The absorption-line spectrum of GC 1556 + 335 - Ejected or intervening material?

Morris, Simon L.; Weymann, R. J.; Foltz, C. B.; Turnshek, David A.; Shectman, S.; Price, Charles I.; Boroson, Todd A.

doi:10.1086/164663

Cited by 42 publications

(44 citation statements)

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“…Velocity dispersions in the C IV absorption system of a few hundred kilometers per second are often due to small-scale motions of bound objects, while larger velocities usually arise from the large-scale expansion of the universe and the fortuitous orientation of the LOS along an expanding filament. This interpretation avoids the difficulties associated with accounting for systems with velocity extent in excess of 500 km s Ϫ1 in terms of galaxy clusters or clouds orbiting in massive halos at these high redshifts (see also Pettini et al 1983 andMorris et al 1986). …”

Section: Discussionmentioning

confidence: 99%

“…Several features, like the extended component structure of C IV-selected absorption systems, are equally difficult to understand in terms of a stationary cloudlet-in-halo model, as in terms of absorption along lines of sight (LOSs) through known types of local galaxy clusters (Pettini et al 1983;Morris et al 1986;Mo 1994). Instead, going back in time, we should ultimately see the small-scale gas condensations from which instabilities and hierarchical clustering have built up presentday galaxies (Lake 1988;Steidel 1990).…”

Section: Introductionmentioning

confidence: 99%

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C IV Absorption from Galaxies in the Process of Formation

Haehnelt

1996

The Astrophysical Journal

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We investigate the heavy element QSO absorption systems caused by gas condensations at high redshift that evolve into galaxies at the present epoch. Artificial QSO spectra were generated for a variety of lines of sight through regions of the universe simulated with a hydrodynamics code. The C IV and H I absorption features in these spectra closely resemble observed C IV and H I absorption systems if [C/H] 1 Ϫ3 to Ϫ2 is assumed. C IV absorption complexes with multiple-component structure and velocity spreads up to 1600 km s Ϫ1 are found. The broadest systems are caused by lines of sight passing through groups of protogalactic clumps aligned along filamentary structures expanding with the Hubble flow. Typical clumps have a radius of about 5-10 kpc, a baryonic mass of 110 9 M J , and are surrounded by hot gas atmospheres with a radius of about 30 kpc. The temperature of a considerable fraction of the gas does not take the photoionization equilibrium value. This invalidates density and size estimates derived from thermal equilibrium models. Our model may be able to explain both high-ionization multicomponent heavy-element absorbers and damped Ly␣ systems as groups of small protogalactic clumps.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

C IV Absorption from Galaxies in the Process of Formation

Haehnelt

1996

The Astrophysical Journal

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“…It is possible that lowionization AALs, which allow us to locate the absorber via Si II*, select in favor of large absorber-quasar distances. In particular, all of the known AAL systems with these excitedstate lines have distances kpc (e.g., Z10 Tripp, Lu, & Savage 1996 ;Morris et al 1986 ;Sargent, Boksenberg, & Young 1982). Other AALs are known to form much closer to the quasars, possibly within a few parsecs in outÑows similar to the BALs (Hamann et al 1997a(Hamann et al , 1997b.…”

Section: T Oward a Physical Modelmentioning

confidence: 99%

High‐Resolution Keck Spectra of the Associated Absorption Lines in 3C 191

Hamann

Barlow

Chaffee

et al. 2001

ApJ

149

182

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Associated absorption lines (AALs) are valuable probes of the gaseous environments near quasars. Here we discuss high-resolution (6.7 km s~1) spectra of the AALs in the radio-loud quasar 3C 191 (redshift z \ 1.956). The measured AALs have ionizations ranging from Mg I to N V and multicomponent proÐles that are blueshifted by D400 to D1400 km s~1 relative to the quasarÏs broad emission lines. These data yield the following new results : (1) The strengths of excited-state Si II* AALs indicate a density of D300 cm~3 in the Si`gas. (2) If the gas is photoionized, this density implies a distance of D28 kpc from the quasar. Several arguments suggest that all of the lines form at approximately this distance. (3) The characteristic Ñow time from the quasar is thus D3 ] 107 yr. (4) Strong Mg I AALs identify neutral gas with very low ionization parameter and high density. We estimate n HZ 5 ] 104 cm~3 in this region, compared to D15 cm~3 where the N V lines form. (5) The total column density is cm~2 in the neutral gas and cm~2 in the moderately ionized] 1020 regions. These column densities are consistent with 3C 191Ïs strong soft X-ray Ñux and the implied absence of soft X-ray absorption. (6) The total mass in the AAL outÑow is M D 2 ] 109 assuming M _ , a global covering factor (as viewed from the quasar) of D10%. (7) The absorbing gas only partially covers the background light source(s) along our line(s) of sight, requiring absorption in small clouds or Ðlaments less than 0.01 pc across. The ratio implies that the clouds have radial (line-of-sight) N H /n H thicknesses pc. These properties might characterize a subclass of AALs that are physically related [0.2 to quasars but form at large distances. We propose a model for the absorber in which pockets of dense neutral gas are surrounded by larger clouds of generally lower density and higher ionization. This outÑowing material might be leftover from a blowout associated with a nuclear starburst, the onset of quasar activity, or a past broad absorption line (BAL) wind phase.

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“…5). These features arise from ground multiplets that behave approximately as two-level atoms, the level populations being controlled by collisional processes and radiative decays (Bahcall & Wolf 1968;Morris et al 1986;Osterbrock 1989). The strength of the absorption lines from the excited fine-structure levels C  λ1335.7 and Si  λ1264.8 can be directly compared to the resonance transitions C  λ1334.5 and Si  λ1260.4 in order to estimate the electron density needed to populate the upper level.…”

Section: Absorption From Excited Levels: Electron Density and Distancmentioning

confidence: 99%

VLT + UVES spectroscopy of the low-ionization intrinsic absorber in SDSS J001130.56+005550.7

Hutsemékers

Brinkmann²

2004

A&A

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Abstract. We analyse high-resolution VLT+UVES spectra of the low-ionization intrinsic absorber observed in the BAL QSO SDSS J001130.56+005550.7. Two narrow absorption systems at velocities −600 km s −1 and −22 000 km s −1 are detected. The low-velocity system is part of the broad absorption line (BAL), while the high-velocity one is well detached. While most narrow absorption components are only detected in the high-ionization species, the lowest velocity component is detected in both highand low-ionization species, including in the excited Si  and C  lines. From the analysis of doublet lines, we find that the narrow absorption lines at the low-velocity end of the BAL trough are completely saturated but do not reach zero flux, their profiles being dominated by a velocity-dependent covering factor. The covering factor is significantly smaller for Mg  than for Si  and N , which demonstrates the intrinsic nature of absorber. From the analysis of the excited Si  and C  lines in the lowest velocity component, we find an electron density 10 3 cm −3 . Assuming photoionization equilibrium, we derive a distance 20 kpc between the low-ionization region and the quasar core. The correspondence in velocity of the high-and low-ionization features suggests that all these species must be closely associated, hence formed at the same distance of ∼20 kpc, much higher than the distance usually assumed for BAL absorbers.

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The absorption-line spectrum of GC 1556 + 335 - Ejected or intervening material?

Cited by 42 publications

References 0 publications

C IV Absorption from Galaxies in the Process of Formation

C IV Absorption from Galaxies in the Process of Formation

High‐Resolution Keck Spectra of the Associated Absorption Lines in 3C 191

VLT + UVES spectroscopy of the low-ionization intrinsic absorber in SDSS J001130.56+005550.7

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