Halfway to the Peak: Kinematic Signatures of Stable Rotating Disks in Luminous Infrared Galaxies at z = 0.5–0.6
Abstract
We present a kinematic study of six IR-luminous galaxies observed with the Mid-infrared Instrument Medium-resolution Spectrometer (MIRI/MRS) on board JWST. These galaxies lie at z = 0.5–0.6, midway between the present day and the peak of cosmic star formation (SF). Our sample spans a range of SF and active galactic nucleus (AGN) contributions to the mid-IR emission. We characterize the dynamical state of these IR-luminous galaxies and assess how AGN activity influences the kinematics of the interstellar medium. Using mid-IR tomic lines, we map galaxy kinematics beyond the local Universe for the first time. The spatial resolution of MIRI/MRS (3.0 kpc for 0 . ″ 46 at z ∼ 0.55) allows us to resolve the internal kinematics of our targets. We compute kinematic maps in three different emission lines ([Ar II ]6.99 μ m, [Ne II ]12.81 μ m, and H 2 0-0 S(5)6.91 μ m). Using the [Ar II ]6.99 μ m kinematic maps, we derive rotation curves for these sources. All galaxies exhibit ordered rotation, with V / σ ≥ 2, consistent with stable disks. Although some show minor disturbances, we find no strong evidence for recent major mergers or galaxy-wide ionized outflows. We find no correlation between V / σ and AGN fraction, suggesting AGN activity does not significantly disrupt global kinematics or that disk disruption is not required to trigger AGN. However, galaxies with higher AGN fractions show elevated central dispersions, indicating localized turbulence, possibly due to AGN feedback, stellar feedback, accretion, or bulge structure. These IR-luminous galaxies likely represent mature, rotationally supported disks, with AGN activation occurring after disk assembly.
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BibTeX
@article{eleazer2026halfway,
title = {{Halfway to the Peak: Kinematic Signatures of Stable Rotating Disks in Luminous Infrared Galaxies at z = 0.5–0.6}},
author = {Miriam Eleazer and Alexandra Pope and Anna Sajina and Lin Yan and Jason Young and Stacey Alberts and Lee Armus and Kristen Coppin and Daniel Dale and Duncan Farrah and Thiago Gonçalves and Jed Mckinney and Nicole Nesvadba and Patrick Ogle and Roxana Popescu and Sylvain Veilleux},
journal = {The Astrophysical Journal},
year = {2026},
month = jun,
doi = {10.3847/1538-4357/ae64fb},
url = {https://hal.science/hal-05842704v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Halfway to the Peak: Kinematic Signatures of Stable Rotating Disks in Luminous Infrared Galaxies at z = 0.5–0.6
AU - Miriam Eleazer
AU - Alexandra Pope
AU - Anna Sajina
AU - Lin Yan
AU - Jason Young
AU - Stacey Alberts
AU - Lee Armus
AU - Kristen Coppin
AU - Daniel Dale
AU - Duncan Farrah
AU - Thiago Gonçalves
AU - Jed Mckinney
AU - Nicole Nesvadba
AU - Patrick Ogle
AU - Roxana Popescu
AU - Sylvain Veilleux
PY - 2026
DA - 2026/06/04
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/ae64fb
UR - https://hal.science/hal-05842704v1
AB - We present a kinematic study of six IR-luminous galaxies observed with the Mid-infrared Instrument Medium-resolution Spectrometer (MIRI/MRS) on board JWST. These galaxies lie at z = 0.5–0.6, midway between the present day and the peak of cosmic star formation (SF). Our sample spans a range of SF and active galactic nucleus (AGN) contributions to the mid-IR emission. We characterize the dynamical state of these IR-luminous galaxies and assess how AGN activity influences the kinematics of the interstellar medium. Using mid-IR tomic lines, we map galaxy kinematics beyond the local Universe for the first time. The spatial resolution of MIRI/MRS (3.0 kpc for 0 . ″ 46 at z ∼ 0.55) allows us to resolve the internal kinematics of our targets. We compute kinematic maps in three different emission lines ([Ar II ]6.99 μ m, [Ne II ]12.81 μ m, and H 2 0-0 S(5)6.91 μ m). Using the [Ar II ]6.99 μ m kinematic maps, we derive rotation curves for these sources. All galaxies exhibit ordered rotation, with V / σ ≥ 2, consistent with stable disks. Although some show minor disturbances, we find no strong evidence for recent major mergers or galaxy-wide ionized outflows. We find no correlation between V / σ and AGN fraction, suggesting AGN activity does not significantly disrupt global kinematics or that disk disruption is not required to trigger AGN. However, galaxies with higher AGN fractions show elevated central dispersions, indicating localized turbulence, possibly due to AGN feedback, stellar feedback, accretion, or bulge structure. These IR-luminous galaxies likely represent mature, rotationally supported disks, with AGN activation occurring after disk assembly.
SN - 0004-637X
SN - 1538-4357
ER -