We present the 0.6 < z < 2.6 evolution of the ionized gas velocity dispersion in 175 star-forming disk galaxies based on data from the full integral field spectroscopic survey. In a forward-modeling Bayesian framework including instrumental effects and beam-smearing, we fit simultaneously the observed galaxy velocity and velocity dispersion along the kinematic major axis to derive the intrinsic velocity dispersion σ 0. We find a reduction of the average intrinsic velocity dispersion of disk galaxies as a function of cosmic time, from σ 0 ∼ 45 km s-1 at z ∼ 2.3 to σ 0 ∼ 30 km s-1 at z ∼ 0.9. There is substantial intrinsic scatter (σσ0,int ≈ 10km s-1) around the best-fit σ 0-z relation beyond what can be accounted for from the typical measurement uncertainties (δσ 0 ≈ 12 km s-1), independent of other identifiable galaxy parameters. This potentially suggests a dynamic mechanism such as minor mergers or variation in accretion being responsible for the scatter. Putting our data into the broader literature context, we find that ionized and atomic+molecular velocity dispersions evolve similarly with redshift, with the ionized gas dispersion being ∼10-15 km s-1 higher on average. We investigate the physical driver of the on average elevated velocity dispersions at higher redshift and find that our galaxies are at most marginally Toomre-stable, suggesting that their turbulent velocities are powered by gravitational instabilities, while stellar feedback as a driver alone is insufficient. This picture is supported through comparison with a state-of-the-art analytical model of galaxy evolution.

Ubler, H., Genzel, R., Wisnioski, E., Schreiber, N., Shimizu, T., Price, S., et al. (2019). The Evolution and Origin of Ionized Gas Velocity Dispersion from z ∼ 2.6 to z ∼ 0.6 with KMOS3D. THE ASTROPHYSICAL JOURNAL, 880(1) [10.3847/1538-4357/ab27cc].

The Evolution and Origin of Ionized Gas Velocity Dispersion from z ∼ 2.6 to z ∼ 0.6 with KMOS3D

Fossati M.;
2019

Abstract

We present the 0.6 < z < 2.6 evolution of the ionized gas velocity dispersion in 175 star-forming disk galaxies based on data from the full integral field spectroscopic survey. In a forward-modeling Bayesian framework including instrumental effects and beam-smearing, we fit simultaneously the observed galaxy velocity and velocity dispersion along the kinematic major axis to derive the intrinsic velocity dispersion σ 0. We find a reduction of the average intrinsic velocity dispersion of disk galaxies as a function of cosmic time, from σ 0 ∼ 45 km s-1 at z ∼ 2.3 to σ 0 ∼ 30 km s-1 at z ∼ 0.9. There is substantial intrinsic scatter (σσ0,int ≈ 10km s-1) around the best-fit σ 0-z relation beyond what can be accounted for from the typical measurement uncertainties (δσ 0 ≈ 12 km s-1), independent of other identifiable galaxy parameters. This potentially suggests a dynamic mechanism such as minor mergers or variation in accretion being responsible for the scatter. Putting our data into the broader literature context, we find that ionized and atomic+molecular velocity dispersions evolve similarly with redshift, with the ionized gas dispersion being ∼10-15 km s-1 higher on average. We investigate the physical driver of the on average elevated velocity dispersions at higher redshift and find that our galaxies are at most marginally Toomre-stable, suggesting that their turbulent velocities are powered by gravitational instabilities, while stellar feedback as a driver alone is insufficient. This picture is supported through comparison with a state-of-the-art analytical model of galaxy evolution.
Articolo in rivista - Articolo scientifico
galaxies: evolution; galaxies: high-redshift; galaxies: ISM; galaxies: kinematics and dynamics
English
2019
880
1
48
none
Ubler, H., Genzel, R., Wisnioski, E., Schreiber, N., Shimizu, T., Price, S., et al. (2019). The Evolution and Origin of Ionized Gas Velocity Dispersion from z ∼ 2.6 to z ∼ 0.6 with KMOS3D. THE ASTROPHYSICAL JOURNAL, 880(1) [10.3847/1538-4357/ab27cc].
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/324967
Citazioni
  • Scopus 83
  • ???jsp.display-item.citation.isi??? 69
Social impact