There is a large consensus that gas in high-$z$ galaxies is highly turbulent,because of a combination of stellar feedback processes and gravitationalinstabilities driven by mergers and gas accretion. In this paper, we presentthe analysis of a sample of five Dusty Star Forming Galaxies (DSFGs) at $4\lesssim z\lesssim 5$. Taking advantage of the magnifying power of stronggravitational lensing, we quantified their kinematic and dynamical propertiesfrom ALMA observations of their [CII] emission line. We combined the dynamicalmeasurements obtained for these galaxies with those obtained from previousstudies to build the largest sample of $z \sim 4.5$ galaxies with high-qualitydata and sub-kpc spatial resolutions, so far. We found that all galaxies in thesample are dynamically cold, with rotation-to-random motion ratios, $V/\sigma$,between 7 to 15. The relation between their velocity dispersions and theirstar-formation rates indicates that stellar feedback is sufficient to sustainthe turbulence within these galaxies and no further mechanisms are needed. Inaddition, we performed a rotation curve decomposition to infer the relativecontribution of the baryonic (gas, stars) and dark matter components to thetotal gravitational potentials. This analysis allowed us to compare thestructural properties of the studied DSFGs with those of their descendants, thelocal early type galaxies. In particular, we found that five out of sixgalaxies of the sample show the dynamical signature of a bulge, indicating thatthe spheroidal component is already in place at $z \sim 4.5$.

Abridged for arXiv: In this work, we apply a powerful new technique in orderto observationally derive accurate assembly histories through a self-consistentcombined stellar dynamical and population galaxy model. We present thisapproach for three edge-on lenticular galaxies from the Fornax3D project -- FCC153, FCC 170, and FCC 177 -- in order to infer their mass assembly historiesindividually and in the context of the Fornax cluster. The method was tested onmock data from simulations to quantify its reliability. We find that thegalaxies studied here have all been able to form dynamically-cold (intrinsicvertical velocity dispersion $\sigma_z \lesssim 50\ {\rm km}\ {\rm s}^{-1}$)stellar disks after cluster infall. Moreover, the pre-existing (old) highangular momentum components have retained their angular momentum (orbitalcircularity $\lambda_z > 0.8$) through to the present day. Comparing thederived assembly histories with a comparable galaxy in a low-densityenvironment -- NGC 3115 -- we find evidence for cluster-driven suppression ofstellar accretion and merging. We measured the intrinsic stellarage--velocity-dispersion relation and find that the shape of the relation isconsistent with galaxies in the literature across redshift. There is tentativeevidence for enhancement in the luminosity-weighted intrinsic vertical velocitydispersion due to the cluster environment. But importantly, there is anindication that metallicity may be a key driver of this relation. We finallyspeculate that the cluster environment is responsible for the S0 morphology ofthese galaxies via the gradual external perturbations, or `harassment',generated within the cluster.

Cosmological models predict that galaxies forming in the early Universeexperience a chaotic phase of gas accretion and star formation, followed by gasejection due to feedback processes. Galaxy bulges may assemble later viamergers or internal evolution. Here we present submillimeter observations (withspatial resolution of 700 parsecs) of ALESS 073.1, a starburst galaxy atredshift z~5, when the Universe was 1.2 billion years old. This galaxy's coldgas forms a regularly rotating disk with negligible noncircular motions. Thegalaxy rotation curve requires the presence of a central bulge in addition to astar-forming disk. We conclude that massive bulges and regularly rotating diskscan form more rapidly in the early Universe than predicted by models of galaxyformation.