We studied the evolution of the gas kinematics of galaxies by performing hydrodynamical simulations in a cosmological scenario. We paid special attention to the origin of the scatter of the Tully-Fisher relation and the features which could be associated with mergers and interactions. We extended the study by De Rossi et al. (2010) and analysed their whole simulated sample which includes both, gas disc-dominated and spheroid-dominated systems. We found that mergers and interactions can affect the rotation curves directly or indirectly inducing a scatter in the Tully-Fisher Relation larger than the simulated evolution since z=3. In agreement with previous works, kinematical indicators which combine the rotation velocity and dispersion velocity in their definitions lead to a tighter relation. In addition, when we estimated the rotation velocity at the maximum of the rotation curve, we obtained the best proxy for the potential well regardless of morphology.
(Abridged) We trace the interaction processes of galaxies at intermediate redshift by measuring the irregularity of their ionized gas kinematics, and investigate these irregularities as a function of the environment (cluster versus field) and of morphological type (spiral versus irregular). Our sample consists of 92 distant galaxies. 16 cluster (z~0.3 and z~0.5) and 29 field galaxies (mean z=0.44) of these have velocity fields with sufficient signal to be analyzed. We find that the fraction of galaxies that have irregular gas kinematics is remarkably similar in galaxy clusters and in the field…
Kinematical studies of low and high redshift galaxies enables to probe galaxy formation and evolution scenarios. Integral field spectroscopy is a powerful tool to study with accuracy nearby galaxies kinematics. Recent observations also gives a new 2D vision of high redshift galaxies kinematics. This work mostly relies on the kinematical sample of galaxies GHASP. This control sample, composed of 203 local spiral and irregular galaxies in low density environments observed with Fabry-Perot techniques in the Ha line (6563 A), is by now the largest sample of Fabry-Perot data. After a revue on Fabry…
Recent calculations using non-linear relativistic cosmological perturbation theory show biases in the mean luminosity distance and distance modulus at low redshift. We show that these effects may be understood very simply as a non-relativistic, and purely kinematic, Malmquist-like bias, and we describe how the effect changes if one averages over sources that are limited by apparent magnitude. This effect is essentially identical to the distance bias from small-scale random velocities that has previously been considered by astronomers, though we find that the standard formula overestimates the …
The backreaction of inhomogeneities describes the effect of inhomogeneous structure on average properties of the Universe. We investigate this approach by testing the consistency of cosmological $N$-body simulations as non-linear structure evolves. Using the Delaunay Tessellation Field Estimator (DTFE), we calculate the kinematical backreaction $Q$ from simulations on different scales in order to measure how much $N$-body simulations should be corrected for this effect. This is the first step towards creating fully relativistic and inhomogeneous $N$-body simulations. In this paper we compare t…
We present two-dimensional H_alpha velocity fields for 20 late-type, disk-dominated spiral galaxies, the largest sample to date with high-resolution H_alpha velocity fields for bulgeless disks. From these data we derive rotation curves and the location of the kinematic centers. The galaxy sample was selected to contain nucleated and non-nucleated galaxies, which allows us to investigate what impact the gas kinematics in the host disk have on the presence (or absence) of a nuclear star cluster. In general, we find that the velocity fields span a broad range of morphologies. While some galaxies …
Evolution of galaxies is one of the most actual topics in astrophysics. Among the most important factors determining the evolution are two galactic components which are difficult or even impossible to detect optically: the gaseous disks and the dark matter halo. We use deep Hubble Space Telescope images to construct a two-component (bulge + disk) model for stellar matter distribution of galaxies. Properties of the galactic components are derived using a three-dimensional galaxy modeling software, which also estimates disk thickness and inclination angle. We add a gas disk and a dark matter hal…
