Southern Cosmology Survey III: QSO's from Combined GALEX and Optical Photometry

We present catalogs of QSO candidates selected using photometry from GALEX combined with SDSS in the Stripe 82 region and Blanco Cosmology Survey (BCS) near declination -55 degrees. The SDSS region contains ~700 objects with magnitude i < 20 and ~3600 objects with i < 21.5 in a ~60 square degree sky region, while the BCS region contains ~280 objects with magnitude i < 20 and ~2000 objects with i < 21.5 for a 11 square degree sky region that is being observed by three current microwave Sunyaev-Zeldovich surveys. Our QSO catalog is the first one in the BCS region. Deep GALEX exposures (~2000 seconds in FUV and NUV, except in three fields) provide high signal-to-noise photometry in the GALEX bands (FUV, NUV < 24.5 mag). From this data, we select QSO candidates using only GALEX and optical r-band photometry, using the method given by Atlee and Gould (2008). In the Stripe 82 field, 60% (30%) of the GALEX selected QSO's with optical magnitude i<20 (i<21.5) also appear in the Richards et al. (2008) QSO catalog constructed using 5-band optical SDSS photometry. Comparison with the same catalog by Richards et al. shows that the completeness of the sample is approximately 40%(25%). However, for regions of the sky with very low dust extinction, like the BCS 23hr field and the Stripe 82 between 0 and 10 degrees in RA, our completeness is close to 95%, demonstrating that deep GALEX observations are almost as efficient as multi-wavelength observations at finding QSO's. GALEX observations thus provide a viable alternate route to QSO catalogs in sky regions where u-band optical photometry is not available. The full catalog is available at http://www.ice.csic.es/personal/jimenez/PHOTOZComment: Submitted to ApJ

All sky CMB map from cosmic strings integrated Sachs-Wolfe effect

By actively distorting the Cosmic Microwave Background (CMB) over our past light cone, cosmic strings are unavoidable sources of non-Gaussianity. Developing optimal estimators able to disambiguate a string signal from the primordial type of non-Gaussianity requires calibration over synthetic full sky CMB maps, which till now had been numerically unachievable at the resolution of modern experiments. In this paper, we provide the first high resolution full sky CMB map of the temperature anisotropies induced by a network of cosmic strings since the recombination. The map has about 200 million sub-arcminute pixels in the healpix format which is the standard in use for CMB analyses (Nside=4096). This premiere required about 800,000 cpu hours; it has been generated by using a massively parallel ray tracing method piercing through a thousands of state of art Nambu-Goto cosmic string numerical simulations which pave the comoving volume between the observer and the last scattering surface. We explicitly show how this map corrects previous results derived in the flat sky approximation, while remaining completely compatible at the smallest scales.Comment: 8 pages, 4 figures, uses RevTeX. References added, matches published versio

Visualizing probabilistic models: Intensive Principal Component Analysis

Unsupervised learning makes manifest the underlying structure of data without curated training and specific problem definitions. However, the inference of relationships between data points is frustrated by the `curse of dimensionality' in high-dimensions. Inspired by replica theory from statistical mechanics, we consider replicas of the system to tune the dimensionality and take the limit as the number of replicas goes to zero. The result is the intensive embedding, which is not only isometric (preserving local distances) but allows global structure to be more transparently visualized. We develop the Intensive Principal Component Analysis (InPCA) and demonstrate clear improvements in visualizations of the Ising model of magnetic spins, a neural network, and the dark energy cold dark matter ({\Lambda}CDM) model as applied to the Cosmic Microwave Background.Comment: 6 pages, 5 figure

Improving Photometric Redshifts using GALEX Observations for the SDSS Stripe 82 and the Next Generation of SZ Cluster Surveys

