TY - JOUR

T1 - Dynamical properties of z similar to 4.5 dusty star-forming galaxies and their connection with local early-type galaxies

AU - Rizzo, Francesca

AU - Vegetti, Simona

AU - Fraternali, Filippo

AU - Stacey, Hannah R.

AU - Powell, Devon

PY - 2021/9/11

Y1 - 2021/9/11

N2 - There is a large consensus that gas in high-z galaxies is highly turbulent, because of a combination of stellar feedback processes and gravitational instabilities driven by mergers and gas accretion. In this paper, we present the analysis of a sample of five Dusty Star Forming Galaxies (DSFGs) at 4 less than or similar to z less than or similar to 5. Taking advantage of the magnifying power of strong gravitational lensing, we quantified their kinematic and dynamical properties from ALMA observations of their [C II] emission line. We combined the dynamical measurements obtained for these galaxies with those obtained from previous studies to build the largest sample of z similar to 4.5 galaxies with high-quality data and sub-kpc spatial resolutions, so far. We found that all galaxies in the sample are dynamically cold, with rotation-to-random motion ratios, V/sigma, between 7 and 15. The relation between their velocity dispersions and their star formation rates indicates that stellar feedback is sufficient to sustain the turbulence within these galaxies and no further mechanisms are needed. In addition, we performed a rotation curve decomposition to infer the relative contribution of the baryonic (gas, stars) and dark matter components to the total gravitational potentials. This analysis allowed us to compare the structural properties of the studied DSFGs with those of their descendants, the local early type galaxies. In particular, we found that five out of six galaxies of the sample show the dynamical signature of a bulge, indicating that the spheroidal component is already in place at z similar to 4.5.

AB - There is a large consensus that gas in high-z galaxies is highly turbulent, because of a combination of stellar feedback processes and gravitational instabilities driven by mergers and gas accretion. In this paper, we present the analysis of a sample of five Dusty Star Forming Galaxies (DSFGs) at 4 less than or similar to z less than or similar to 5. Taking advantage of the magnifying power of strong gravitational lensing, we quantified their kinematic and dynamical properties from ALMA observations of their [C II] emission line. We combined the dynamical measurements obtained for these galaxies with those obtained from previous studies to build the largest sample of z similar to 4.5 galaxies with high-quality data and sub-kpc spatial resolutions, so far. We found that all galaxies in the sample are dynamically cold, with rotation-to-random motion ratios, V/sigma, between 7 and 15. The relation between their velocity dispersions and their star formation rates indicates that stellar feedback is sufficient to sustain the turbulence within these galaxies and no further mechanisms are needed. In addition, we performed a rotation curve decomposition to infer the relative contribution of the baryonic (gas, stars) and dark matter components to the total gravitational potentials. This analysis allowed us to compare the structural properties of the studied DSFGs with those of their descendants, the local early type galaxies. In particular, we found that five out of six galaxies of the sample show the dynamical signature of a bulge, indicating that the spheroidal component is already in place at z similar to 4.5.

KW - gravitational lensing: strong

KW - galaxies: evolution

KW - galaxies: high-redshift

KW - galaxies: ISM

KW - galaxies: kinematics and dynamics

KW - submillimetre: galaxies

KW - SPECTROSCOPIC SURVEY KROSS

KW - COLD GAS ACCRETION

KW - SIMILAR-TO 1-2

KW - DARK-MATTER

KW - ATLAS(3D) PROJECT

KW - MOLECULAR GAS

KW - SUBMILLIMETER GALAXIES

KW - VELOCITY DISPERSION

KW - ELLIPTIC GALAXIES

KW - STELLAR FEEDBACK

U2 - 10.1093/mnras/stab2295

DO - 10.1093/mnras/stab2295

M3 - Journal article

VL - 507

SP - 3952

EP - 3984

JO - Royal Astronomical Society. Monthly Notices

JF - Royal Astronomical Society. Monthly Notices

SN - 0035-8711

IS - 3

ER -