The frequently observed lopsidedness of the distribution of stars and gas in disc galaxies is still considered as a major problem in galaxy dynamics. It is even discussed as an imprint of the formation history of discs and the evolution of baryons in dark matter haloes. Here, we analyse a selected sample of 70 galaxies from the Westerbork HI Survey of Spiral and Irregular Galaxies. The HI data allow us to follow the morphology and the kinematics out to very large radii. In the present paper, we present the rotation curves and study the kinematic asymmetry. We extract the rotation curves of rec…
We review our current understanding of the internal dynamical properties of the dwarf spheroidal galaxies surrounding the Milky Way. These are the most dark matter dominated galaxies, and as such may be considered ideal laboratories to test the current concordance cosmological model, and in particular provide constraints on the nature of the dominant form of dark matter. We discuss the latest observations of the kinematics of stars in these systems, and how these may be used to derive their mass distribution. We tour through the various dynamical techniques used, with emphasis on the complemen…
We prove from the modified gravity (MG) galaxy/halo mock catalogs that the shape of the pairwise kinematic Sunyaev-Zeldovich (kSZ) power spectrum $P_{\rm kSZ}$ has constraining power on discriminating different gravity theories on cosmological scales. By varying the effective optical depth $τ_{\rm T}$ as a free parameter, we verify that the $τ_{\rm T}$-$f$ (the linear growth rate) degeneracy in the linear theory of $P_{\rm kSZ}$ is broken down by the non-linear structure growth and the scale-dependence of $f$ in some MG theories. Equivalently speaking, the shape of $P_{\rm kSZ}$ alone could be…
The aim of this project is to determine the consistency of an assumed cosmological model by means of a detailed analysis of the brightness profiles of distant galaxies.Starting from the theory developed by Ellis and Perry (1979) connecting the angular diameter distance obtained from a relativistic cosmological model and the detailed photometry of galaxies, we assume the presently most accepted cosmological model with non-zero cosmological constant and attempt to predict the brightness profiles of galaxies of a given redshift. Then this theoretical profile can be compared to observational data …
We analyze the spectra, spatial distributions and kinematics of Ha, [NII] and [SII] emission in a sample of 42, z~2.2 UV/optically selected star forming galaxies (SFGs) from the SINS & zC-SINF surveys, 35 of which were observed in the adaptive optics mode of SINFONI. This is supplemented by kinematic data from 48 z~1-2.5 galaxies from the literature. We find that the kinematic classification of the high-z SFGs as `dispersion dominated' or `rotation dominated' correlates most strongly with their intrinsic sizes. Smaller galaxies are more likely `dispersion-dominated' for two main reasons: 1) Th…
We study the kinematics of galaxies within massive clusters, as a probe of the physics of star-formation quenching within clusters. Using N-body simulations, we argue that satellite kinematics provide information about galaxy infall that is complementary to the (instantaneous) spatial distribution of satellites. Comparing the simulation results with measurements of real cluster galaxies, we find evidence that the kinematics of red (quiescent) satellite galaxies are consistent with earlier infall times than that of blue (star-forming) satellites.
We present new medium resolution kinematic data for a sample of 21 dwarf early-type galaxies (dEs) mainly in the Virgo cluster, obtained with the WHT and INT telescopes at the Roque de los Muchachos Observatory (La Palma, Spain). These data are used to study the origin of the dwarf elliptical galaxy population inhabiting clusters. We confirm that dEs are not dark matter dominated galaxies, at least up to the half-light radius. We also find that the observed galaxies in the outer parts of the cluster are mostly rotationally supported systems with disky morphological shapes. Rotationally support…
We show the kinematic equivalence between cosmological models driven by Dirac-Born-Infeld fields $ϕ$ with constant proper velocity of the brane and exponential potential $V=V_0e^{-Bϕ}$ and interactive cosmological systems with Modified Holographic Ricci type fluids as dark energy in flat Friedmann-Robertson-Walker cosmologies.
