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Laboratory oscillator strengths of Sc I in the near-infrared region for astrophysical applications

Pehlivan, Asli LU ; Nilsson, Hampus LU and Hartman, Henrik LU (2015) In Astronomy & Astrophysics 582.
Abstract
Context. Atomic data is crucial for astrophysical investigations. To understand the formation and evolution of stars, we need to analyse their observed spectra. Analysing a spectrum of a star requires information about the properties of atomic lines, such as wavelengths and oscillator strengths. However, atomic data of some elements are scarce, particularly in the infrared region, and this paper is part of an effort to improve the situation on near-IR atomic data. Aims. This paper investigates the spectrum of neutral scandium, Sc I, from laboratory measurements and improves the atomic data of Sc I lines in the infrared region covering lines in R, I, J, and K bands. Especially, we focus on measuring oscillator strengths for Sc I lines... (More)
Context. Atomic data is crucial for astrophysical investigations. To understand the formation and evolution of stars, we need to analyse their observed spectra. Analysing a spectrum of a star requires information about the properties of atomic lines, such as wavelengths and oscillator strengths. However, atomic data of some elements are scarce, particularly in the infrared region, and this paper is part of an effort to improve the situation on near-IR atomic data. Aims. This paper investigates the spectrum of neutral scandium, Sc I, from laboratory measurements and improves the atomic data of Sc I lines in the infrared region covering lines in R, I, J, and K bands. Especially, we focus on measuring oscillator strengths for Sc I lines connecting the levels with 4p and 4s configurations. Methods. We combined experimental branching fractions with radiative lifetimes from the literature to derive oscillator strengths (f-values). Intensity-calibrated spectra with high spectral resolution were recorded with Fourier transform spectrometer from a hollow cathode discharge lamp. The spectra were used to derive accurate oscillator strengths and wavelengths for Sc I lines, with emphasis on the infrared region. Results. This project provides the first set of experimental Sc I lines in the near-infrared region for accurate spectral analysis of astronomical objects. We derived 63 log(gf) values for the lines between 5300 angstrom and 24 300 angstrom. The uncertainties in the f-values vary from 5% to 20%. The small uncertainties in our values allow for an increased accuracy in astrophysical abundance determinations. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
atomic data, methods: laboratory: atomic, techniques: spectroscopic
in
Astronomy & Astrophysics
volume
582
publisher
EDP Sciences
external identifiers
  • wos:000363538500098
  • scopus:84945121848
ISSN
0004-6361
DOI
10.1051/0004-6361/201526813
language
English
LU publication?
yes
id
734b0b07-f005-4a3f-a419-42a530c7e308 (old id 8383418)
date added to LUP
2015-12-18 14:27:58
date last changed
2017-09-17 06:28:33
@article{734b0b07-f005-4a3f-a419-42a530c7e308,
  abstract     = {Context. Atomic data is crucial for astrophysical investigations. To understand the formation and evolution of stars, we need to analyse their observed spectra. Analysing a spectrum of a star requires information about the properties of atomic lines, such as wavelengths and oscillator strengths. However, atomic data of some elements are scarce, particularly in the infrared region, and this paper is part of an effort to improve the situation on near-IR atomic data. Aims. This paper investigates the spectrum of neutral scandium, Sc I, from laboratory measurements and improves the atomic data of Sc I lines in the infrared region covering lines in R, I, J, and K bands. Especially, we focus on measuring oscillator strengths for Sc I lines connecting the levels with 4p and 4s configurations. Methods. We combined experimental branching fractions with radiative lifetimes from the literature to derive oscillator strengths (f-values). Intensity-calibrated spectra with high spectral resolution were recorded with Fourier transform spectrometer from a hollow cathode discharge lamp. The spectra were used to derive accurate oscillator strengths and wavelengths for Sc I lines, with emphasis on the infrared region. Results. This project provides the first set of experimental Sc I lines in the near-infrared region for accurate spectral analysis of astronomical objects. We derived 63 log(gf) values for the lines between 5300 angstrom and 24 300 angstrom. The uncertainties in the f-values vary from 5% to 20%. The small uncertainties in our values allow for an increased accuracy in astrophysical abundance determinations.},
  articleno    = {A98},
  author       = {Pehlivan, Asli and Nilsson, Hampus and Hartman, Henrik},
  issn         = {0004-6361},
  keyword      = {atomic data,methods: laboratory: atomic,techniques: spectroscopic},
  language     = {eng},
  publisher    = {EDP Sciences},
  series       = {Astronomy & Astrophysics},
  title        = {Laboratory oscillator strengths of Sc I in the near-infrared region for astrophysical applications},
  url          = {http://dx.doi.org/10.1051/0004-6361/201526813},
  volume       = {582},
  year         = {2015},
}