The Belgian repository of fundamental atomic data and stellar spectra (BRASS) II. Quality assessment of atomic data for unblended lines in FGK stars. (arXiv:1902.03821v1 [astro-ph.SR])

The Belgian repository of fundamental atomic data and stellar spectra (BRASS) II. Quality assessment of atomic data for unblended lines in FGK stars. (arXiv:1902.03821v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Laverick_M/0/1/0/all/0/1">M. Laverick</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lobel_A/0/1/0/all/0/1">A. Lobel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Royer_P/0/1/0/all/0/1">P. Royer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Merle_T/0/1/0/all/0/1">T. Merle</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Martayan_C/0/1/0/all/0/1">C. Martayan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hoof_P/0/1/0/all/0/1">P.A.M. van Hoof</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Swaelmen_M/0/1/0/all/0/1">M. Van der Swaelmen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+David_M/0/1/0/all/0/1">M. David</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hensberge_H/0/1/0/all/0/1">H. Hensberge</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Thienpont_E/0/1/0/all/0/1">E. Thienpont</a>

Fundamental atomic transition parameters, such as oscillator strengths and
wavelengths, play a key role in modelling and understanding the chemical
composition of stars in the universe. Despite the significant work under way to
produce these parameters for many ions, uncertainties in these parameters
remain large and can limit the accuracy of chemical abundance determinations.
The Belgian repository of fundamental atomic data and stellar spectra (BRASS)
aims to provide a large systematic and homogeneous quality assessment of the
atomic data available for quantitative spectroscopy. BRASS shall compare
synthetic spectra against extremely high quality observed spectra, at a
resolution of ~85000 and signal-noise ratios of ~1000, for around 20 bright
BAFGK spectral type stars, in order to evaluate the atomic data available for
over a thousand potentially useful spectral lines. A large-scale homogeneous
selection of atomic lines is performed by synthesising theoretical spectra of
literature atomic lines, for FGK-type stars including the Sun, resulting in a
selection of 1091 theoretically deep and unblended lines, in the wavelength
range 4200-6800~AA, which may be suitable for quality assessment.
Astrophysical log(gf) values are determined for the 1091 transitions using two
commonly employed methods. The agreement of these log(gf) values are used to
select well-behaving lines for quality assessment. 845 atomic lines were found
to be suitable for quality assessment, of which 408 were found to be robust
against systematic differences between analysis methods. Around 54% of the
quality-assessed lines were found to have at least one literature log(gf) value
in agreement with our derived values, though the remaining values can disagree
by as much as 0.5 dex. Only 38% of FeI lines were found to have sufficiently
accurate log(gf) values, increasing to ~70-75% for the remaining Fe-group
lines.

Fundamental atomic transition parameters, such as oscillator strengths and
wavelengths, play a key role in modelling and understanding the chemical
composition of stars in the universe. Despite the significant work under way to
produce these parameters for many ions, uncertainties in these parameters
remain large and can limit the accuracy of chemical abundance determinations.
The Belgian repository of fundamental atomic data and stellar spectra (BRASS)
aims to provide a large systematic and homogeneous quality assessment of the
atomic data available for quantitative spectroscopy. BRASS shall compare
synthetic spectra against extremely high quality observed spectra, at a
resolution of ~85000 and signal-noise ratios of ~1000, for around 20 bright
BAFGK spectral type stars, in order to evaluate the atomic data available for
over a thousand potentially useful spectral lines. A large-scale homogeneous
selection of atomic lines is performed by synthesising theoretical spectra of
literature atomic lines, for FGK-type stars including the Sun, resulting in a
selection of 1091 theoretically deep and unblended lines, in the wavelength
range 4200-6800~AA, which may be suitable for quality assessment.
Astrophysical log(gf) values are determined for the 1091 transitions using two
commonly employed methods. The agreement of these log(gf) values are used to
select well-behaving lines for quality assessment. 845 atomic lines were found
to be suitable for quality assessment, of which 408 were found to be robust
against systematic differences between analysis methods. Around 54% of the
quality-assessed lines were found to have at least one literature log(gf) value
in agreement with our derived values, though the remaining values can disagree
by as much as 0.5 dex. Only 38% of FeI lines were found to have sufficiently
accurate log(gf) values, increasing to ~70-75% for the remaining Fe-group
lines.

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