NeVI spectrum

Analysis of HST/COS spectra of the bare C–O stellar core H1504+65 and a high-velocity twin in the Galactic halo

“…This is also favoured by the fact that the total equivalent width of the computed doublet better fits to the strong observed feature than to the weaker observed lines. Another Ne vi multiplet at 1645-1680 Å is much weaker but the wavelengths of the components are well known, (±0.03 Å, Kramida et al 1999) and the strongest components are detectable in the observation.…”

“…The weaker lines might be assigned to the modelled doublet because their spacing of 2.3 Å is similar to that of the Ritz wavelengths (2.6 Å), although the absolute differences (0.9 and 1.2 Å) are about twice the quoted uncertainty of 0.5 Å. Another possibility is that the doublet spacing computed by Kramida et al (1999) is overestimated and indeed unresolvable in the H1504+65 spectrum. The strong feature at 1270.3 Å coincides with the (unresolved) laboratory measurement of Kramida et al (1999) at 1271.8 Å within its 1.5 Å uncertainty.…”

“…According to Kramida et al (1999), they are located at a single observed wavelength (1271.8 ± 1.5 Å) but two (computed) Ritz wavelengths (1270.2/1272.8 ± 0.5 Å) and both components have the same strength. In the H1504+65 spectrum is one strong line at 1270.3 Å plus two nearby, weaker ones with similar strength at 1269.3 and 1271.6 Å.…”

“…Another possibility is that the doublet spacing computed by Kramida et al (1999) is overestimated and indeed unresolvable in the H1504+65 spectrum. The strong feature at 1270.3 Å coincides with the (unresolved) laboratory measurement of Kramida et al (1999) at 1271.8 Å within its 1.5 Å uncertainty. This is also favoured by the fact that the total equivalent width of the computed doublet better fits to the strong observed feature than to the weaker observed lines.…”

1s2s2p23p6L–1s2p33p6P transitions in O IV, F V and Ne VI

“…In his work, fast beam-foil spectra of oxygen were recorded at Liege using grading incidence spectrometers [4,5]. Spectra of fluorine and neon were previously recorded at the University of Lyon and the Argonne National Lab, The 1s2s2p 2 3d 6 L -1s2p 3 3d 6 D, L=F, D, P electric-dipole transitions in O IV, F V and Ne VI have been searched in these spectra, and compared with results of MCHF (with QED and higher-order corrections) and MCDF calculations.…”