Herve Wozniak

Université de Montpellier | UM1 · Laboratoire Univers et Particules de Montpellier (LUPM)

Context. The stellar migration of the galactic disc stars has been invoked to explain the dispersion of stellar metallicity observed in the solar neighbourhood. Aims. We seek to identify the dynamical mechanisms underlying stellar migration in an isolated galaxy disc under the influence of a bar. Our approach is to analyse the diffusion of dynamica...

Context. Stellar migration of the galactic disc stars has been invoked to explain the dispersion of stellar metallicity observed in the solar neighborhood. Aims. We seek to identify the dynamical mechanisms underlying stellar migration in an isolated galaxy disc under the influence of a bar. Our approach is to analyze the diffusion of dynamical qua...

We are reexamining the problem of stellar migration in disk galaxies from a diffusion perspective. We use for the first time the formulation of the diffusion rates introduced by Chirikov, applied to both energy, E, and angular momentum, Lz , in self-consistent N-body experiments. We limit our study to the evolution of stellar disks well after the f...

We are re-examining the problem of stellar migration in disc galaxies from a diffusion perspective. We use for the first time the formulation of the diffusion rates introduced by \citet{1979PhR....52..263C}, applied to both energy $E$ and angular momentum $L_\mathrm{z}$ in self-consistent N$-$body experiments. We limit our study to the evolution of...

The Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE) is a blind narrow-band Halpha+[NII] imaging survey carried out with MegaCam at the Canada-France-Hawaii Telescope. The survey covers the whole Virgo cluster region from its core to one virial radius (104 deg^2). The sensitivity of the survey is of f(Halpha) ~ 4 x 10^-17 erg sec-1...

The Simulation Data Access Layer protocol (SimDAL) defines a set of resources and associated actions to discover and retrieve simulations and numerical models in the Virtual Observatory. SimDAL and the Simulation Data Model are dedicated to cover the needs for the publication and retrieval of any kind of simulations: N-body or MHD simulations, nume...

Double-barred galaxies account for almost one third of all barred galaxies, suggesting that secondary stellar bars, which are embedded in large-scale primary bars, are long-lived structures. However, up to now it has been hard to self-consistently simulate a disc galaxy that sustains two nested stellar bars for longer than a few rotation periods. N...

After finding an error in the procedure for computing the stellar masses of the Dwarf Galaxy Survey sample, we present here the correct values for the stellar masses.

In this document and the accompanying documents we describe a data model (Simulation Data Model) describing numerical computer simulations of astrophysical systems. The primary goal of this standard is to support discovery of simulations by describing those aspects of them that scientists might wish to query on, i.e. it is a model for meta-data des...

The distribution of gas in the central kiloparsec of a galaxy has a dynamically rapid evolution. Nonaxisymmetries in the gravitational potential of the galactic disk, such as a large scale stellar bar or spiral, can lead to significant radial motion of gaseous material from larger radii to the central region. The large influx of gas and the subsequ...

The Dwarf Galaxy Survey (DGS) program is studying low-metallicity galaxies using 230h of far-infrared (FIR) and submillimetre (submm) photometric and spectroscopic observations of the Herschel Space Observatory and draws to this a rich database of a wide range of wavelengths tracing the dust, gas and stars. This sample of 50 galaxies includes the l...

La problématique de la préservation et de la conservation du patrimoine a dépassé le cadre de la recherche en Histoire des Sciences pour devenir un enjeu de société. En utilisant l'exemple particulier de l'Observatoire astronomique de Strasbourg, on montre la nature des contraintes auxquelles est soumis l'observatoire, les antagonismes créés par de...

We have designed a model to compute dust abundances in chemodynamical N-body+SPH simulations. It includes the production by Asymptotic Giant Branch (AGB) stars, supernovae (SNe, type I and II), the destruction by shock induced by SNe and the growth of dust grains in the interstellar medium (ISM). The model takes advantage of the self-consistent che...

