The resolved chemical abundance properties within the interstellar medium of star-forming galaxies at z≈ 1.5

Gillman, S; Puglisi, A; Dudzevičiūtė, U; Swinbank, AM; Tiley, AL; Harrison, CM; Molina, J; Sharples, RM; Bower, RG; Cirasuolo, M; Ibar, Edo; Obreschkow, D

Abstract

We exploit the unprecedented depth of integral field data from the KMOS Ultra-deep Rotational Velocity Survey (KURVS) to analyse the strong (Hα) and forbidden ([NII], [SII]) emission line ratios in 22 main-sequence galaxies at z ≈ 1.5. Using the [NII]/Hα emission-line ratio, we confirm the presence of the stellar mass – gas-phase metallicity relation at this epoch, with galaxies exhibiting on average 0.13 ± 0.04 dex lower gas-phase metallicity (12 + log(O/H)M13 = 8.40 ± 0.03) for a given stellar mass (log10(M∗[M] = 10.1 ± 0.1) .than local main-sequence galaxies. We determine the galaxy-integrated [SII] doublet ratio, with a median value of [SII]λ6716/λ6731 = 1.26 ± 0.14 equivalent to an electron density of log10(ne[cm−3]) = 1.95 ± 0.12. Utilising CANDELS HST multi-band imaging we define the pixel surface-mass and star-formation rate density in each galaxy and spatially resolve the fundamental metallicity relation at z ≈ 1.5, finding an evolution of 0.05 ± 0.01 dex compared to the local relation. We quantify the intrinsic gas-phase metallicity gradient within the galaxies using the [NII]/Hα calibration, finding a median annuli-based gradient of Z/R = −0.015 ± 0.005 dex kpc−1. Finally, we examine the azimuthal variations in gas-phase metallicity, which show a negative correlation with the galaxy integrated star-formation rate surface density (rs = −0.40, ps = 0.07) but no connection to the galaxies kinematic or morphological properties nor radial variations in stellar mass surface density or star formation rate surface density. This suggests both the radial and azimuthal variations in interstellar medium properties are connected to the galaxy integrated density of recent star formation.

Citation

Gillman, S., Puglisi, A., Dudzevičiūtė, U., Swinbank, A., Tiley, A., Harrison, C., …Obreschkow, D. (2022). The resolved chemical abundance properties within the interstellar medium of star-forming galaxies at z≈ 1.5. Monthly Notices of the Royal Astronomical Society, 512(3), 3480-3499. https://doi.org/10.1093/mnras/stac580

• Journal Article Type: Article
• Acceptance Date: Feb 25, 2022
• Online Publication Date: Mar 7, 2022
• Publication Date: 2022-05
• Deposit Date: Jun 24, 2022
• Publicly Available Date: Jun 24, 2022
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 512
• Issue: 3
• Pages: 3480-3499
• DOI: https://doi.org/10.1093/mnras/stac580
• Public URL: https://durham-repository.worktribe.com/output/1203179