Comparing emission- and absorption-based gas-phase metallicities in GRB host galaxies at iz /i=2-4 using JWST

0585244 - ASÚ 2025 US eng J - Journal Article
Schady, P. - Yates, R. M. - Christensen, L. - Thöne, Christina … Total 37 authors
Comparing emission- and absorption-based gas-phase metallicities in GRB host galaxies at iz /i=2-4 using JWST.
Monthly Notices of the Royal Astronomical Society. Roč. 529, č. 3 (2024), s. 2807-2831. ISSN 0035-8711. E-ISSN 1365-2966
Institutional support: RVO:67985815
Keywords : gamma-ray-burst * galaxies abundances * high-redshift
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 4.8, year: 2022
Method of publishing: Open access

We present results from a JWST/NIRSpec programme to investigate for the first time the relation between the metallicity of neutral gas probed in absorption by GRB afterglows and the metallicity of the star-forming regions for the same host galaxy sample. Using an initial sample of eight GRB host galaxies at z = 2.1-4.7, we find a tight relation between absorption and emission line metallicities when using the recently proposed R(over dot) metallicity diagnostic (+/- 0.2 dex). This agreement implies a relatively chemically homogeneous multiphase interstellar medium and indicates that absorption and emission line probes can be directly compared. However, the relation is less clear when using other diagnostics, such as R-23 and R-3. We also find possible evidence of an elevated N/O ratio in the host galaxy of GRB 090323 at z = 4.7, consistent with what has been seen in other z > 4 galaxies. Ultimate confirmation of an enhanced N/O ratio and of the relation between absorption and emission line metallicities will require a more direct determination of the emission line metallicity via the detection of temperature-sensitive auroral lines in our GRB host galaxy sample.
Permanent Link: https://hdl.handle.net/11104/0353669