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

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

Mass-redshift dependency of Supermassive Black Hole Binaries for the Gravitational Wave Background

Studying how the black hole (BH) - (galaxy) bulge mass relation evolves with redshift provides valuable insights into the co-evolution of supermassive black holes and their host galaxies. However, obtaining accurate measurement of BH masses is challenging due to the bias towards the most massive and luminous galaxies. We use an analytical astrophysical model with galaxy stellar mass function, pair fraction, merger timescale and BH-bulge mass relation extended to include redshift evolution. The model can predict the intensity of the gravitational wave background produced by a population of supermassive black hole binary (SMBHB) as a function of the frequency. We focus on the BH-bulge mass relation and its variation with redshift using the EAGLE, Illustris, TNG100, TNG300, Horizon-AGN and SIMBA large-scale cosmological simulations. By understanding the processes and relationships concerning the formation and co-evolution of galaxies and their central BHs we can make theoretical and analytical expressions in order to refine current astrophysical models. This allows us to compare the predictions of this model with the constraints of Pulsar Timing Array observations. Here, we employ Bayesian analysis for the parameter inference. By fitting the BH-bulge mass parameters to the Illustris and SIMBA simulations we analyze the changes in the constraints on the other astrophysical parameters. Furthermore, we also examine the variation in SMBHB merger rate with mass and redshift between these large-scale simulations.Comment: 17 pages, 13 figures, 5 tables, 23 appendix figure

Kinematics of the Local Universe XIII. 21-cm line measurements of 452 galaxies with the Nançay radiotelescope, JHK Tully-Fisher relation and preliminary maps of the peculiar velocity field

International audienceThis paper presents 452 new 21-cm neutral hydrogen line measurements carried out with the FORT receiver of the meridian transit Nançay 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

Rfi Mitigation Implementation For Pulsar Radioastronomy

International audienceThe observation of known pulsars (pulsar timing) or the search for new pulsars can be limited by radio frequency interference (RFI) generated by Telecommunications activity. In this paper we propose several RFI mitigation techniques to cope with impulsive and/or narrow band RFI. For pulsar timing, we have implemented, a pulse blanker and a cyclostationary blanker,both in real time. Exemple with real data are shown. For pulsar search, we propose a new approach which combines a hardware-efficient search method and some RFI mitigation capabilities. This method is based on a 2D FFT and Radon transform

Détection Aveugle de Pulses Géants : Implantation sur GPU

National audienceL'observation radio des Pulsars nécessite une instrumentation spécifique et des procédures de traitement du signal dédiées qui corrigent les effets de la dispersion induite par le milieu interstellaire. En outre, la qualité des observations peut être notablement dégradée par la présence d'interférences radioélectriques (RFI) d'origine anthropique. Ce papier présente l'instrumentation mise en place pour l'observation des pulsars à la Station de Radioastronomie de Nançay. Notamment, nous détaillerons une approche originale pour la détection automatique de pulses géants. Bien que moins sensible que l'approche classique consistant à balayer en temps différé l'espace des paramètres du pulsar potentiel, l'approche proposée se distingue par une efficacité d'implantation, une capacité de traitement en temps réel et une robustesse intrinsèque aux RFI. En outre, elle ne nécessite aucune connaissance préalable des paramètres du pulsar, ce qui autorise son utilisation pour la détection d'événements impulsionnels non répertoriés. Une implantation sur GPU est en cours de validation

Blind detection of giant pulses: GPU implementation

International audienceRadio astronomical pulsar observations require specific instrumentation and dedicated signal processing to cope with the dispersion caused by the interstellar medium. Moreover, the quality of observations can be limited by radio frequency interference (RFI) generated by Telecommunications activity. This article presents the innovative pulsar instrumentation based on graphical processing units (GPU) which has been designed at the Nançay Radio Astronomical Observatory. In addition, for giant pulsar search, we propose a new approach which combines a hardware-efficient search method and some RFI mitigation capabilities. Although this approach is less sensitive than the classical approach, its advantage is that no a priori information on the pulsar parameters is required. The validation of a GPU implementation is under way

RFI mitigation at Nanc¸ay Observatory: Impulsive Signal Processing

Radio astronomy has protected frequency bands for free observations. However, it is often necessary to observe outside of those sanctuaries. For example, it is the case for HI radio-sources with high red-shifts that are observed into radarallocated frequency bands. A radar pulse blanker based on statistical analysis has been implemented in a FPGA. Several tricks has made the implementation possible at a low hardware cost. Pulsar is another kind of impulsive signal which needs specific processing. In the proposed approach, the cyclostationarity is used to discriminate between radio-frequency interference (RFI) pulses and pulsar pulses

The INPOP10a planetary ephemeris and its applications in fundamental physics

International audienceCompared to the previous INPOP versions, the INPOP10a planetary and lunar ephemeris has several improvements. For the planets of our solar system, no big change was brought in the dynamics but improvements were implemented in the fitting process, the data sets used in the fit and in the selection of fitted parameters. We report here the main characteristics of the planetary part of INPOP10a like the fit of the product of the Solar mass with the gravitational constant (GM$_{\odot}$) instead of the astronomical unit. Determinations of PPN parameters as well as adjustments of the Sun J2 and of asteroid masses are also presented. New advances of nodes and perihelia of planets were also estimated and are given here. As for INPOP08, INPOP10a provides to the user, positions and velocities of the planets, the moon, the rotation angles of the Earth and the Moon as well as TT-TDB chebychev polynomials at http://www.imcce.fr/inpo