We present the 450-1550 GHz spectra of three nearby Seyfert galaxies (NGC1068, NGC7130 and NGC7582) taken with the Herschel SPIRE FTS. For the case of NGC1068 we reconstruct the nuclear spectral line energy distribution (SLED) of the CO lines, applying nonLTE radiative transfer and a Bayesian likelihood analysis to estimate the physical properties...

Galactic cirrus emission at far-infrared wavelengths affects many extragalactic observations. Separating this emission from that associated with extragalactic objects is both important and difficult. In this paper we discuss a particular case, the M81 group, and the identification of diffuse structures prominent in the infrared, but also detected a...

We present the observations of the starburst galaxy M82 taken with the Herschel SPIRE Fourier-transform spectrometer. The spectrum (194–671 μm) shows a prominent CO rotational ladder from J = 4–3 to 13–12 emitted by the central region of M82. The fundamental properties of the gas are well constrained by the high J lines observed for the first time....

We present Herschel SPIRE and PACS photometeric observations of the low metallicity (Z ~ 0.35 ) nearby dwarf galaxy, NGC 1705, in six wavelength bands as part of the Dwarf Galaxy Survey guaranteed time Herschel key program. We confirm the presence of two dominant circumnuclear IR-bright regions surrounding the central super star cluster that had be...

With appropriate spatial resolution, images of spiral galaxies in thermal infrared (~10 μm and beyond) often reveal a bright central component, distinct from the stellar bulge, superimposed on a disk with prominent spiral arms. ISO and Spitzer studies have shown that much of the scatter in the mid-infrared colors of spiral galaxies is related to ch...

By combining Herschel-SPIRE data with archival Spitzer, H i , and CO maps, we investigate the spatial distribution of gas and dust in the two famous grand-design spirals M 99 and M 100 in the Virgo cluster. Thanks to the unique resolution and sensitivity of the Herschel-SPIRE photometer, we are for the first time able to measure the distribution an...

We present infrared colours (in the 25-500 μm spectral range) and UV to radio continuum spectral energy distributions of a sample of 51 nearby galaxies observed with SPIRE on Herschel. The observed sample includes all morphological classes, from quiescent ellipticals to active starbursts. Active galaxies have warmer colour temperatures than norm...

We have recently identified a new radial migration mechanism resulting from the overlap of spiral and bar resonances in galactic disks. Here we confirm the efficiency of this mechanism in fully self-consistent, Tree-SPH simulations, as well as high-resolution pure N-body simulations. In all barred cases we clearly identify the effect of spiral-bar...

By combining Herschel-SPIRE data with archival Spitzer, HI, and CO maps, we investigate the spatial distribution of gas and dust in the two famous grand-design spirals M99 and M100 in the Virgo cluster. Thanks to the unique resolution and sensitivity of the Herschel-SPIRE photometer, we are for the first time able to measure the distribution and ex...

We present Herschel-SPIRE observations of the perturbed galaxy NGC4438 in the Virgo cluster. These images reveal the presence of extra-planar dust up to ~4-5 kpc away from the galaxy's disk. The dust closely follows the distribution of the stripped atomic and molecular hydrogen, supporting the idea that gas and dust are perturbed in a similar fashi...

We present Herschel SPIRE and PACS photometeric observations of the low metallicity (Z ~ 0.35 solar) nearby dwarf galaxy, NGC 1705, in six wavelength bands as part of the Dwarf Galaxy Survey guaranteed time Herschel Key Program. We confirm the presence of two dominant circumnuclear IR-bright regions surrounding the central super star cluster that h...

The standard method of mapping the interstellar medium in a galaxy, by observing the molecular gas in the CO 1-0 line and the atomic gas in the 21-cm line, is largely limited with current telescopes to galaxies in the nearby universe. In this letter, we use SPIRE observations of the galaxies M99 and M100 to explore the alternative approach of mappi...

We present the first Herschel PACS and SPIRE images of the low-metallicity galaxy NGC6822 observed from 70 to 500 mu and clearly resolve the HII regions with PACS and SPIRE. We find that the ratio 250/500 is dependent on the 24 mu surface brightness in NGC6822, which would locally link the heating processes of the coldest phases of dust in the ISM...

