An astrophysical oscillator strength for the S II 94.7-nm resonance line and S abundances in DLAs

Bonifacio, P.; Caffau, E.; Centurión, M.; Molaro, P.; Vladilo, G.

doi:10.1046/j.1365-8711.2001.04495.x

Cited by 5 publications

(6 citation statements)

References 12 publications

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“…However, similar inconsistencies in the relative abundance of α-elements have been found in other high-redshift absorbers, too (e.g. Bonifacio et al 2001;Prochaska & Wolfe 2002;Fathivavsari et al 2013). We note that the large range in the above listed ratios originates in the very weak sulphur absorption, which is below the detection limit in most of the absorption components.…”

Section: Abundances From Ion Ratiossupporting

confidence: 75%

“…Abundance ratios that cannot be explained by current nucleosynthetic theories have also been found by other groups, e.g. by Fathivavsari et al (2013), who find sulphur being overabundant compared to oxygen in a sub-DLA, by Bonifacio et al (2001), who find sulphur being overabundant compared to oxygen, silicon, and iron even though [S/H] = −1.04 in the considered DLA, and by Lehner et al (2008).…”

Section: S II Absorptionsupporting

confidence: 74%

Section: Abundances From Ion Ratiossupporting

confidence: 64%

“…As has been pointed out in Sect. 4.7, peculiar sulphur abundances have also been found by Bonifacio et al (2001), and Fathivavsari et al (2013) have derived abundances of α-elements not being in line with each other in sub-DLA systems. Other detailed studies of multi-component absorbers at high redshift provide further evidence of significant discrepancies between a standard SN Type II enrichment pattern and measured gas-phase abundances in individual absorption components.…”

Section: Relevance To Other Studiesmentioning

confidence: 85%

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VLT/UVES observations of peculiarαabundances in a sub-DLA atz≈ 1.8 towards the quasar B1101−26

Fox¹,

Richter²,

Fechner³

2014

A&A

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We present a detailed analysis of chemical abundances in a sub-damped Lyman α absorber at z = 1.839 towards the quasar B1101−26, based on a very-high-resolution (R ∼ 75 000) and high-signal-to-noise (S /N > 100) spectrum observed with the UV Visual Echelle spectrograph (UVES) installed on the ESO Very Large Telescope (VLT). The absorption line profiles are resolved into a maximum of eleven velocity components spanning a rest-frame velocity range of ≈200 km s −1 . Detected ions include C , We calculate detailed photoionisation models for two subcomponents with Cloudy, and can rule out that ionisation effects alone are responsible for the high S/O ratio. We instead speculate that the high S/O ratio is caused by the combination of several effects, such as specific ionisation conditions in multi-phase gas, unusual relative abundances of heavy elements, and/or dust depletion in a local gas environment that is not well mixed and/or that might be related to star-formation activity in the host galaxy. We discuss the implications of our findings for the interpretation of α-element abundances in metal absorbers at high redshift.

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Section: Abundances From Ion Ratiossupporting

confidence: 75%

Section: S II Absorptionsupporting

confidence: 74%

Section: Abundances From Ion Ratiossupporting

confidence: 64%

Section: Relevance To Other Studiesmentioning

confidence: 85%

See 2 more Smart Citations

VLT/UVES observations of peculiarαabundances in a sub-DLA atz≈ 1.8 towards the quasar B1101−26

Fox¹,

Richter²,

Fechner³

2014

A&A

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“…It can be seen that apart from one DLA with an extremely large [S/Fe], there is no strong trend for systems with lower [S/Si] (supposedly less dusty) to show lower [S/Fe], suggesting that low S/Fe ratios are not strongly effected by dust. Indeed, the large S abundance measured in Q0307−49 might be due to Lyα blending (Bonifacio et al 2001) and must be considered with caution. Therefore, low S/Fe is not obviously correlated with low dust content, at least not to the accuracy we can Fig.…”

Section: How Dust And/or Ionization Might Affect the Observed Ratiosmentioning

confidence: 99%

Distinct abundance patterns in multiple damped Lyαgalaxies: Evidence for truncated star formation?

López

Ellison

2003

A&A

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Abstract. Following our previous work on metal abundances of a double damped Lyα system with a line-of-sight separation ∼2000 km s −1 (Ellison & Lopez 2001), we present VLT UVES abundances of 3 new systems spanning a total of ∼6000 km s −1 at z ∼ 2.5 toward the southern QSO CTQ247. These abundances are supplemented with echelle observations of another "double" damped Lyα system in the literature. We propose a definition in terms of velocity shift of the sub-class "multiple damped Lyα system", which is motivated by its possible connection with large-scale structure. We find that the abundance ratio [S/Fe] is systematically low in multiple systems compared with single systems, and with a small scatter. The same behavior is found in 2 more single DLA systems taken from the literature that show evidence of belonging to a galaxy group. Although [Si/Fe] ratios are also generally lower in multiple DLAs than in single DLAs, the effect is less striking since the scatter is larger and there are a number of low [Si/Fe] DLAs in the literature. We suggest that this can be explained with a combination of detection bias and, to a lesser extent, the scatter in ionization corrections for different absorbers. We investigate whether consistently low α/Fe ratios could be due to dust depletion or ionization corrections and find that the former effect would emphasize the observed trend of low α/Fe in multiple systems even further. Ionization may have a minor effect in some cases, but at a level that would not change our conclusions. We thus conclude that the low α/Fe ratios in multiple DLAs have a nucleosynthetic origin and suggest that they could be explained by reduced star formation in multiple damped Lyα systems, possibly due to environmental effects. There seems to be independent evidence for this scenario from the mild odd-even effect and from the relatively high N/α ratios we observe in these multiple systems.

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Early stages of nitrogen enrichment in galaxies: Clues from measurements in damped Lyman αsystems

Centurión

Molaro

Vladilo

et al. 2003

A&A

Self Cite

115

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Abstract. We present 4 new measurements of nitrogen abundances and one upper limit in damped Ly α absorbers (DLAs) obtained by means of high resolution (FWHM ≃ 7 km s −1 ) UVES/VLT spectra. In addition to these measurements we have compiled data from all DLAs with measurements of nitrogen and α-capture elements (O, S or Si) available in the literature, including all HIRES/Keck and UVES/VLT data for a total of 33 systems, i.e. the largest sample investigated so far. We find that [N/α]

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An astrophysical oscillator strength for the S II 94.7-nm resonance line and S abundances in DLAs

Cited by 5 publications

References 12 publications

VLT/UVES observations of peculiarαabundances in a sub-DLA atz≈ 1.8 towards the quasar B1101−26

VLT/UVES observations of peculiarαabundances in a sub-DLA atz≈ 1.8 towards the quasar B1101−26

Distinct abundance patterns in multiple damped Lyαgalaxies: Evidence for truncated star formation?

Early stages of nitrogen enrichment in galaxies: Clues from measurements in damped Lyman αsystems

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