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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 ≲ z ≲ 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 ∼ 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/σ, between 7 to 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 ∼ 4.5.

We present a 3D Bayesian method to model the kinematics of strongly lensed galaxies from spatially-resolved emission-line observations. This technique enables us to simultaneously recover the lens-mass distribution and the source kinematics directly from the 3D data cube. We have tested this new method with simulated OSIRIS observations for nine star-forming lensed galaxies with different kinematic properties. The simulated rotation curves span a range of shapes which are prototypes of different morphological galaxy types, from dwarf to massive spiral galaxies. We have found that the median relative accuracy on the inferred lens and kinematic parameters are at the level of 1 and 2 per cent, respectively. We have also tested the robustness of the technique against different inclination angles, signal-to-noise ratios, the presence of warps or non-circular motions and we have found that the accuracy stays within a few per cent in most cases. This technique represents a significant step forward with respect to the methods used until now, as the lens parameters and the kinematics of the source are derived from the same 3D data. This enables us to study the possible degeneracies between the two and estimate the uncertainties on all model parameters consistently.

The distribution of galaxies in the stellar specific angular momentum versus stellar mass plane ( j -M ) provides key insights into their formation mechanisms. In this paper, we determine the location in this plane of a sample of ten field/group unbarred lenticular (S0) galaxies from the CALIFA survey. We performed a bulge-disc decomposition both photometrically and kinematically to study the stellar specific angular momentum of the disc components alone and understand the evolutionary links between S0s and other Hubble types. We found that eight of our S0 discs have a distribution in the j -M plane that is fully compatible with that of spiral discs, while only two have values of j lower than the spirals. These two outliers show signs of recent merging. Our results suggest that merger and interaction processes are not the dominant mechanisms in S0 formation in low-density environments. Instead, S0s appear to be the result of secular processes and the fading of spiral galaxies after the shutdown of star formation.where J is the angular momentum, E is the total energy (kinetic plus potential) and M is the total mass (Peebles 1969). Cosmological N-body simulations (e.g. Bullock et al. 2001;Macciò et al. 2007) showed that the spin parameter

We present a novel Bayesian methodology to jointly model photometry and deep Hubble Space Telescope (HST ) 2d grism spectroscopy of high-redshift galaxies. Our requiem2d code measures both unresolved and resolved stellar populations, ages, and star-formation histories (SFHs) for the ongoing REQIUEM (REsolving QUIEscent Magnified) Galaxies Survey, which targets strong gravitationally lensed quiescent galaxies at z∼2. We test the accuracy of requiem2d using a simulated sample of massive galaxies at z∼2 from the Illustris cosmological simulation and find we recover the general trends in SFH and median stellar ages. We further present a pilot study for the REQUIEM Galaxies Survey: MRG-S0851, a quintuply-imaged, massive (log M * /M = 11.02±0.04) red galaxy at z = 1.883±0.001. With an estimated gravitational magnification of µ = 5.7 +0.4 −0.2 , we sample the stellar populations on 0.6 kpc physical size bins. The global mass-weighted median age is constrained to be 1.8 +0.3 −0.2 Gyr, and our spatially resolved analysis reveals that MRG-S0851 has a flat age gradient in the inner 3 kpc core after taking into account the subtle effects of dust and metallicity on age measurements, favoring an early formation scenario. The analysis for the full REQUIEM-2D sample will be presented in a forthcoming paper with a beta-release of the requiem2d code.