With appropriate spatial resolution, images of spiral galaxies in thermal infrared (~10 micron and beyond) often reveal a bright central component, distinct from the stellar bulge, superimposed on a disk with prominent spiral arms. ISO and Spitzer studies have shown that much of the scatter in the mid-infrared colors of spiral galaxies is related t...

We present the observations of the starburst galaxy M82 taken with the Herschel SPIRE Fourier Transform Spectrometer. The spectrum (194-671 {\mu}m) shows a prominent CO rotational ladder from J = 4-3 to 13-12 emitted by the central region of M82. The fundamental properties of the gas are well constrained by the high J lines observed for the first t...

We use Herschel Space Observatory data to place observational constraints on the peak and Rayleigh-Jeans slope of dust emission observed at 70-500 microns in the nearby spiral galaxy M81. We find that the ratios of wave bands between 160 and 500 microns are primarily dependent on radius but that the ratio of 70 to 160 micron emission shows no clear...

M 82 is a unique representative of a whole class of galaxies, starbursts with superwinds, in the Very Nearby Galaxy Survey with Herschel. In addition, its interaction with the M 81 group has stripped a significant portion of its interstellar medium from its disk. SPIRE maps now afford better characterization of the far-infrared emission from cool d...

We present Herschel-SPIRE observations at 250-500um of the giant elliptical galaxy M86 and examine the distribution of the resolved cold dust emission and its relation with other galactic tracers. The SPIRE images reveal three dust components: emission from the central region; a dust lane extending north-south; and a bright emission feature 10kpc t...

The Herschel Reference Survey is a guaranteed time Herschel key project and will be a benchmark study of dust in the nearby universe. The survey will complement a number of other Herschel key projects including large cosmological surveys that trace dust in the distant universe. We will use Herschel to produce images of a statistically-complete samp...

We compute UV to radio continuum spectral energy distributions of 51 nearby galaxies recently observed with SPIRE onboard Herschel and present infrared colours (in the 25-500 μm spectral range). SPIRE data of normal galaxies are well reproduced with a modified black body (β=2) of temperature T≃q 20 K. In ellipticals hosting a radio galaxy, the far-...

The Herschel Reference Survey is a Herschel guaranteed time key project and will be a benchmark study of dust in the nearby universe. The survey will complement a number of other Herschel key projects including large cosmological surveys that trace dust in the distant universe. We will use Herschel to produce images of a statistically-complete samp...

We aim to study of the formation and evolution of galaxies with high spatial and temporal resolution. We describe a new chemodynamical code to describe the physical interplay between the stars and the multiphase interstellar medium in galaxies, including a dust component. Preliminary results can be found in Champavert (2007).

By combining Herschel-SPIRE data with archival Spitzer, H i , and CO maps, we investigate the spatial distribution of gas and dust in the two famous grand-design spirals M 99 and M 100 in the Virgo cluster. Thanks to the unique resolution and sensitivity of the Herschel-SPIRE pho-tometer, we are for the first time able to measure the distribution a...

We investigate whether the formation mechanism of boxy and peanut-shaped (B/PS) bulges could depend on the gas content of the galaxy. We have performed N-body simulations with and without a gaseous component. In the second case star formation/feedback recipes have also been implemented to create new stellar populations. As in many previous studies,...

The Multi Unit Spectroscopic Explorer MUSE [MUSE public web site: http://muse.univ-lyon1.fr] is one of the second generation VLT instruments. MUSE is a wide-field optical integral field spectrograph operating in the visible wavelength range with improved spatial resolution. The MUSE Consortium consists of groups at Lyon (PI institute, CRAL), Gottin...

I briefly summarize the main results obtained by the HORIZON computational astrophysics project and described two on-line services (GalMer and GalICS/MoMaF) that intent to give access to the simulations. I discuss some issues that were raised when developing these services.

The relevance of the Tremaine-Weinberg (TW) method is tested for measuring bar, spiral, and inner structure pattern speeds using a gaseous velocity field. The TW method is applied to various simulated barred galaxies in order to demonstrate its validity in seven different configurations, including star formation and/or dark matter halo. The reliabi...

