Laboratory Astrophysics: new accurate atomic data for astrophysics

Laboratory Astrophysics: new accurate atomic data for astrophysics Vision: Cutting-edge astronomical observations are now producing spectra with unparalleled resolution across the infrared (IR), visible, and ultraviolet (UV), enabled by advanced telescopes such as JWST, VLT, HST, Keck II, Subaru, and UKIRT. These high-quality, expensively acquired, spectra are highlighting the critical necessity for laboratory atomic data of at least matching accuracy to ensure their meaningful interpretation. The inadequacy of large amounts of existing laboratory atomic data frequently emerges as the weakest link in observational analyses, with much atomic data stemming from experiments conducted over six decades ago using low-resolution instruments. In many cases, order-of-magnitude improvements in the accuracy of atomic data are required for the unambiguous identification of all features of interest in astronomical spectra. Astronomy heavily relies on the accuracy and abundance of atomic data, making it as crucial to progress in the field as observational instruments themselves. With the imminent operation of next-generation telescopes such as the ELT, the demands for precise and comprehensive atomic data are only set to increase. Atomic data play a pivotal role in deciphering the intricate line structures blended within astronomical spectra and form the foundation for reliable astronomical spectrum synthesis and chemical element abundance determinations. Theoretical calculations alone cannot yield atomic data with the requisite precision for these applications and laboratory measurements remain the sole source of sufficiently accurate data. Objectives: In this research programme the Imperial College London (ICL) Spectroscopy group continues to take up the challenge of meeting this acute need by measuring and analysing atomic spectra of many astrophysically important elements. We specialise in high-resolution studies of transition wavelengths, energy levels, transition probabilities (log(gf)s, oscillator strengths, f-values), and line broadening effects, including hyperfine and isotope structure. Using high-resolution Fourier transform spectroscopy (FTS), from the infra-red to vacuum ultraviolet, we will continue to significantly advance the quality and quantity of atomic data, achieving substantial reductions in uncertainties for transition wavelengths and energy levels, often exceeding an order-of-magnitude in improvement, and measuring transition probabilities accurate to just a few percent. The high resolution of FTS also enables us to determine line broadening effects such as hyperfine and isotope structure, crucial data for accurate stellar abundance measurements. The accuracy of the atomic data produced by the ICL group meets and exceeds the requirements of modern astrophysical analyses. Our new atomic data is incorporated into databases and model atmosphere codes, benefitting astronomers worldwide.