# Atomic Data Revisions for Transitions Relevant to Observations of Interstellar, Circumgalactic, and Intergalactic Matter

## TL;DR

This paper compiles and assesses atomic data for key absorption lines relevant to interstellar, circumgalactic, and intergalactic medium studies, aiding accurate element abundance measurements in astrophysics.

## Contribution

It provides a comprehensive, updated compilation of atomic data, including wavelengths and oscillator strengths, with assessments of recent determinations for lines observed in various cosmic media.

## Key findings

- Approximately 22% of lines have updated oscillator strengths differing by ≥0.1 dex.
- The compilation includes wavelengths, oscillator strengths, and accuracy grades for lines beyond 911.753 Å.
- The resource supports absorption line studies of the ISM, CGM, and IGM, enhancing future astrophysical research.

## Abstract

Measurements of element abundances in galaxies from astrophysical spectroscopy depend sensitively on the atomic data used. With the goal of making the latest atomic data accessible to the community, we present a compilation of selected atomic data for resonant absorption lines at wavelengths longward of 911.753 {\AA} (the \ion{H}{1} Lyman limit), for key heavy elements (heavier than atomic number 5) of astrophysical interest. In particular, we focus on the transitions of those ions that have been observed in the Milky Way interstellar medium (ISM), the circumgalactic medium (CGM) of the Milky Way and/or other galaxies, and the intergalactic medium (IGM). We provide wavelengths, oscillator strengths, associated accuracy grades, and references to the oscillator strength determinations. We also attempt to compare and assess the recent oscillator strength determinations. For about 22\% of the lines that have updated oscillator strength values, the differences between the former values and the updated ones are $\gtrsim$~0.1 dex. Our compilation will be a useful resource for absorption line studies of the ISM, as well as studies of the CGM and IGM traced by sight lines to quasars and gamma-ray bursts. Studies (including those enabled by future generations of extremely large telescopes) of absorption by galaxies against the light of background galaxies will also benefit from our compilation.