Constraining the photometric properties of MgII absorbing galaxies with the SDSS

Using a sample of nearly 700 quasars with strong (W_0(2796)>0.8 Angstrom) MgII absorption lines detected in the Early Data Release of the SDSS, we demonstrate the feasibility of measuring the photometric properties of the absorber systems by stacking SDSS imaging data. As MgII lines can be observed in the range 0.37<z_abs<2.2, the absorbing galaxies are in general not identified in SDSS images, but they produce systematic light excesses around QSOs which can be detected with a statistical analysis. In this Letter we present a 6-sigma detection of this effect over the whole sample in i-band, rising to 9.4-sigma for a low-redshift subsample with 0.37<z_abs<=0.82. We use a control sample of QSOs without strong MgII absorption lines to quantify and remove systematics with typical 10-20% accuracy. The signal varies as expected as a function of absorber redshift. For the low z_abs subsample we can reliably estimate the average luminosities per MgII absorber system in the g, r, and i bands and find them to be compatible with a few-hundred-Myr old stellar population of M_r ~ -21 in the rest frame. Colors are also consistent with typical absorbing galaxies resembling local Sb-c spirals. Our technique does not require any spectroscopic follow-up and does not suffer from confusion with other galaxies arising along the line-of-sight. It will be applied to larger samples and other line species in upcoming studies.Comment: Accepted on ApJ Letters, 5 pages, 2 figure

Hydrogen Emission from the Ionized Gaseous Halos of Low Redshift Galaxies

Using a sample of nearly half million galaxies, intersected by over 7 million lines of sight from the Sloan Digital Sky Survey Data Release 12, we trace H$\alpha$ + [N{\small II}] emission from a galactocentric projected radius, $r_p$, of 5 kpc to more than 100 kpc. The emission flux surface brightness is $\propto r_p^{-1.9 \pm 0.4}$. We obtain consistent results using only the H$\alpha$ or [N{\small II}] flux. We measure a stronger signal for the bluer half of the target sample than for the redder half on small scales, $r_p <$ 20 kpc. We obtain a $3\sigma$ detection of H$\alpha$ + [N{\small II}] emission in the 50 to 100 kpc $r_p$ bin. The mean emission flux within this bin is $(1.10 \pm 0.35) \times 10^{-20}$ erg cm$^{-2}$ s$^{-1}$ \AA$^{-1}$, which corresponds to $1.87 \times 10^{-20}$ erg cm$^{-2}$ s$^{-1}$ arcsec$^{-2}$ or 0.0033 Rayleigh. This detection is 34 times fainter than a previous strict limit obtained using deep narrow-band imaging. The faintness of the signal demonstrates why it has been so difficult to trace recombination radiation out to large radii around galaxies. This signal, combined with published estimates of n$_{\rm H}$, lead us to estimate the temperature of the gas to be 12,000 K, consistent with independent empirical estimates based on metal ion absorption lines and expectations from numerical simulations.Comment: 12 pages, 13 figure

Effect of dipolar interactions on cavity magnon-polaritons

The strong photon-magnon coupling between an electromagnetic cavity and two yttrium iron garnet (YIG) spheres has been investigated in the context of a strong mutual dipolar interaction between the spheres. A decrease in the coupling strength between the YIG spheres and the electromagnetic cavity is observed, along with an increase of the total magnetic losses, as the distance between the spheres is decreased. A model of inhomogeneous broadening of the ferromagnetic resonance linewidth, partly mitigated by the dipolar narrowing effect, reproduces the reduction in the coupling strength observed experimentally. These findings have important implications for the understanding of strongly coupled photon-magnon system involving densely packed magnetic objects, such as ferromagnetic nanowires arrays, in which the total coupling strength with an electromagnetic cavity might become limited due to mutual dipolar interactions.Comment: 5 pages, 5 figure

