Final published version
Licence: CC BY: Creative Commons Attribution 4.0 International License
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - LEGA-C: Analysis of Dynamical Masses from Ionized Gas and Stellar Kinematics at z ∼ 0.8
AU - Straatman, Caroline M. S.
AU - van der Wel, Arjen
AU - van Houdt, Josha
AU - Bezanson, Rachel
AU - Bell, Eric F.
AU - van Dokkum, Pieter
AU - D’Eugenio, Francesco
AU - Franx, Marijn
AU - Gallazzi, Anna
AU - de Graaff, Anna
AU - Maseda, Michael
AU - Meidt, Sharon E.
AU - Muzzin, Adam
AU - Sobral, David
AU - Wu, Po-Feng
PY - 2022/4/1
Y1 - 2022/4/1
N2 - We compare dynamical mass estimates based on spatially extended stellar and ionized gas kinematics (M dyn,* and M dyn,eml, respectively) of 157 star-forming galaxies at 0.6 ≤ z <1. Compared with z ∼ 0, these galaxies have enhanced star formation rates, with stellar feedback likely affecting the dynamics of the gas. We use LEGA-C DR3, the highest-redshift data set that provides sufficiently deep measurements of a K s -band limited sample. For M dyn,*, we use Jeans anisotropic multi-Gaussian expansion models. For M dyn,eml, we first fit a custom model of a rotating exponential disk with uniform dispersion, whose light is projected through a slit and corrected for beam smearing. We then apply an asymmetric drift correction based on assumptions common in the literature to the fitted kinematic components to obtain the circular velocity, assuming hydrostatic equilibrium. Within the half-light radius, M dyn,eml is on average lower than M dyn,*, with a mean offset of –0.15 ± 0.016 dex and galaxy-to-galaxy scatter of 0.19 dex, reflecting the combined random uncertainty. While data of higher spatial resolution are needed to understand this small offset, it supports the assumption that the galaxy-wide ionized gas kinematics do not predominantly originate from disruptive events such as star formation–driven outflows. However, a similar agreement can be obtained without modeling from the integrated emission line dispersions for axis ratios q <0.8. This suggests that our current understanding of gas kinematics is not sufficient to efficiently apply asymmetric drift corrections to improve dynamical mass estimates compared with observations lacking the signal-to-noise ratio required for spatially extended dynamics.
AB - We compare dynamical mass estimates based on spatially extended stellar and ionized gas kinematics (M dyn,* and M dyn,eml, respectively) of 157 star-forming galaxies at 0.6 ≤ z <1. Compared with z ∼ 0, these galaxies have enhanced star formation rates, with stellar feedback likely affecting the dynamics of the gas. We use LEGA-C DR3, the highest-redshift data set that provides sufficiently deep measurements of a K s -band limited sample. For M dyn,*, we use Jeans anisotropic multi-Gaussian expansion models. For M dyn,eml, we first fit a custom model of a rotating exponential disk with uniform dispersion, whose light is projected through a slit and corrected for beam smearing. We then apply an asymmetric drift correction based on assumptions common in the literature to the fitted kinematic components to obtain the circular velocity, assuming hydrostatic equilibrium. Within the half-light radius, M dyn,eml is on average lower than M dyn,*, with a mean offset of –0.15 ± 0.016 dex and galaxy-to-galaxy scatter of 0.19 dex, reflecting the combined random uncertainty. While data of higher spatial resolution are needed to understand this small offset, it supports the assumption that the galaxy-wide ionized gas kinematics do not predominantly originate from disruptive events such as star formation–driven outflows. However, a similar agreement can be obtained without modeling from the integrated emission line dispersions for axis ratios q <0.8. This suggests that our current understanding of gas kinematics is not sufficient to efficiently apply asymmetric drift corrections to improve dynamical mass estimates compared with observations lacking the signal-to-noise ratio required for spatially extended dynamics.
KW - 310
KW - Galaxies and Cosmology
U2 - 10.3847/1538-4357/ac4e18
DO - 10.3847/1538-4357/ac4e18
M3 - Journal article
VL - 928
JO - The Astrophysical Journal
JF - The Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 126
ER -