width > 30 mA in the H1821+643 spectrum is remarkably high, dN/dz ~48, with a high (90%) confidence that it is greater than 17. We conservatively estimate that the cosmological mass density of the O VI systems Omega_b(O VI) > 0.0008/h_75. With an assumed metallicity of 1/10 solar and a conservative assumption that the fraction of oxygen in the O VI ionization stage is 0.2, we obtain Omega_b(O VI) > 0.004/h_75. This is comparable to the combined cosmological mass density of stars and cool gas in galaxies and X-ray emitting gas in galaxy clusters at low redshift.
Source arXiv, astro-ph/0003277
Services Forum | Review | PDF | Favorites   
 
Visitor rating: did you like this article? no 1   2   3   4   5   yes

No review found.
 Did you like this article?

This article or document is ...
important:
of broad interest:
readable:
new:
correct:
Global appreciation:

  Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.

browser claudebot






ScienXe.org
» my Online CV
» Free


News, job offers and information for researchers and scientists:
home  |  contact  |  terms of use  |  sitemap
Copyright © 2005-2024 - Scimetrica