Génération d'animations par capture de mouvements avec multiples caméras 3D

RÉSUMÉ Le présent mémoire traite du sujet de la capture de mouvement par caméra de profondeur. Plus précisément, la recherche émet l’hypothèse que la capture de mouvement produite par une simple caméra 3D peut être améliorée en intégrant multiples caméras et un système de cinématique inverse dans une solution de capture complète. La solution produite intègre plusieurs composantes indépendantes, qui intègrent le modèle humain de la bibliothèque HumanIK d’Autodesk dans un système de capture utilisant multiples caméras Kinect. Une architecture client-serveur est utilisée afin de combiner les données de multiples caméras 3D, en transformant le système de coordonnées de chacune d’elle dans une référence centrale. Nous établissons qu’un maximum de 3 caméras peuvent être utilisées simultanément, et procédons ensuite à combiner les squelettes en effectuant une moyenne intelligente sur les donnes accumulées. La bibliothèque de cinématique inverse est ensuite intégrée au système. Plusieurs possibilités d’intégration sont explorées et mesurées. Finalement, l’application de la cinématique inverse après la capture du squelette à chaque trame est retenue comme étant la méthode la plus précise. De plus, toutes les fonctions dérivées de la cinématique inverse, tel que les limites de flexibilité du corps humain et la correction de poses sont retenues dans la solution, car elles améliorent significativement la qualité des séquences. Finalement, de l’information supplémentaire pour compléter la cinématique inverse est recherchée dans les images de profondeur. De l’information sur l’état des mains du sujet et sur l’orientation de la tête est extraite et intégrée dans le modèle humain de HumanIK. Avec une analyse quantitative et qualitative de chaque composante indépendante et combinée, la recherche montre que la séquence de mouvement finale produite montre une amélioration significative par rapport à une simple capture par caméra 3D. Malgré les résultats montrant une amélioration significative des captures produites, celles-ci demeurent de qualité insuffisante afin d’être utilisées dans un contexte pratique. Par contre, l’intégration de la recherche dans le logiciel Motion Builder d’Autodesk a été faite et montre un potentiel et une grande attente par rapport à la capture de mouvement par caméra 3D.----------ABSTRACT This research looks to enhance the quality of motion capture generated by a single depth camera. It suggests that by using multiple Kinect cameras as input and combining a human model of inverse kinematics, a motion sequence can be significantly improved. The first step into producing the proposed solution aims to reconcile the data from multiple depth cameras. These cameras are active sensors and interfere with each other, so that their use is limited. We establish that a higher limit of 3 cameras can be used simultaneously in our conditions and proceed to combine their data into a single output skeleton. By converting each cameras transformation space into a centralized reference, we can perform a smart average on each skeleton and use the resulting data as a basis on which to apply the inverse kinematics integration. Using the HumanIK library by Autodesk, the research then explores multiples ways of integrating an inverse kinematics solution into the motion capture pipeline. We determine that applying the kinematic equations after each pose has been calculated at each frame produces the best results. Furthermore, each function offered by HumanIK, derived from inverted kinematics applied to a human model, is analyzed. We find that all the functions, such as human flexibility models and pose correction, have benefits on the resulting sequence of movements. Finally, we look for additional data in the depth images to enhance the information fed to our IK model. By extracting hand states and head position and rotation, we can use HumanIK to calculate and guess at these values, significantly enhancing the quality of the produced MoCap sequences. We finally perform both quantitative and qualitative measurements. To do so, we compare our results with a commercial Flock Of Birds system and use a group of individuals to perform a blind test on resulting animations. We find that we can significantly enhance both the accuracy and quality of animation produced compared to that produced with a single depth camera. Despite the results being significantly better, the animations created are still not to a quality standard that can be used in a production pipeline. Despite this, the solution has been integrated in Autodesk Motion Builder software showing big promise, potential and expectancy towards depth camera based motion capture

Modélisation de la magnétoimpédance géante dans les conducteurs magnétiques cylindriques

Théorie de la magnétoimpédance dans les fils magnétiques -- Structure magnétique -- Relations de dispersion -- IMpédance d'un conducteur cylindrique anisotrope -- Solution générale -- Discussion et simplification de la théorie -- De la théorie à l'expérience -- Fils amorphes de CoFeSiB -- Magnétoimpédance géante et résonance ferromagnétique

Epitaxial thin films of multiferroic Bi2FeCrO6 with B-site cationic order

Epitaxial thin films of Bi2FeCrO6 have been synthesized by pulsed laser deposition on SrRuO3 on (100)- and (111)-oriented SrTiO3 substrates. Detailed X-ray diffraction and cross-section transmission electron microscopy analysis revealed a double perovskite crystal structure of the Bi2FeCrO6 epitaxial films very similar to that of BiFeO3 along with a particularly noteworthy Fe3+/Cr3+ cation ordering along the [111] direction. The films contain no detectable magnetic iron oxide impurities and have the correct cationic average stoichiometry throughout their thickness. They however exhibit a slight modulation in the Fe and Cr compositions forming complementary stripe patterns, suggesting minor local excess or depletion of Fe and Cr. The epitaxial BFCO films exhibit good ferroelectric and piezoelectric properties, in addition to magnetic properties at room temperature, as well as an unexpected crystallographic orientation dependence of their room temperature magnetic properties. Our results qualitatively confirm the predictions made using the ab-initio calculations: the double-perovskite structure of Bi2FeCrO6 films exhibit a Fe3+/Cr3+ cation ordering and good multiferroic properties, along with the unpredicted existence of magnetic ordering at room temperature.Comment: Accepted for publication in Journal of Materials Researc

Die Begrenzung der Wissensfelder bei Kant, Canguilhem und Foucault

Mit ihrer Forderung nach einer Situierung des Wissens kritisiert Donna J. Haraway den Anspruch der Wissenschaften, insbesondere der Biologie, ubiquitäre Erkenntnisse zu liefern, deren universeller Wert eben von dieser Ubiquität abhängt. Wenn ich im Folgenden deutlich machen werde, was die drei im Titel dieses Beitrags genannten Autoren miteinander verbindet, möchte ich damit für eine Regionalität des Wissens eintreten, die sich mit Haraways Position deckt und zugleich von ihr unterscheidet

Strella

Como parte de las actividades académicas realizadas por Monique David-Ménard durante su visita a Buenos Aires en Octubre 2015, tuvo lugar la proyección y debate de un film. Se trata de la película griega Strella (Panos H. Koutras, 2009) sugerida por la propia David-Ménard y por el psicoanalista argentino residente en Paris Horacio Amigorena. Este artículo incluye la primera parte de la discusión, reservando la continuación para el número de Marzo 2016. Luego de una introducción argumental del film, se recorren los diferentes temas que promueve la historia: incesto, transexualismo, función paterna, farsa, ficción, nuevas sexualidades y configuraciones familiares. La historia está narrada a la manera de una moderna tragedia griega en torno a una pregunta crucial ¿es posible recomponer el vínculo entre un padre y un hijo a partir de una historia ominosa

Conatus und Lebensnot

Anders als Simondon waren Lacan und Laplanche von einer epistemologischen Orientierung geprägt, die sie mit Bachelard, Koyré, Althusser und Foucault verband und die als Methode der »ruptures épistémologiques« beschrieben werden kann. Aus dieser Perspektive kann keine Homogenität zwischen den Wissenschaften des Lebens, der Technik und der Psyche konstruiert werden. Ist es möglich, dass eine Orientierung der Psychoanalyse an der Methode der »ruptures épistémologiques« mit der Medienwissenschaft ins Gespräch kommt und dass sie sich in dieser Auseinandersetzung erneuert? Diese Frage steht im Hintergrund, wenn ich im Folgenden über die Konzepte Conatus und Lebensnot nachdenke