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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

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


S Gillman

AL Tiley

CM Harrison

J Molina

RG Bower

M Cirasuolo

Edo Ibar

D Obreschkow


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.

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
Public URL


Published Journal Article (7 Mb)

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2021 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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