3s<sup>2</sup>3p-3s3p<sup>2</sup>transitions in S iv

Hibbert, A; Brage, Tomas; Fleming, Janine

doi:10.1046/j.1365-8711.2002.05473.x

Cited by 22 publications

(19 citation statements)

References 22 publications

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“…The calculated Avalues for the main transitions were within a few percent of the intensities of the most accurate previous calculations, by Hibbert et al (2002). The largest difference (about 10%) was found for the 1404.8 Å transition.…”

supporting

confidence: 74%

Density diagnostics derived from the O iv and S iv intercombination lines observed by IRIS

Polito

Zanna

Dudík

et al. 2016

A&A

100

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The intensity of the O iv 2s 2 2p 2 P-2s2p 2 4 P and S iv 3 s 2 3p 2 P-3s 3p 2 4 P intercombination lines around 1400 Å observed with the Interface Region Imaging Spectrograph (IRIS) provide a useful tool to diagnose the electron number density (N e ) in the solar transition region plasma. We measure the electron number density in a variety of solar features observed by IRIS, including an active region (AR) loop, plage and brightening, and the ribbon of the 22-June-2015 M 6.5 class flare. By using the emissivity ratios of O iv and S iv lines, we find that our observations are consistent with the emitting plasma being near isothermal (logT [K] ≈ 5) and iso-density (N e ≈ 10 10.6 cm −3 ) in the AR loop. Moreover, high electron number densities (N e ≈ 10 13 cm −3 ) are obtained during the impulsive phase of the flare by using the S iv line ratio. We note that the S iv lines provide a higher range of density sensitivity than the O iv lines. Finally, we investigate the effects of high densities (N e 10 11 cm −3 ) on the ionization balance. In particular, the fractional ion abundances are found to be shifted towards lower temperatures for high densities compared to the low density case. We also explored the effects of a non-Maxwellian electron distribution on our diagnostic method.

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supporting

confidence: 74%

Density diagnostics derived from the O iv and S iv intercombination lines observed by IRIS

Polito

Zanna

Dudík

et al. 2016

A&A

100

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“…A useful feature of these lines is that the fractional abundance of S iv peaks at a similar ionization parameter to that of the ubiquitous C iv, implying that they arise in similar regions of the outflow . The presence of two excited S iv* transitions with oscillator strengths an order of magnitude apart (Hibbert et al 2002) provides sensitivity to a wide range of optical depths before both troughs become fully saturated.…”

Section: The S IV Column Densitymentioning

confidence: 99%

Bal Phosphorus Abundance and Evidence for Immense Ionic Column Densities in Quasar Outflows: VLT/X-Shooter Observations of Quasar SDSS J1512+1119

Borguet

Edmonds

Arav

et al. 2012

ApJ

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We present spectroscopic analysis of the broad absorption line (BAL) outflow in quasar SDSS J1512+1119. In particular, we focus our attention on a kinematic component in which we identify P v and S iv/S iv* absorption troughs. The shape of the unblended phosphorus doublet troughs and the three S iv/S iv* troughs allow us to obtain reliable column density measurements for these two ions. Photoionization modeling using these column densities and those of He i* constrain the abundance of phosphorus to the range of 0.5-4 times the solar value. The total column density, ionization parameter, and metallicity inferred from the P v and S iv column densities lead to large optical depth values for the common transition observed in BAL outflows. We show that the true C iv optical depth is ∼1000 times greater in the core of the absorption profile than the value deduced from its apparent optical depth.

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“…Expected optical depth for C iv, Si iv, S iv, and C ii lines, from Equation (2), assuming solar abundances (Lodders et al 2003) and normalizing to τ max (C iv) = 10. We used an oscillator strength of 0.05 for S iv λ1063 (Hibbert et al 2002), 0.19 for C iv λ1548, 0.52 for S iv λ1393, and 0.13 for C ii λ1334 (Kurucz & Bell 1995). Ionization fractions were calculated with the photoionization code CLOUDY using a Mathews & Ferland (1987) SED.…”

Section: IVmentioning

confidence: 99%

Bal Outflow Contribution to Agn Feedback: Frequency of S Iv Outflows in the SDSS

Dunn

Arav

Aoki

et al. 2012

ApJ

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We present a study of broad absorption line (BAL) quasar outflows that show S iv λ1063 and S iv* λ1073 troughs. The fractional abundances of S iv and C iv peak at similar value of the ionization parameter, implying that they arise from the same physical component of the outflow. Detection of the S iv* troughs will allow us to determine the distance to this gas with higher resolution and higher signal-to-noise spectra, therefore providing the distance and energetics of the ubiquitous C iv BAL outflows. In our bright sample of 156 SDSS quasars, 14% show C iv and 1.9% S iv troughs, which are consistent with a fainter magnitude sample with twice as many objects. One object in the fainter sample shows evidence of a broad S iv trough without any significant trough present from the excited state line, which implies that this outflow could be at a distance of several kpc. Given the fractions of C iv and S iv, we establish firm limits on the global covering factor on S iv that ranges from 2.8% to 21% (allowing for the k-correction). Comparison of the expected optical depth for these ions with their detected percentage suggests that these species arise from common outflows with a covering factor closer to the latter.

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3s²3p-3s3p²transitions in S iv

Cited by 22 publications

References 22 publications

Density diagnostics derived from the O iv and S iv intercombination lines observed by IRIS

Density diagnostics derived from the O iv and S iv intercombination lines observed by IRIS

Bal Phosphorus Abundance and Evidence for Immense Ionic Column Densities in Quasar Outflows: VLT/X-Shooter Observations of Quasar SDSS J1512+1119

Bal Outflow Contribution to Agn Feedback: Frequency of S Iv Outflows in the SDSS

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3s23p-3s3p2transitions in S iv

Cited by 22 publications

References 22 publications

Density diagnostics derived from the O iv and S iv intercombination lines observed by IRIS

Density diagnostics derived from the O iv and S iv intercombination lines observed by IRIS

Bal Phosphorus Abundance and Evidence for Immense Ionic Column Densities in Quasar Outflows: VLT/X-Shooter Observations of Quasar SDSS J1512+1119

Bal Outflow Contribution to Agn Feedback: Frequency of S Iv Outflows in the SDSS

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3s²3p-3s3p²transitions in S iv