The kinematics of the Milky Way (MW) and M31, the dominant galaxies in the Local Group (LG), can be used to estimate the LG total mass. New results on the M31 proper motion have recently been used to improve that estimate. Those results are based on kinematic priors that are sometimes guided and evaluated using cosmological N-body simulations. However, the kinematic properties of simulated LG analogues could be biased due to the effective power spectrum truncation induced by the small size of the parent simulation. Here we explore the dependence of LG kinematics on the simulation box size to a…
With the aim of understanding which physical processes are primarily responsible for the transformation of spiral galaxies into S0s in clusters, we study the gas kinematics, morphological disturbances, and the Tully-Fisher relation (TFR) of distant galaxies in various environments. We use the ESO Distant Cluster Survey (EDisCS) dataset, that spans a broad range of cluster and galaxy properties at 0.3 < z < 0.8. Our results indicate that the physical mechanism acting on cluster galaxies (with M_B < -20 mag) must be strong enough to significantly disturb the gas in cluster galaxies, but at the s…
The kinematics of galaxies provide valuable insights in their physics and assembly history. Kinematics are governed not only by the gravitational potential, but also by merger events and stellar feedback processes such as stellar winds and supernova explosions. Aims. We aim at identifying what governs the kinematics in a sample of SDSS selected nearby starburst galaxies, by obtaining spatially resolved measurements of the gas and stellar kinematics. We obtain near-infrared integral field K-band spectroscopy with VLT/SINFONI of 15 compact starburst galaxies. We derive the integrated as well as …
Recent years have witnessed a substantial increase in our ability to trace the spatially resolved properties of rapidly star-forming galaxies in the high-redshift universe and numerous studies have suggested the importance of turbulent gas-phase kinematics. In this submission to the Astro 2010 Decadal survey we outline some of the major outstanding questions regarding the kinematics and formation history of these galaxies, such as the prevalence of various kinematic models, the relation to lower surface-brightness populations and faint AGN, and the implications for the evolution of gas accreti…
The Gaussian Kinematic Formula (GKF, see Adler and Taylor (2007,2011)) is an extremely powerful tool allowing for explicit analytic predictions of expected values of Minkowski functionals under realistic experimental conditions for cosmological data collections. In this paper, we implement Minkowski functionals on multipoles and needlet components of CMB fields, thus allowing a better control of cosmic variance and extraction of information on both harmonic and real domains; we then exploit the GKF to provide their expected values on spherical maps, in the presence of arbitrary sky masks, and …
We present a spectral decomposition technique and its applications to a sample of galaxies hosting large-scale counter-rotating stellar disks. Our spectral decomposition technique allows to separate and measure the kinematics and the properties of the stellar populations of both the two counter-rotating disks in the observed galaxies at the same time. Our results provide new insights on the epoch and mechanism of formation of these galaxies.
Recent observations have shown that star-forming galaxies like our own Milky Way evolve kinematically into ordered thin disks over the last ~8 billion years since z=1.2, undergoing a process of "disk settling." For the first time, we study the kinematic evolution of a suite of four state of the art "zoom in" hydrodynamic simulations of galaxy formation and evolution in a fully cosmological context and compare with these observations. Until now, robust measurements of the internal kinematics of simulated galaxies were lacking as the simulations suffered from low resolution, overproduction of st…
A sample of completely isolated S0 galaxies has been studied by means of long-slit spectroscopy at the Russian 6-m telescope. 7 of 12 galaxies have revealed a presence of extended ionized-gas discs which rotation is mostly decoupled from the stellar kinematics: 5 of 7 (71+/-17%) galaxies show a visible counterrotation of the ionized-gas component with respect to the stellar component. The emission-line diagnostics demonstrates a wide range of the gas excitation mechanisms, although a pure excitation by young stars is rare. We conclude that in all cases the extended gaseous discs in our sample …
We use spatially resolved two-dimensional stellar velocity maps over a $107"\times 107"$ field of view to investigate the kinematic features of 90 early-type galaxies above stellar mass $10^{11.5}M_\odot$ in the MASSIVE survey. We measure the misalignment angle $Ψ$ between the kinematic and photometric axes and identify local features such as velocity twists and kinematically distinct components. We find 46% of the sample to be well aligned ($Ψ< 15^{\circ}$), 33% misaligned, and 21% without detectable rotation (non-rotators). Only 24% of the sample are fast rotators, the majority of which (91%…
