Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· arXiv e-print (arXiv:astro-ph/0108047)
· On-line Data
· References in the article
· Citations to the Article (68) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (29)
· NED Objects (13)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
Far-Ultraviolet Spectroscopy of the Intergalactic and Interstellar Absorption toward 3C 273
Authors:
Sembach, Kenneth R.; Howk, J. Christopher; Savage, Blair D.; Shull, J. Michael; Oegerle, William R.
Affiliation:
AA(; Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218.), AB(; Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218.), AC(; Department of Astronomy, University of Wisconsin, Madison, WI 53706.), AD(; CASA and JILA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309.), AE(; NASA Goddard Space Flight Center, Laboratory for Astronomy and Solar Physics, Code 681, Greenbelt, MD 20771.)
Publication:
The Astrophysical Journal, Volume 561, Issue 2, pp. 573-599. (ApJ Homepage)
Publication Date:
11/2001
Origin:
UCP
ApJ Keywords:
Cosmology: Observations, Galaxy: Halo, Galaxies: Intergalactic Medium, ISM: Abundances, ISM: Molecules, Galaxies: Quasars: Absorption Lines
DOI:
10.1086/323408
Bibliographic Code:
2001ApJ...561..573S

Abstract

We present Far Ultraviolet Spectroscopic Explorer observations of the molecular, neutral atomic, weakly ionized, and highly ionized components of the interstellar and intergalactic material toward the quasar 3C 273. We identify Lyβ absorption in eight of the known intergalactic Lyα absorbers along the sight line with rest-frame equivalent widths Wr(Lyα)>~50 mÅ. Refined estimates of the H I column densities and Doppler parameters (b) of the clouds are presented. We find a range of b~16-46 km s-1. We detect multiple H I lines (Lyβ-Lyθ) in the 1590 km s-1 Virgo absorber and estimate logN(H I)=15.85+/-0.100.08, which is 10 times more H I than in all of the other absorbers along the sight line combined. The Doppler width of this absorber, b~16 km s-1, implies T<~15,000 K. We detect O VI absorption at 1015 km s-1 at the 2-3 σ level that may be associated with hot, X-ray-emitting gas in the Virgo Cluster. We detect weak C III and O VI absorption in the intergalactic medium at z=0.12007; this absorber is predominantly ionized and has N(H+)/N(H I)>=4000Z-1, where Z is the metallicity. Strong Galactic interstellar O VI is present between -100 and 100 km s-1, with an additional high-velocity wing containing about 13% of the total O VI between ~100 and ~240 km s-1. The Galactic O VI, N V, and C IV lines have similar shapes, with roughly constant ratios across the -100 to 100 km s-1 velocity range. The high-velocity O VI wing is not detected in other species. Much of the interstellar high ion absorption probably occurs within a highly fragmented medium within the Loop IV remnant or in the outer cavity walls of the remnant. Multiple hot gas production mechanisms are required. The broad O VI absorption wing likely traces the expulsion of hot gas out of the Galactic disk into the halo. A flux limit of 5.4×10-16 ergs cm-2 s-1 on the amount of diffuse O VI emission present ~3.5′ off the 3C 273 sight line combined with the observed O VI column density toward 3C 273, logN(O VI)=14.73+/-0.04, implies ne<~0.02 cm-3 and p/k<~11,500 cm-3 K for an assumed temperature of 3×105 K. The elemental abundances in the neutral and weakly ionized interstellar clouds are similar to those found for other halo clouds. The warm neutral and warm ionized clouds along the sight line have similar dust-phase abundances, implying that the properties of the dust grains in the two types of clouds are similar. Interstellar H2 absorption is present at ~16 km s-1 at a level of logN(H2)~15.71 but does not trace the main column density concentration along the sight line observed in H I 21 cm emission.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints