Far‐Ultraviolet Spectroscopy of the Intergalactic and Interstellar Absorption toward 3C 273
- 10 November 2001
- journal article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 561 (2), 573-599
- https://doi.org/10.1086/323408
Abstract
We present Far Ultraviolet Spectroscopic Explorer (FUSE) 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 Ly-beta absorption in 8 of the known intergalactic Ly-alpha absorbers along the sight line with rest-frame equivalent widths greater than 50 mA. 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. We detect multiple H I lines (Ly-beta - Ly-theta) in the 1590 km/s Virgo absorber and estimate log N(H I) = 15.85, ten 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, implies T < 15,000 K. We detect O VI absorption at 1015 km/s at the 2-3 sigma 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 IGM at z=0.12007; this absorber is predominantly ionized and has N(H+)/N(H I) > 4000/Z, where Z is the metallicity. Strong Galactic interstellar O VI is present between -100 and +100 km/s, with an additional high-velocity wing containing about 13% of the total O VI between +100 and +240 km/s. The broad O VI absorption wing likely traces the expulsion of hot gas out of the Galactic disk into the halo. A limit on the amount of diffuse O VI emission present 3.5 arc minutes off the sight line combined with the observed O VI column density toward 3C 273, implies n_e < 0.02 cm^-3 and P/k < 11,500 cm^-3 K for an assumed temperature of 3x10^5 K. (abbreviated version)Comment: 59 pages, 15 figures, aastex condensed format, to appear in the Nov. 10, 2001 issue of the Astrophysical JournaKeywords
This publication has 76 references indexed in Scilit:
- The Extreme-Ultraviolet Excess Emission of the Virgo and A1795 Clusters: Reobservation with in Situ Background MeasurementsThe Astrophysical Journal, 2001
- Observations of 3C273 with the Goddard High Resolution Spectrograph on the Hubble Space Telescope. II.The Astronomical Journal, 1997
- A study of ultraviolet absorption lines through the complete Galactic halo by the analysis of HST faint object spectrograph spectra of active Galactic nuclei, 1The Astrophysical Journal, 1994
- The Hubble Space Telescope quasar absorption line key project. I - First observational results, including Lyman-alpha and Lyman-limit systemsThe Astrophysical Journal Supplement Series, 1993
- Observations of 3C 273 with the Goddard High Resolution Spectrograph on the Hubble Space TelescopeThe Astronomical Journal, 1993
- Probing the Galactic halo along the 3C 273 sight line using IUEThe Astrophysical Journal, 1991
- The Ultraviolet Absorption Spectrum of 3C 273The Astrophysical Journal, 1991
- Radiative magnetized thermal conduction frontsThe Astrophysical Journal, 1990
- Abundances of the elements: Meteoritic and solarGeochimica et Cosmochimica Acta, 1989
- The galactic fountain of high-velocity cloudsThe Astrophysical Journal, 1980