We present the results of a kinematic study of planetary nebulae in the extreme outskirts of two spiral galaxies, M83 (NGC 5236) and M94 (NGC 4736). We find that in the inner regions of the galaxies, the vertical velocity dispersion (sigma_z) falls off exponentially with the light, as expected for a constant mass-to-light ratio, constant thickness disk. However, starting at four optical scale lengths, sigma_z asymptotes out at roughly 20 km/s. Our analysis finds evidence for significant flaring in the outer regions as well, especially in M94. These observations are in excellent agreement with …
The main objective of my thesis was to provide us, for the first time, with a reliable view of the distant Hubble sequence, and its evolution over the past 6 Gyr. To achieve this goal, we have created a new morphological classification method which (1) includes all the available observational data, (2) can be easily reproduced, and (3) presents a negligible subjectivity. This method allows us to study homogeneously the morphology of local and distant galaxies. The first step has been to study the evolution of galaxies using the IMAGES survey. This survey allowed us to establish the kinematic s…
We have directly compared MgII halo gas kinematics to the rotation velocities derived from emission/absorption lines of the associated host galaxies. Our 0.096<z<0.148 volume-limited sample comprises 13 ~L* galaxies, with impact parameters of 12-90 kpc from background quasars sight-lines, associated with 11 MgII absorption systems with MgII equivalent widths 0.3< W_r(2796)<2.3A. For only 5/13 galaxies, the absorption resides to one side of the galaxy systemic velocity and trends to align with one side of the galaxy rotation curve. The remainder have absorption that spans both sides of the gala…
The stellar kinematics of the spheroids and discs of S0 galaxies contain clues to their formation histories. Unfortunately, it is difficult to disentangle the two components and to recover their stellar kinematics in the faint outer parts of the galaxies using conventional absorption line spectroscopy. This paper therefore presents the stellar kinematics of six S0 galaxies derived from observations of planetary nebulae (PNe), obtained using the Planetary Nebula Spectrograph. To separate the kinematics of the two components, we use a maximum-likelihood method that combines the discrete kinemati…
We combined two-dimensional kinematic and morphology information on the Halpha emission, obtained using near-infrared integral field spectroscopy, with broad-band photometry to investigate the dynamical structure and the physical properties of a sample of ten late-type galaxies at 1.0 < z < 1.5. The sample displays a range of kinematical types which include one merger, one face-on galaxy, and eight objects showing evidence of rotation. Among these eight objects, half are rotation-dominated galaxies, while the rest are dispersion-dominated. We found also that two galaxies out of the rotation-do…
The combination of strong gravitational lensing and stellar kinematics provides a powerful and robust method to investigate the mass and dynamical structure of early-type galaxies. We demonstrate this approach by analysing two massive ellipticals from the XLENS Survey for which both high-resolution HST imaging and X-Shooter spectroscopic observations are available. We adopt a flexible axisymmetric two-component mass model for the lens galaxies, consisting of a generalised NFW dark halo and a realistic self-gravitating stellar mass distribution. For both systems, we put constraints on the dark …
The last seven years have seen an explosion in the number of Integral Field galaxy surveys, obtaining resolved 2D spectroscopy, especially at high-redshift. These have taken advantage of the mature capabilities of 8-10 m class telescopes and the development of associated technology such as AO. Surveys have leveraged both high spectroscopic resolution enabling internal velocity measurements and high spatial resolution from AO techniques and sites with excellent natural seeing. For the first time, we have been able to glimpse the kinematic state of matter in young, assembling star-forming galaxi…
We consider a generic Metric-Affine Cosmological setup and classify some particularly interesting specific cases of Perfect Hyperfluids. In particular, we present the form of conservation laws for the cases of pure spin, pure dilation and pure shear fluids. We also develop the concept of an incompressible hyperfluid and pay special attention to the case of a hypermomentum preserving hyperfluid. We also give a specific example on the emergence of the spin, dilation and shear currents through matter-connection couplings. In addition, starting from the generalized acceleration equation for the sc…
Low luminosity dwarf galaxies provide stringent constraints on the nature of dark matter. Establishing these constraints depends on precise kinematic measurements of individual stars. In this overview for non-specialists, we describe current and future prospects for three unique tests of dark matter using resolved stellar kinematics in low luminosity galaxies: the overall number of satellite galaxies around the Milky Way, dark-matter annihilation radiation from dwarf galaxies, and their internal density profiles. We then assess the prospects for meaningfully testing theories of dark matter bas…
