Title: The Belgian repository of fundamental atomic data and stellar spectra (BRASS). I. Cross-matching atomic databases of astrophysical interest,
Abstract: Fundamental atomic parameters, such as oscillator strengths, play a key role
in modelling and understanding the chemical composition of stars in the
universe. Despite the significant work underway to produce these parameters for
many astrophysically important ions, uncertainties in these parameters remain
large and can propagate throughout the entire field of astronomy. The Belgian
repository of fundamental atomic data and stellar spectra (BRASS) aims to
provide the largest systematic and homogeneous quality assessment of atomic
data to date in terms of wavelength, atomic and stellar parameter coverage. To
prepare for it, we first compiled multiple literature occurrences of many
individual atomic transitions, from several atomic databases of astrophysical
interest, and assessed their agreement. Several atomic repositories were
searched and their data retrieved and formatted in a consistent manner. Data
entries from all repositories were cross-matched against our initial BRASS
atomic line list to find multiple occurrences of the same transition. Where
possible we used a non-parametric cross-match depending only on electronic
configurations and total angular momentum values. We also checked for duplicate
entries of the same physical transition, within each retrieved repository,
using the non-parametric cross-match. We report the cross-matched transitions
for each repository and compare their fundamental atomic parameters. We find
differences in log(gf) values of up to 2 dex or more. We also find and report
that ~2% of our line list and Vienna Atomic Line Database retrievals are
composed of duplicate transitions. Finally we provide a number of examples of
atomic spectral lines with different log(gf) values, and discuss the impact of
these uncertain log(gf) values on quantitative spectroscopy. All cross-matched
atomic data and duplicate transitions are available to download at
brass.sdf.org.