The UV spectrum of HS 1700+6416. I. Predicting the metal line content of the far UV spectrum

  title={The UV spectrum of HS 1700+6416. I. Predicting the metal line content of the far UV spectrum},
  author={Cora Fechner and Dieter Reimers and Antoinette Songaila and Robert A. Simcoe and Michael Rauch and Wallace L. W. Sargent},
  journal={Astronomy and Astrophysics},
Aims. In preparation of a study of the $\ion{He}{ii}$/$\ion{H}{i}$ ratio towards the bright QSO HS 1700+6416, we predict the metal line content of the far-UV spectral range by modelling 18 metal absorption line systems with redshifts $0.2 Methods. For that purpose, we investigate the spectral energy distribution of the metagalactic ionizing radiation field. Simple photoionization models based on 8 different shapes of the ionizing background are tested for each system. The adopted energy… 
The UV spectrum of HS 1700+6416 - II. FUSE observations of the He II Lyman alpha forest
Aims. We present the far-UV spectrum of the quasar HS 1700+6416 taken with FUSE. This QSO provides the second line of sight with the He ii absorption resolved into a Lyα forest structure. Since HS
Spectral shape of the UV ionizing background and He II absorption at redshifts 1.8 $<$ z $<$ 2.9
Aims. The shape of the UV ionizing background is reconstructed from optically thin metal absorption-line systems identified in spectra of HE 2347–4342, Q 1157+3143, and HS 1700+6416 in the redshift
Reconstructing the intergalactic UV background with QSO absorption lines
We present a new approach to observationally constraining the spectral energy distribution of the intergalactic UV background by studying metal absorption systems. We study single-component metal
Fluctuations of the intergalactic ionization field at redshift z ~ 2
Aims. To probe the spectral energy distribution (SED) of the ionizing background radiation at z 2 and to specify the sources contributing to the intergalactic radiation field. Methods. The spectrum
The nature of NV absorbers at high redshift
Aims. We present a study of N v absorption systems at 1.5 z 2.5 in the spectra of 19 QSOs, based on data obtained with the VLT/UVES instrument. Our analysis includes both the absorbers arising from
The reionization epoch of singly ionized helium (He II) is believed to start at redshifts z {approx} 3.5-4 and be nearly complete by z {approx_equal} 2.7. We explore the post-reionization epoch with
The HeII Lyman alpha forest and the thermal state of the IGM
Aims. Recent analyses of the intergalactic UV background by means of the Hell Lya forest assume that Hell and H absorption features have the same line widths. We omit this assumption to investigate
Fluctuations of the intergalactic UV background towards two lines of sight
Aims. We present a reanalysis of the He II Lyα absorption towards the quasars HS 1700+6416 and HE 2347-4342 using new high S/N, optical observations. Methods. An alternative analysis method is
The baryon density at z = 0.9-1.9. Tracing the warm-hot intergalactic medium with broad Lyman α absorption
Aims. We present an analysis of the Lyman a forests of five quasar spectra in the near UV. Properties of the intergalactic medium (IGM) at an intermediate redshift interval (0.9 ≤ z ≤1.9) are
Cosmological radiative transfer and the lonisation of the integalactic medium
Gravitational instability during the evolution of the Universe formed a large scale filamentary structure, known as the cosmic web. Baryons embedded in this cosmic web constitute the intergalactic


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THE intrinsic extreme ultraviolet (EUV) spectrum of quasars, in which spectral lines of He and CNO ions should appear, is in most cases strongly absorbed by the hydrogen Lyman continuum of
A Study of the Reionization History of Intergalactic Helium with FUSE and the Very Large Telescope
We obtained high-resolution Far Ultraviolet Spectroscopic Explorer (FUSE; R ~ 20,000) and Very Large Telescope (VLT; R ~ 45,000) spectra of the quasar HE 2347-4342 in order to study the properties of
Extremely metal-poor Lyman limit system at $\mathsf{{\vec z}_{abs} = 2.917}$ toward the quasar HE 0940–1050
We report on detailed Monte Carlo inversion analysis of the Lyman limit system observed at z a b s = 2.917 in the VLT/UVES spectrum of the quasar HE 0940-1050. Metal absorption lines of carbon and
Resolving the Structure of Ionized Helium in the Intergalactic Medium with the Far Ultraviolet Spectroscopic Explorer
The presence of He ii Lyα absorbers with no H icounterparts indicates that structure is present even in low-density regions, consistent with theoretical predictions of structure formation through gravitational instability.
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Using new Nubble Space Telescope Faint Object Spectrograph, the New Technology Telescope ESO Multi Mode Instrument, and Keck HIRES spectra of the gravitationally lensed double QSO HE 1104-1805 AB
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We report the cumulative results of an ongoing near-infrared search for redshifted Hα emission from normal galaxies at z > 2. An infrared search reduces the bias due to reddening. Using narrowband
The High-Redshift He II Gunn-Peterson Effect: Implications and Future Prospects
Absorption due to He II Lyα has now been detected at low resolution in the spectra of four quasars between redshifts z = 2.74 and z = 3.29. We assess these observations, giving particular attention
A Uniform Analysis of the Lyα Forest at z = 0-5. II. Measuring the Mean Intensity of the Extragalactic Ionizing Background Using the Proximity Effect
Moderate-resolution data for 40 quasi-stellar objects (QSOs) at z ≈ 2 were combined with spectra of comparable resolution of 59 QSOs with redshifts greater than 1.7 found in the literature to form a
Radiative Transfer in a Clumpy Universe. II. The Ultraviolet Extragalactic Background
We present a detailed calculation of the propagation of AGN-like ionizing radiation through the intergalactic space. We model the ionization state of absorbing clouds, and show that the universe will
HE 0141-3932: A bright QSO with an unusual emission line spectrum and associated absorption
HE 0141−3932 (zem = 1.80) is a bright blue radio-quite quasar with an unusually weak Lyα emission line. Large redshift differences (∆z = 0.05) are observed between high ionization and low ionization