Context. Intermediate mass galaxies (> 10$^{10}$ $M_\odot$) at $z$ ~ 0.6 are the likeliest progenitors of the present-day, numerous population of spirals. There is growing evidence that they have evolved rapidly in the last 6 to 8 Gyr, and likely already have formed a significant fraction of their stellar mass, often showing perturbed morphologies...

The Large Program IMAGES is near 2/3 of its completion. It provides us with kinematics (GIRAFFE deployable IFUs), gas chemistry (FORS2), detailed morphologies (HST/ACS) and IR photometry (Spitzer) for a set of 70 galaxies representative of intermediate mass galaxies (MJ<=-20.3 or 1.5e10 Mo) at z=0.4-0.75. We discover that, 6 Gyr ago, a significant...

We present a first combined analysis of the morphological and dynamical properties for the intermediate-mass Galaxy Evolution Sequence (IMAGES) sample. It is a representative sample of 52 zËœ0.6 galaxies with M_stell from 1.5 to 15 × 1010~Mo that possesses 3D resolved kinematics and HST deep imaging in at least two broad band filters. We aim at...

Using the multi-integral field spectrograph GIRAFFE at VLT, we have derived the $K$-band Tully-Fisher relation (TFR) at $z \sim 0.6$ for a representative sample of 65 galaxies with emission lines ($W_\mathrm{0}\mathrm{(OII)}\ge15~\AA$). We confirm that the scatter in the $z \sim 0.6$ TFR is caused by galaxies with anomalous kinematics, and find a p...

The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation instrument in development for the Very Large Telescope (VLT) of the European Southern Observatory (ESO), due to begin operation in 2011/12. MUSE will be an extremely powerful integral-field spectrograph fed by a new multiple-laser adaptive optics system on the VLT. In its usual ope...

Using the multi-integral field spectrograph GIRAFFE at VLT, we have derived the K-band Tully-Fisher relation (TFR) at z Ëœ 0.6 for a representative sample of 65 galaxies with emission lines (W_0(OII)>=15 Å). We confirm that the scatter in the z Ëœ 0.6 TFR is caused by galaxies with anomalous kinematics, and find a positive and strong correlati...

The use of chemodynamical simulations of disc galaxies calibrated in B and K bands allows us to compare the location of Ultra Harmonic Resonance (UHR) and corotation (CR) with photometrically estimated bar lengths. We apply several observational criteria to determine bar lengths. We show that the minimum of ellipticity located just outside the bulk...

(abbreviated) We present the first results of the ESO large program, ``IMAGES'' which aims at obtaining robust measurements of the kinematics of distant galaxies using the multi-IFU mode of GIRAFFE on the VLT. 3D spectroscopy is essential to robustly measure the often distorted kinematics of distant galaxies (e.g., Flores et al. 2006). We derive th...

The HORIZON Project http://www.projet-horizon.fr/ federates numerical simulations activities with a program focused on Galaxy and Large Scale Structure Formation. The scientific objective is specifically oriented towards studying galaxy formation in a cosmological framework. This document presents the database architecture used to store the results...

We have developed a quick and accurate numerical tool to compute gas cooling irrespective of its chemical composition.

We report about the fact that the stellar population that is born in the gas inflowing towards the central regions can be vertically unstable leading to a B/PS feature remarkably bluer that the surrounding bulge. Using new chemodynamical simulations we show that this young population does not remain as flat as the gaseous nuclear disc and buckles o...

Figure 1. Schematic presentation of our new chemo-dynamical tool. See Champavert & Wozniak (2007a) for full details and references.

We have developed a quick and accurate numerical tool to compute gas cooling whichever its chemical composition.

We present some preliminary results obtained with a new galactic chemodynamical tool under development. In the framework of non-instantaneous recycling approach, we follow the interactions due to star formation and feedback processes. One of the main original features of our code is that we record the abundance evolution of several chemical element...

Redshift catalog of 691 objects in CDFS from low resolution VIMOS spectroscopy. (1 data file).

Recent analysis of stellar populations in barred galaxies have focused on the spatial distribution of stellar population ages and metallicities. However, barred galaxies are complex objects where dynamical instabilities play a leading role in shaping any spatial distribution. The age distribution of stellar populations should thus be analyzed from...

