| 1. |
- Wang, Kai, et al.
(författare)
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Extended calculations of energy levels, radiative properties, A(J), B-J hyperfine interaction constants, and Lande g(J)-factors for nitrogen-like Ge XXVI
- 2018
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Pergamon Press. - 0022-4073 .- 1879-1352. ; 208, s. 134-151
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Tidskriftsartikel (refereegranskat)abstract
- Employing two state-of-the-art methods, multiconfiguration Dirac-Hartree-Fock and second-order many body perturbation theory, highly accurate calculations are performed for the lowest 272 fine -structure levels arising from the 2s(2)2p(3), 2s(2)p(4), 2p(5), 2s(2)2p(2)3l (l = s, p, d), 2s2p(3)3l (l = s, p, d), and 2p(4)3l (l = s, p. d) configurations in nitrogen-like Ge XXVI. Complete and consistent atomic data, including excitation energies, lifetimes, wavelengths, hyperfine structures, Lande g(J)-factors, and E1, E2, M1, M2 line strengths, oscillator strengths, and transition rates among these 272 levels are provided. Comparisons are made between the present two data sets, as well as with other available experimental and theoretical values. The present data are accurate enough for identification and deblending of emission lines involving the n = 3 levels, and are also useful for modeling and diagnosing fusion plasmas. (C) 2018 Elsevier Ltd. All rights reserved.
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| 2. |
- Xia, L., et al.
(författare)
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Resonance-enhanced electron-impact excitation of Cu-like gold
- 2017
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Pergamon Press. - 0022-4073 .- 1879-1352. ; 198, s. 48-58
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Tidskriftsartikel (refereegranskat)abstract
- Employing the independent-process and isolated-resonance approximations using distorted-waves (IPIRDW), we have performed a series of calculations of the resonance-enhanced electron-impact excitations (EIE) among 27 singly excited levels from the n <= 6 configurations of Cu-like gold (Au, Z = 79). Resonance excitation (RE) contributions from both the n = 4 -> 4 - 7 and n = 3 -> 4 core excitations have been considered. Our results demonstrate that RE contributions are significant and enhance the effective collision strengths (Upsilon) of certain excitations by up to an order of magnitude at low temperature (10(6.1) K), and are still important at relatively high temperature (10(7.5) K). Results from test calculations of the resonance-enhanced EIE processes among 16 levels from the n <= 5 configurations using both the Dirac R-matrix (DRM) and IPIRDW approaches agree very well with each other. This means that the close coupling effects are not important for this ion, and thus warrants the reliability of present resonance enhanced EIE data among the 27 levels. The results from the collisional-radiative model (CRM) show that, at 3000 eV, near where Cu-like Au is most abundant, RE contributions have important effects (up to 25%) on the density diagnostic line intensity ratios, which are sensitive near 10(20) cm(-3). The present work is the first EIE research including RE contributions for Cu-like Au. Our EIE data are more accurate than previous results due to our consideration of RE contributions, and the data should be helpful for modeling and diagnosing a variety of plasmas. (C) 2017 Elsevier Ltd. All rights reserved.
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| 3. |
- Blanton, Michael R., et al.
(författare)
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Sloan Digital Sky Survey IV : Mapping the Milky Way, Nearby Galaxies, and the Distant Universe
- 2017
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Ingår i: Astronomical Journal. - : IOP Publishing Ltd. - 0004-6256 .- 1538-3881. ; 154:1
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Tidskriftsartikel (refereegranskat)abstract
- We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and. high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z similar to 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z similar to 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs. and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the. Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July.
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| 4. |
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The Seventeenth Data Release of the Sloan Digital Sky Surveys : Complete Release of MaNGA, MaStar, and APOGEE-2 Data
- 2022
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Ingår i: Astrophysical Journal Supplement Series. - : Institute of Physics (IOP). - 0067-0049 .- 1538-4365. ; 259:2
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Tidskriftsartikel (refereegranskat)abstract
- This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys.
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