The Dark Energy Survey : more than dark energy – an overview

This overview paper describes the legacy prospect and discovery potential of the Dark Energy Survey (DES) beyond cosmological studies, illustrating it with examples from the DES early data. DES is using a wide-field camera (DECam) on the 4 m Blanco Telescope in Chile to image 5000 sq deg of the sky in five filters (grizY). By its completion, the survey is expected to have generated a catalogue of 300 million galaxies with photometric redshifts and 100 million stars. In addition, a time-domain survey search over 27 sq deg is expected to yield a sample of thousands of Type Ia supernovae and other transients. The main goals of DES are to characterize dark energy and dark matter, and to test alternative models of gravity; these goals will be pursued by studying large-scale structure, cluster counts, weak gravitational lensing and Type Ia supernovae. However, DES also provides a rich data set which allows us to study many other aspects of astrophysics. In this paper, we focus on additional science with DES, emphasizing areas where the survey makes a difference with respect to other current surveys. The paper illustrates, using early data (from ‘Science Verification’, and from the first, second and third seasons of observations), what DES can tell us about the Solar system, the Milky Way, galaxy evolution, quasars and other topics. In addition, we show that if the cosmological model is assumed to be +cold dark matter, then important astrophysics can be deduced from the primary DES probes. Highlights from DES early data include the discovery of 34 trans-Neptunian objects, 17 dwarf satellites of the Milky Way, one published z > 6 quasar (and more confirmed) and two published superluminous supernovae (and more confirmed)

Institutions financières, allocation du crédit et marginalisation dans le Nord-Est du Brésil : L’exemple de Bahia

Cet article constitue une étude empirique des pratiques discriminatoires imposées par les banques à la bourgeoisie industrielle et à leurs entreprises dans l'État du Nord-Est du Brésil qui se développe aujourd'hui le plus vite. Fondé sur une enquête par interviews auprès d'un échantillon aléatoire et systématique des dirigeants des plus grandes entreprises, ainsi que sur des données statistiques provenant des archives gouvernementales et bancaires cet essai établit l'histoire économique et politique de cet État et les problèmes qui ont entravé son émergence. Une analyse des opérations de crédit, des emprunts à court et à long terme, et de taux d'intérêts montre que les banques d'État, en particulier la Banque du Brésil, marginalisent la bourgeoisie industrielle associée aux secteurs économiques traditionnels et aux entreprises familiales. Elles appuient, par contre, les dirigeants des firmes nouvelles, à haute intensité de capital qui sont souvent des filiales de grands conglomérats nationaux ou internationaux. L'une des conséquences inattendues de l'intervention de l'État et de l'hégémonie du capital financier est la pénétration du capital étranger dans les secteurs à haute intensité de capital. Ceci peut éroder le soutien et le sacrifice populaires sur lesquels le régime compte pour poursuivre son miracle économique. Cet essai montre ainsi comment les institutions clés sont utilisées par l'État pour stratifier et contrôler les classes sociales dans une des zones au développement le plus rapide en Amérique latine et peut être dans le Tiers Monde.This is an empirical study of discriminatory practices imposed by banks on the industrial bourgoisie and their enterprises in Bahia, the most rapidly developing state in the Northeast of Brazil. Based on a systematic, random (interview) survey of the largest manufacturers and statistical data from banking and governmental archives, the essay establishes the political and economic history of the state and the problems which hindered its emergence. An analysis of credit transactions, short and long term borrowing, and interest rates shows that state banks, particularly the Bank of Brazil, marginalized the industrial bourgoisie associated with traditional economies and family-owned enterprises but endorsed those heading the newer, capital-intensive, often subsidiary of a larger national or international conglomerate. One unintended consequence of state intervention and hege-monization of finance capital is the penetration of foreign capital into labor intensive sectors. This could erode the popular support and sacrifice on which the regime relies to continue its economic miracle. Here is an essay which illustrates how key institutions are used by the State to stratify and control social classes in the most rapidly developing areas in Latin America, if not the Third World.Este articulo constituye un estudio empírico de las practicas discriminatorias impuestas por las banca:; a la burguesía industrial y a sus empresas en el Estado del Nord Este del Brasil que hoy día se desarrolla rápidamente. Fundado sobre una encuesta por entrevistas según una muestra aleatoria y sistemática de dirigentes de las empresas más grandes, asi que sobre datos estadísticos que vienen de los archivos guvemamentales y bancarios, este ensayo establece la historia económica y política de este Estado y los problemas que han estorbado su emergencia. Un análisis de las operaciones de crédito, de prestamos a corto y largo plazo, y las tasas de interés, muestra que las bancos del Estado, en particular El Banco del Brasil, marginalisan la burguesía industrial asociada a los sectores económicos tradicionales y a las empresas familiares. Ellas apoyan en cambio los dirigentes de nuevas firmas, a alta intensidad de capital que son a menudo filiales de los más grandes conglomerados nationales o internacionales. Una de las consecuencias inesperadas de la intervención del Estado y de la hegemonía del capital financiero es la penetración del capital estranjero en los sectores a alta intensidad de capital. Esto puede corroer el apoyo y el sacrificio popular sobre los cuales el régimen cuenta para continuar su milagro económico Este ensayo muestra de esta manera como las instituciones claves son utilisadas por el Estado para estratificar y controlar las clases sociales en las zonas de desarrollo más intensas en América-Latina y a lo mejor del Tercer Mundo

Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

We measure the weak lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey (DES). This pathfinder study is meant to (1) validate the Dark Energy Camera (DECam) imager for the task of measuring weak lensing shapes, and (2) utilize DECam’s large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, point spread function (PSF) modelling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well behaved, but the modelling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster–galaxy distributions. By fitting Navarro–Frenk–White profiles to the clusters in this study, we determine weak lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak lensing mass, and richness. In addition, the cluster–galaxy distributions indicate the presence of filamentary structures attached to 1E 0657−56 and RXC J2248.7−4431, stretching out as far as 1◦(approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky

Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

We measure the weak lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey (DES). This pathfinder study is meant to (1) validate the Dark Energy Camera (DECam) imager for the task of measuring weak lensing shapes, and (2) utilize DECam’s large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, point spread function (PSF) modelling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well behaved, but the modelling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster–galaxy distributions. By fitting Navarro–Frenk–White profiles to the clusters in this study, we determine weak lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak lensing mass, and richness. In addition, the cluster–galaxy distributions indicate the presence of filamentary structures attached to 1E 0657−56 and RXC J2248.7−4431, stretching out as far as 1◦(approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky