MOSAIX: a tool to built large mosaics from GALEX images

Large sky surveys are providing a huge amount of information for studies of the interstellar medium, the galactic structure or the cosmic web. Setting into a common frame information coming from different wavelengths, over large fields of view, is needed for this kind of research. GALEX is the only nearly all-sky survey at ultraviolet wavelengths and contains fundamental information for all types of studies. GALEX field of view is circular embedded in a squared matrix of 3840 x 3840 pixels. This fact makes it hard to get GALEX images properly overlapped with the existing astronomical tools such as Aladin or Montage. We developed our own software for this purpose. In this article, we describe this software and makes it available to the community.Comment: 7 pages, including 8 figures, accepted by Astrophysics and Space Scienc

Signatures of diffuse interstellar gas in the Galaxy Evolution Explorer all sky survey

The all sky survey run by the Galaxy Evolution Explorer (GALEX AIS) mapped about 85% of the Galaxy at ultraviolet (UV) wavelengths and detected the diffuse UV background produced by the scattering of the radiation from OBA stars by interstellar dust grains. Against this background, diffuse weak structures are detected as well as the UV counterparts to nebulae and molecular clouds. To make full profit of the survey, unsupervised and semi-supervised procedures need to be implemented. The main objective of this work is to implement and analyze the results of the method developed by us for the blind detection of ISM features in the GALEX AIS . Most ISM features are detected at very low signal levels (dark filaments, globules) against the already faint UV background. We have defined an index, the UV background fluctuations index (or UBF index), to identify areas of the sky where these fluctuations are detected. The algorithm is applied to the images obtained in the FUV (1344 -1786 Angstroms) band since this is less polluted by stellar sources, facilitating the automated detection. The UBF index is shown to be sensitive to the main star forming regions within the Gould's Belt, as well as to some prominent loops like Loop I or the Eridanus and Monogem areas. The catalogue with the UBF index values is made available on-line to the community.Comment: The online catalogue will be made available through the CDS services and in the jcuva.ucm.es website. Accepted A&

Procesamiento de la señal ultravioleta para el estudio del medio interestelar (de GALEX a WSO-UV)

El propósito del trabajo aquí presentado es aprovechar al máximo las evidencias que el Medio Interestelar deja en las imágenes ultravioleta. Se ha desarrollado en el marco del proyecto WSO-UV y se han utilizado las imágenes de la misión GALEX. En el Capítulo 4 se presentan dos métodos. El primero (Pair Method en imágenes) está en la base de nuestro estudio y permite tanto realzar la radiación reflejada por las nubes como una estimación aproximada de la Atenuación, medida en magnitud aparente, en los casos donde la nube absorbe la luz. El segundo método se ha presentado públicamente (Tel Aviv, Israel 2017) con el nombre del factor BSVR. Este factor mide el peso que ocupa la información sobre el Medio Interestelar en una imagen determinada, proporcionando al astrónomo un índice del interés para su estudio. Se ha calculado este factor para más de ochenta mil imágenes de GALEX en el rango de ultravioleta lejano y al cotejar los resultados con algunos catálogos recurrentes de la literatura se han constatado varias evidencias detalladas en el último capítulo. Por ejemplo que la contribución del fondo ultravioleta difuso es más importante cuanto más cerca observamos las nubes. El uso en imágenes de las ecuaciones del Pair Method abre las puertas a multitud de trabajos en áreas específicas, permite visualizar las correlaciones reseñadas en la bibliografía entre el ultravioleta y el infrarrojo (a 100μm) y da una dimensión numerable a las evidencias del Medio Interestelar recibidas en ultravioleta. Además el presente trabajo ha hecho públicos tanto los resultados generales como el acceso a las herramientas desarrolladas y otros resultados cualitativos

Experiments about the Generalization Ability of Common Vector based methods for Face Recognition

Abstract. This work presents some preliminary results about exploring and proposing new extensions of common vector based subspace methods that have been recently proposed to deal with very high dimensional classification problems. Both the common vector and the discriminant vector approaches are considered. The different dimensionalities of the subspaces that these methods use as intermediate step are considered in different situations and their relation to the generalization ability of each method is analyzed. Comparative experiments using different databases for the face recognition problem are performed to support the main conclusions of the paper

Developmental control of plant Rho GTPase nano-organization by the lipid phosphatidylserine

International audienceRho GTPases are master regulators of cell signaling, but how they are regulated depending on the cellular context is unclear. Here, we show that the phospholipid phosphatidylserine acts as a 25 developmentally-controlled lipid rheostat that tunes Rho GTPase signaling in Arabidopsis. Live super-resolution single molecule imaging revealed that RHO-OF-PLANT6 (ROP6) is stabilized by phosphatidylserine into plasma membrane nanodomains, which is required for auxin signaling. Furthermore, we uncovered that the plasma membrane phosphatidylserine content varies during plant root development and that the level of phosphatidylserine modulates the quantity of ROP6 30 nanoclusters induced by auxin and hence downstream signaling, including regulation of endocytosis and gravitropism. Our work reveals that variations in phosphatidylserine levels are a physiological process that may be leveraged to regulate small GTPase signaling during development. One Sentence Summary: 35 Phosphatidylserine acts as a developmentally-controlled lipid rheostat that regulates auxin sensitivity and plant development