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Lego Figure holding a lego telescope. Photo

Henrik Hartman

Researcher (Leave of Absence)

Lego Figure holding a lego telescope. Photo

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

Author

  • Asli Pehlivan
  • Hampus Nilsson
  • Henrik Hartman

Summary, in English

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.

Department/s

  • Lund Observatory - Undergoing reorganization

Publishing year

2015

Language

English

Publication/Series

Astronomy & Astrophysics

Volume

582

Document type

Journal article

Publisher

EDP Sciences

Topic

  • Astronomy, Astrophysics and Cosmology

Keywords

  • atomic data
  • methods: laboratory: atomic
  • techniques: spectroscopic

Status

Published

Project

  • Experimental and Computational Atomic Spectroscopy for Astrophysics
  • Experimental and Observational Atomic Astrophysics

ISBN/ISSN/Other

  • ISSN: 0004-6361