(Abbrev.) This paper prepares a series of papers analysing the Intermediate MAss Galaxy Evolution Sequence (IMAGES) up to z=1. Intermediate mass galaxies (MJ <=-20.3) are selected from the Chandra Deep Field South (CDFS) for which we identify a serious lack of spectroscopically determined redshifts..... We have spectroscopically identified 691 obje...

Chemodynamical disc galaxy simulations coupled with stellar populations synthesis models allow to build multi-wavelength images from numerical simulations, and then to follow their morphological evolution in colour and not only on the mass distribution. Using such technique, we present the evolution of several photometric observables, of the Tully-...

The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation VLT panoramic integral-field spectrograph under preliminary design study. MUSE has a field of 1x1 arcmin**2 sampled at 0.2x0.2 arcsec**2 and is assisted by the VLT ground layer adaptive optics ESO facility using four laser guide stars. The simultaneous spectral range is 465-930 nm,...

We have made hydro/N-body simulations with and without star formation to shed some light on the conditions under which a central kinematically cold stellar component (characterized by a velocity dispersion drop or \sigma-drop) could be created in a hot medium (e.g. a bulge) and survive enough time to be observed. We found that the timescale for a \...

We present Sauron 2D spectrography of the central 1.5 kpc of the nearby Sey2 galaxy NGC1068, encompassing the well-known NIR inner bar. We have successively disentangled the respective contributions of the ionized gas and stars, thus deriving their 2D distribution and kinematics. The [OIII] and Hbeta emission lines exhibit very different spatial di...

Context.This paper prepares a series of papers analysing the Intermediate MAss Galaxy Evolution Sequence (IMAGES) up to a redshift of one. Intermediate mass galaxies ($M_{\rm J} \leq -20.3$) are selected from the Chandra Deep Field South (CDFS) for which we identify a serious lack of spectroscopically determined redshifts.Aims.Our primary aim in th...

We have investigated the accuracy and reliability of six methods used to determine the length of stellar bars in galaxies or N-body simulations. All these methods use ellipse fitting and Fourier decomposition of the surface brightness. We have applied them to N-body simulations that include stars, gas, star formation, and feedback. Stellar particle...

The initial concept of Virtual Observatory has been so far con-fined to observational data products and services. However, a great interest has been recently shown in including products of theoretical research, lead-ing to the concept of Theoretical Virtual Observatory (TVO). I thus report on TVO development progress in France and in international...

We have used a set of N-body simulations including stars, gas and star formation, photometrically calibrated in B and K wavebands to compare the bar length with the location of some dynamic resonances. Bar length has been determined by various observational criteria which use ellipse fitting and Fourier analysis tools. We show that it is possible t...

We present a detailed analysis of the evolution of a simulated isolated disc galaxy. The simulation includes stars, gas, star formation and simple chemical yields. Stellar particles are split in two populations: the old one is present at the beginning of the simulation and is calibrated according to various ages and metallicities; the new populatio...

We present an interpretation of the stellar velocity dispersion drops discovered in the nuclear regions of three barred galaxy hosts of active/starburst galactic nuclei (NGC 1097, NGC 1808 and NGC 5728) by Emsellem et al. ([CITE]). Using self-consistent $N$-body simulations including stars, gas and star formation, we show that young stars born in t...

We have calibrated self-consistent simulations of isolated disc galaxies including star, gas and star formation with the spectro-photometric evolutionary model GISSEL2000 (Bruzual and Charlot, 1993). With this approach we can compare morphologies studying mass and luminous distributions. We present an example about the evolution of bar ellipticity,...

We have studied the evolution of isolated galaxies over several Gyr using a self-consistent N-body code including stars, gas and star formation. The results of our simulations are calibrated using spectrophotometric evolution models. We thus simultaneously analyse kinematical and photometrical evolution of the various stellar populations born durin...

I review recent optical and infrared observations of the circumnuclear regions of active galaxies. I will draw attention to the importance of the AGN/starburst interplay in composite galaxies.