MIGALE : A MULTIPARAMETRIC VIRTUAL INSTRUMENT TO STUDY GALAXY EVOLUTION

09/2003 Rencontres de Blois proceedingsGalaxy evolution is a complex process where both the inner evolution of stellar population, gas and dust,and the external effects, like interactions and exchanges with the environment, have to be taken into account.It has been fundamental in the last years to be able to build and use homogeneouscatalogues both in the local and the far universe. The observation of galaxy morphology and kinematicsas a function of the redshift is indeed necessary to disentangle the various galaxy formationand evolution scenarios.Some years ago, the hyperleda extragalactic database was designed to study the localuniverse from the point of view of both stellar populations and galaxies kinematics and dynamics.Today it contains homogeneous data for about 3 millions of galaxies,with for each up to 80 astrophysical parameters available.We will describe here the MIGALE project which emcompasses the HyperLeda databases plus aseries of tools developed to study the dynamical, chemical and morphologicalevolution of galaxies. It will include, in particular, methods to analyse theGIRAFFE cosmological fields (IFU spectroscopy) and compare them with the LocalUniverse

Revisiting the optical depth of spiral galaxies using the Tully-Fisher B relation

Aims. We attempt to determine the optical depth of spiral galaxy disks by a statistical study of new Tully-Fisher data from the ongoing KLUN+ survey, and to clarify the difference between the true and apparent behavior of optical depth. Methods. By utilizing so-called normalized distances, a subsample of the data is identified to be as free from selection effects as possible. For these galaxies, a set of apparent quantities are calculated for face-on positions using the Tully-Fisher diameter and magnitude relations. These values are compared with direct observations to determine the mean value of the parameter C describing the optical depth. Results. The present study suggests that spiral galaxy disks are relatively optically thin tauB = 0.1, at least in the outermost regions, while they appear in general to be optically thick tauB > 1 when the apparent magnitude and average surface brightness are studied statistically.Comment: 9 pages, 13 figures, accepted for publication in Astronomy & Astrophysic

Kinematics of the Local Universe XIII. 21-cm line measurements of 452 galaxies with the Nan\c{c}ay radiotelescope, JHK Tully-Fisher relation and preliminary maps of the peculiar velocity field

This paper presents 452 new 21-cm neutral hydrogen line measurements carried out with the FORT receiver of the meridian transit Nan\c{c}ay radiotelescope (NRT) in the period April 2003 -- March 2005. This observational programme is part of a larger project aiming at collecting an exhaustive and magnitude-complete HI extragalactic catalogue for Tully-Fisher applications (the so-called KLUN project, for Kinematics of the Local Universe studies, end in 2008). The whole on-line HI archive of the NRT contains today reduced HI-profiles for ~4500 spiral galaxies of declination delta > -40° (http://klun.obs-nancay.fr). As an example of application, we use direct Tully-Fisher relation in three (JHK) bands in deriving distances to a large catalog of 3126 spiral galaxies distributed through the whole sky and sampling well the radial velocity range between 0 and 8000 km/s. Thanks to an iterative method accounting for selection bias and smoothing effects, we show as a preliminary output a detailed and original map of the velocity field in the Local Universe

La coproduction des oeuvres et de l’atelier par le compositeur (À partir d’une étude de l’activité créatrice de Philippe Leroux entre 2001 et 2006)

