The L[CLC]y[/CLC]α Forest of the Quasar in the Hubble Deep Field South

Savaglio, S.; Ferguson, Henry C.; Brown, Thomas M.; Espey, B. R.; Sahu, Kailash C.; Baum, Stefi A.; Carollo, C. M.; Kaiser, M. E.; Stiavelli, M.; Williams, Robert E.; Wilson, Jennifer C. H.

doi:10.1086/311963

Cited by 34 publications

(43 citation statements)

References 9 publications

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“…The low redshift bin of the C iv forest covers the wavelength region where the 2 The STIS spectrum is taken from http://www.stsci.edu/ftp/ observing/hdf/hdfsouth/hdfs.html (Savaglio et al 1999). different CCDs from two dichroic settings were used at ∼4780 Å (or z ∼ 2.1).…”

Section: Data and Voigt Profile Fittingmentioning

confidence: 99%

“…4-6 for two different column density ranges: log N H i = [14,17], and [13.1, 14]. Data compiled from the literature are indicated in the figures: Hu et al (1995), Lu et al (1996), Kim et al (1997), Kirkman & Tytler (1997), Weymann et al (1998), Savaglio et al (1999), Kim et al (2001), Sembach et al (2004), Williger et al (2006), Aracil et al (2006) 3 , Janknecht et al (2006) 4 , Lehner et al (2007) and Williger et al (2010). To be consistent with our definition of the proximity effect zone, we applied the same 4000 km s −1 exclusion within the quasar's Lyα emission line for all the literature data, whenever the line lists from the literature include all the Lyα lines below the Lyα emission line of the quasar.…”

Section: Absorber Number Density Evolution Dn/dzmentioning

confidence: 99%

“…The literature data used in the combined line list include all the quasar sightlines shown in Figs. 4 and 5, except the HST/FOS Weymann et al (1998) data, the Williger et al (2006) data and the Savaglio et al (1999) data. The HST/FOS data was excluded since they were based on the equivalent width measurements, while the Williger et al (2006) data suffered from noise features.…”

Section: Absorber Number Density Evolution Dn/dzmentioning

confidence: 99%

“…The HST/FOS data was excluded since they were based on the equivalent width measurements, while the Williger et al (2006) data suffered from noise features. The Savaglio et al (1999) result is from a single sightline and provides the only data point besides the Janknecht et al (2006) data at z ∼ 1. Although the Janknecht et al (2006) data also suffer from noise, they were from 9 sightlines.…”

Section: Absorber Number Density Evolution Dn/dzmentioning

confidence: 99%

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The evolution of H i and C iv quasar absorption line systems at 1.9 <z< 3.2

Kim

Partl

Carswell

et al. 2013

A&A

104

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We have investigated the distribution and evolution of ∼3100 intergalactic neutral hydrogen (H i) absorbers with H i column densities log N H i = [12.75, 17.0] at 1.9 < z < 3.2, using 18 high resolution, high signal-to-noise quasar spectra obtained from the ESO VLT/UVES archive. We used two sets of Voigt profile fitting analysis, one including all the available high-order Lyman lines to obtain reliable H i column densities of saturated lines, and another using only the Lyα transition. There is no significant difference between the Lyα-only fit and the high-order Lyman fit results. Combining our Lyα-only fit results at 1.7 < z < 3.6 with high-quality literature data, the mean number density at 0 < z < 4 is not well described by a single power law and strongly suggests that its evolution slows down at z ≤ 1.5 at the high and low column density ranges. We also divided our entire H i absorbers at 1.9 < z < 3.2 into two samples, the unenriched forest and the C iv-enriched forest, depending on whether H i lines are associated with C iv at log N C iv ≥ 12.2 within a given velocity range. The entire H i column density distribution function (CDDF) can be described as the combination of these two well-characterised populations which overlap at log N H i ∼ 15. At log N H i ≤ 15, the unenriched forest dominates, showing a similar power-law distribution to the entire forest. The C iv-enriched forest dominates at log N H i ≥ 15, with its distribution function as ∝N ∼−1.45. However, it starts to flatten out at lower N H i , since the enriched forest fraction decreases with decreasing N H i . The deviation from the power law at log N H i = [14, 17] shown in the CDDF for the entire H i sample is a result of combining two different H i populations with a different CDDF shape. The total H i mass density relative to the critical density is Ω H i ∼ 1.6 × 10 −6 h −1 , where the enriched forest accounts for ∼40% of Ω H i .