We resolve the host galaxies of seven gravitationally lensed quasars at redshift 1.5 to 2.8 using observations with the Atacama Large (sub-)Millimetre Array. Using a visibility-plane lens modelling technique, we create pixellated reconstructions of the dust morphology, and CO line morphology and kinematics. We find that the quasar hosts in our sample can be distinguished into two types: 1) galaxies characterised by clumpy, extended dust distributions (Reff ∼ 2 kpc) and mean star formation rate surface densities comparable to sub-mm-selected dusty star-forming galaxies (ΣSFR ∼ 3 M⊙ yr−1 kpc−2 ); 2) galaxies that have sizes in dust emission similar to coeval passive galaxies and compact starbursts (Reff ∼ 0.5 kpc), with high mean star formation rate surface densities (ΣSFR = 400–4500 M⊙ yr−1 kpc−2 ) that may be Eddington-limited or super-Eddington. The small sizes of some quasar hosts suggests that we observe them at a stage in their transformation into compact spheroids via dissipative contraction, where a high density of dynamically unstable gas leads to efficient star formation and black hole accretion. For the one system where we probe the bulk of the gas reservoir, we find a gas fraction of just 0.06 ± 0.04 and a depletion timescale of 50 ± 40 Myr, suggesting it is transitioning into quiescence. In general, we expect that the extreme level of star formation in the compact quasar host galaxies will rapidly exhaust their gas reservoirs and could quench with or without help from active galactic nuclei feedback.

While the kinematics of galaxies up to z ∼ 3 have been characterized in detail, only a handful of galaxies at high redshift (z > 4) have been examined in such a way. The Atacama Large Millimeter/submillimeter Array (ALMA) Large Program to INvestigate [CII] at Early times (ALPINE) survey observed a statistically significant sample of 118 star-forming main sequence galaxies at z = 4.4 − 5.9 in [CII]158μm emission, increasing the number of such observations by nearly 10x. A preliminary qualitative classification of these sources revealed a diversity of kinematic types (i.e., rotators, mergers, and dispersion-dominated systems). In this work, we supplement the initial classification by applying quantitative analyses to the ALPINE data: a tilted ring model (TRM) fitting code (3DBarolo), a morphological classification (Gini-M20), and a set of disk identification criteria. Of the 75 [CII]-detected ALPINE galaxies, 29 are detected at sufficient significance and spatial resolution to allow for TRM fitting and the derivation of morphological and kinematic parameters. These 29 sources constitute a high-mass subset of the ALPINE sample (M* > 109.5 M⊙). We robustly classify 14 of these sources (six rotators, five mergers, and three dispersion-dominated systems); the remaining sources showing complex behaviour. By exploring the G-M20 of z > 4 rest-frame FIR and [CII] data for the first time, we find that our 1″ ∼ 6 kpc resolution data alone are insufficient to separate galaxy types. We compare the rotation curves and dynamical mass profiles of the six ALPINE rotators to the two previously detected z ∼ 4 − 6 unlensed main sequence rotators, finding high rotational velocities (∼50 − 250 km s−1) and a diversity of rotation curve shapes.

We present a study of the stellar host galaxy, CO (1–0) molecular gas distribution and AGN emission on 50–500 pc-scales of the gravitationally lensed dust-obscured AGN MG J0751+2716 and JVAS B1938+666 at redshifts 3.200 and 2.059, respectively. By correcting for the lensing distortion using a grid-based lens modelling technique, we spatially locate the different emitting regions in the source plane for the first time. Both AGN host galaxies have 300–500 pc-scale size and surface brightness consistent with a bulge/pseudo-bulge, and 2 kpc-scale AGN radio jets that are embedded in extended molecular gas reservoirs that are 5–20 kpc in size. The CO (1–0) velocity fields show structures possibly associated with discs (elongated velocity gradients) and interacting objects (off-axis velocity components). There is evidence for a decrement in the CO (1–0) surface brightness at the location of the host galaxy, which may indicate radiative feedback from the AGN, or offset star formation. We find CO–H2 conversion factors of around αCO = 1.5 ± 0.5 (K km s−1 pc2)−1, molecular gas masses of >3 × 1010 M⊙, dynamical masses of ∼1011 M⊙, and gas fractions of around 60 per cent. The intrinsic CO line luminosities are comparable to those of unobscured AGN and dusty star-forming galaxies at similar redshifts, but the infrared luminosities are lower, suggesting that the targets are less efficient at forming stars. Therefore, they may belong to the AGN feedback phase predicted by galaxy formation models, because they are not efficiently forming stars considering their large amount of molecular gas.