Afin d’étudier le processus compositionnel d’un musicien contemporain, Philippe Leroux, les auteurs de cet article ont mis au point un dispositif de recueil de données largement basé sur les éléments de l’atelier du compositeur lors de son travail sur Voi(rex) (2002-2003) puis sur Apocalypsis (2004-2006). Des entretiens de « remise en situation de composition » ont permis de mettre en évidence les principaux documents de travail utilisés par Leroux pour ces oeuvres (esquisses, brouillons, logiciels, etc.) ; leur sollicitation, pendant les entretiens, l’aidait à retrouver des détails précis de son activité passée. Sur cette base, il est possible de caractériser l’atelier en relation avec la dynamique compositionnelle qui l’anime.Cet article recense les éléments constitutifs de l’atelier de Leroux (outils, procédures, ouvrages, partitions d’oeuvres passées) lors de l’écriture des deux oeuvres étudiées, et montre certains types d’usage de ces éléments (opérations de substitution entre éléments, construction de chaînes opératoires). En conséquence, l’atelier est caractérisé à la fois comme le milieu et le produit de la composition. La partition est le lieu de stabilisation de sa dynamique interne, et de résolution de la multiplicité d’outils et procédures partiellement redondants que l’on peut y trouver à tout moment. Ces propositions sont illustrées plus en détail par la reconstitution d’une série d’opérations de composition réalisée au cours de trois semaines de préparation à l’écriture d’Apocalypsis, en mars et avril 2005, ayant débouché entre autres sur le début de l’écriture de l’oeuvre, et sur l’écriture en parallèle d’une brève oeuvre chorale (Thermidor, du cycle Des autres).In order to study the compositional process of contemporary composer Philippe Leroux, the authors compiled an array of information that drew largely on elements from the composer’s workshop during the composition of Voi(rex) (2002-2003) and Apocalypsis (2004-2006). An interview in the form of a compositional situation simulation brought to light the main documents that Leroux used for his work (sketches, early versions, software, etc.); consulting them during the interview process enabled the reclaiming of precise details of the composer’s past activities. Based on this, it was possible to define the composer’s workshop in the context of the compositional dynamic that set it in motion.This article brings together the elements that made up Leroux’s workshop (his tools, procedures, works, scores for earlier works, etc.) as he was writing two specific works, and it reveals how some of these elements may be used (e.g., operations for the substitution of elements and the construction of operation chains). The workshop is thus defined both as the milieu and the product of composition: the score represents the point of stability for its dynamic internal workings, and the resolution of the many tools and somewhat repetitive procedures that might be found at any moment in the work. These ideas are illustrated in greater detail by the reconstitution of a series of compositional operations realized over a period of three weeks, as the composer prepared to write Apocalypsis in March and April of 2005, and after he had set to work on both the beginning of the work and another short choral work (Thermidor from the cycle Des autres)

Kinematics of the local universe IX. The Perseus-Pisces supercluster and the Tolman-Bondi model

We study the mass distribution and the infall pattern of the Perseus-Pisces (PP) supercluster. First we calculate the mass of the central part of PP, a sphere with a radius of 15/h Mpc centered at (l,b)=(140.2\deg ,-22.0\deg), d=50/h Mpc, using the virial and other estimators. We get M_{PP} = 4 -- 7 /h 10^{15} M_{sun}, giving mass-to-light ratio 200 -- 600 h M_{sun} / L_{sun}, and overdensity \delta \approx 4. The radially averaged smoothed density distribution around the PP is inputted to the Tolman-Bondi (TB) equations, calculated for different cosmologies: \Omega_0 = [0.1,1], \Omega_{\Lambda} = 1-\Omega_0 or 0. As a result we get the infall velocities towards the PP center. Comparing the TB results to the peculiar velocities measured for the Kinematics of the Local Universe (KLUN) Tully-Fisher data set we get the best fit for the conditions \Omega_0 = 0.2 -- 0.4 and v_{inf} < 100 km/s for the Local Group infall towards the center of PP. The applicability of the TB method in a complex environment, such as PP, is tested on an N-body simulation.Comment: in press (A&A

A robust method for fitting peculiar velocity field models

We present a new method for fitting peculiar velocity models to complete flux limited magnitude-redshifts catalogues, using the luminosity function of the sources as a distance indicator.The method is characterised by its robustness. In particular, no assumptions are made concerning the spatial distribution of sources and their luminosity function. Moreover, selection effects in redshift are allowed. Furthermore the inclusion of additional observables correlated with the absolute magnitude -- such as for example rotation velocity information as described by the Tully-Fisher relation -- is straightforward. As an illustration of the method, the predicted IRAS peculiar velocity model characterised by the density parameter beta is tested on two samples. The application of our method to the Tully-Fisher MarkIII MAT sample leads to a value of beta=0.6 \pm 0.125, fully consistent with the results obtained previously by the VELMOD and ITF methods on similar datasets. Unlike these methods however, we make a very conservative use of the Tully-Fisher information. Specifically, we require to assume neither the linearity of the Tully-Fisher relation nor a gaussian distribution of its residuals. Moreover, the robustness of the method implies that no Malmquist corrections are required. A second application is carried out, using the fluxes of the IRAS 1.2 Jy sample as the distance indicator. In this case the effective depth of the volume in which the velocity model is compared to the data is almost twice the effective depth of the MarkIII MAT sample. The results suggest that the predicted IRAS velocity model, while successful in reproducing locally the cosmic flow, fails to describe the kinematics on larger scales.Comment: 10 pages, 14 figures, MNRAS in pres