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Section: Data and Voigt Profile Fittingmentioning

confidence: 99%

Section: Absorber Number Density Evolution Dn/dzmentioning

confidence: 99%

Section: Absorber Number Density Evolution Dn/dzmentioning

confidence: 99%

Section: Absorber Number Density Evolution Dn/dzmentioning

confidence: 99%

See 2 more Smart Citations

The evolution of H i and C iv quasar absorption line systems at 1.9 <z< 3.2

Kim

Partl

Carswell

et al. 2013

A&A

104

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“…Therefore, we restricted our analysis to N H i = 10 12.5−16.0 cm −2 . We included all the forest lines regardless of the existence of associated metals because results from the HST observations are in general based on the equivalent width of the forest lines, not on the existence of metals (Weymann et al 1998;Savaglio et al 1999;Penton et al 2000). In addition, the detection of metal lines in the forest at N H i ≥ 10 14 cm −2 and at z ∼ 3 make it unclear whether there is a spread in the metallicity in the Lyα forest or if there exists two different populations, such as a metal-free forest and a metal-contaminated Lyα forest (Songaila 1998;Ellison et al 1999).…”

Section: The Voigt Profile Fittingmentioning

confidence: 99%

The Lyαforest at $\mathsf{1.5 < {\vec z} < 4}$

Kim¹,

Cristiani

D’Odorico³

2001

A&A

119

191

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Abstract. Using high resolution (R ∼ 45 000), high S/N (∼20-50) VLT/UVES data, we have analyzed the Lyα forest of 3 QSOs in the neutral hydrogen (H i) column density range NH i = 10 12.5−16 cm −2 at 1.5 < z < 2.4. We combined our results with similar high-resolution, high S/N data in the literature at z > 2.4 to study the redshift evolution of the Lyα forest at 1.5 < z < 4. We have applied two types of analysis: the traditional Voigt profile fitting and statistics on the transmitted flux. The results from both analyses are in good agreement: 1. The differential column density distribution function, f (NH i), of the Lyα forest shows little evolution in the column density range NH i = 10 12.5−14 cm −2 , f (NH i) ∝ N −β H i , with β ∼ 1.4-1.5 at 1.5 < z < 4 and with a possible increase of β to β ∼ 1.7 at z < 1.8. A flattening of the power law slope at lower column densities at higher z can be attributed to more severe line blending. A deficiency of lines with NH i > 10 14 cm −2 is more noticeable at lower z than at higher z. The one-point function and the two-point function of the flux confirm that strong lines do evolve faster than weak lines; 2. The line number density per unit redshift, dn/dz, at NH i = 10 13.64−16 cm −2 is well fitted by a single power law, dn/dz ∝ (1 + z) 2.19±0.27 , at 1.5 < z < 4. In combination with the HST results from the HST QSO absorption line key project, the present data indicate that a flattening in the number density evolution occurs at z ∼ 1.2. The line counts as a function of the filling factor at the transmitted flux F in the range 0 < F < 0.9 are constant in the interval 1.5 < z < 4. This suggests that the Hubble expansion is the main drive governing the forest evolution at z > 1.5 and that the metagalactic UV background changes more slowly than a QSO-dominated background at z < 2; 3. The observed cutoff Doppler parameter at the fixed column density NH i = 10 13.5 cm −2 , bc,13.5, shows a weak increase with decreasing z, with a possible local bc,13.5 maximum at z ∼ 2.9; 4. The two-point velocity correlation function and the step optical depth correlation function show that the clustering strength increases as z decreases; 5. The evolution of the mean H i opacity, τ H i, is well approximated by an empirical power law, τ H i ∝ (1+z) 3.34±0.17 , at 1.5 < z < 4; 6. The baryon density, Ω b , derived both from the mean H i opacity and from the one-point function of the flux is consistent with the hypothesis that most baryons (over 90%) reside in the forest at 1.5 < z < 4, with little change in the contribution to the density, Ω, as a function of z.

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