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The KMOS Lens-Amplified Spectroscopic Survey (KLASS): kinematics and clumpiness of low-mass galaxies at cosmic noon

2020/06/25 by Marianne Girard, M. Girard, Charlotte Mason +18
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gravitational lens #Gravitational microlensing #Kinematics #Physics #Redshift #Star formation #Stellar, planetary, and galactic studies #Telescope #Velocity dispersion #astro-ph.GA

paper · pdf · doi:10.1093/mnras/staa1907

19 pages, 9 figures. Accepted for publication in MNRAS

arxiv created 2020/06/25 · openalex publication_date 2020/07/03 · arxiv updated 2020/07/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

ABSTRACT We present results from the KMOS Lens-Amplified Spectroscopic Survey (KLASS), an ESO Very Large Telescope (VLT) large program using gravitational lensing to study the spatially resolved kinematics of 44 star-forming galaxies at 0.6 < z < 2.3 with a stellar mass of 8.1 < log(M⋆/M⊙) < 11.0. These galaxies are located behind six galaxy clusters selected from the Hubble Space Telescope Grism Lens-Amplified Survey from Space (GLASS). We find that the majority of the galaxies show a rotating disc, but most of the rotation-dominated galaxies only have a low υ rot/σ0 ratio (median of υrot/σ0 ∼ 2.5). We explore the Tully–Fisher relation by adopting the circular velocity, V circ=(υ rot2+3.4σ 02)1/2, to account for pressure support. We find that our sample follows a Tully–Fisher relation with a positive zero-point offset of +0.18 dex compared to the local relation, consistent with more gas-rich galaxies that still have to convert most of their gas into stars. We find a strong correlation between the velocity dispersion and stellar mass in the KLASS sample. When combining our data to other surveys from the literature, we see an increase of the velocity dispersion with stellar mass at all redshift. We obtain an increase of υrot/σ0 with stellar mass at 0.5 < z < 1.0. This could indicate that massive galaxies settle into regular rotating discs before the low-mass galaxies. For higher redshift (z > 1), we find a weak increase or flat trend. We find no clear trend between the rest-frame UV clumpiness and the velocity dispersion and υrot/σ0. This could suggest that the kinematic properties of galaxies evolve after the clumps formed in the galaxy disc or that the clumps can form in different physical conditions.

Citations