Four large-area Sunyaev-Zeldovich (SZ) experiments -- APEX-SZ, SPT, ACT, and Planck -- promise to detect clusters of galaxies through the distortion of Cosmic Microwave Background photons by hot (> 10^6 K) cluster gas (the SZ effect) over thousands of square degrees. A large observational follow-up effort to obtain redshifts for these SZ-detected clusters is under way. Given the large area covered by these surveys, most of the redshifts will be obtained via the photometric redshift (photo-z) technique. Here we demonstrate, in an application using ~3000 SDSS stripe 82 galaxies with r<20, how the addition of GALEX photometry (FUV, NUV) greatly improves the photometric redshifts of galaxies obtained with optical griz or ugriz photometry. In the case where large spectroscopic training sets are available, empirical neural-network-based techniques (e.g., ANNz) can yield a photo-z scatter of $\sigma_z = 0.018 (1+z)$. If large spectroscopic training sets are not available, the addition of GALEX data makes possible the use simple maximum likelihood techniques, without resorting to Bayesian priors, and obtains $\sigma_z=0.04(1+z)$, accuracy that approaches the accuracy obtained using spectroscopic training of neural networks on ugriz observations. This improvement is especially notable for blue galaxies. To achieve these results, we have developed a new set of high resolution spectral templates based on physical information about the star formation history of galaxies. We envision these templates to be useful for the next generation of photo-z applications. We make our spectral templates and new photo-z catalogs available to the community at http://www.ice.csic.es/personal/jimenez/PHOTOZ .Comment: 10 pages, 8 figure

Schutzfaktoren bei Kindern vor dem Übergang in die Sekundarstufe - Ergebnisse aus der STRESS-Studie

Der Übergang in die Sekundarstufe stellt für Kinder ein normativ kritisches Lebensereignis dar, das unterschiedlich bewertet und bewältigt wird. Der vorliegende Beitrag befasst sich mit der Frage, welche Schutzfaktoren dazu beitragen, dass Kinder dem Übergang mit Gefühlen der Vorfreude begegnen und sie dieses Ereignis problemorientiert bewältigen. Untersucht werden 596 ViertklässlerInnen aus Bayern und Hessen vor dem Übergang in die Sekundarstufe. In Anlehnung an die kognitiv-transaktionale Theorie von Lazarus und Folkman (1984) werden die Zusammenhänge von primärer Bewertung als Herausforderung und problemorientierter Stressbewältigung unter Berücksichtigung von personalen (akademisches Selbstkonzept, Selbstwirksamkeit) und sozialen Schutzfaktoren (Familienzusammenhalt, allgemeines förderndes Elternverhalten) analysiert. Mithilfe von Strukturgleichungsmodellen lassen sich Mediationseffekte der Schutzfaktoren nachweisen. Insbesondere das akademische Selbstkonzept und ein förderliches Familienumfeld erweisen sich als bedeutsame protektive Faktoren in der Phase vor dem Übergang.Transition to secondary school constitutes a normative critical life event for children, which is evaluated and managed individually. The present study focuses on the role of protective factors helping children to approach this transition with emotions of pleasant anticipation and problem-focused coping. 596 fourth graders from Bavaria and Hesse were examined prior to their transition to secondary school. Referring to the cognitive-transactional theory from Lazarus and Folkman (1984), correlations between primary appraisal as a challenge and problem-focused coping in consideration of personal (academic self-concept, self-efficacy) and social protective factors (family cohesion, general supportive parent behavior) have been analyzed. Using structural equation models, the mediation effects of protective factors can be confirmed. Academic self-concept and a supportive family environment particularly proved to be protective factors prior to the transition

The effectiveness of the clean development mechanism and emissions trading within the climate change regime

This research evaluates the effectiveness of the climate change regime within South Africa, focusing on the implementation of the Flexible Mechanisms of the United Nations Kyoto Protocol. The two flexible mechanisms are the Clean Development Mechanism and Emissions Trading. Regime effectiveness is the dominant analytical approach to understanding and evaluating the effectiveness of international environmental agreements. Various methods of evaluating regime effectiveness have emerged in the past two-three decades, and this research adapts these methods to the South African context. Regime effectiveness as an approach is used to inform the inputs of institutional design, as well as regular reviewing and changes of the institutional design. This in turn influences a state’s stance on international cooperation in a given issue-area. The problems, successes and weaknesses that emerge from the South African CDM project case-studies are evaluated against the adapted framework for domestic regime effectiveness, and the findings and recommendations presented in the concluding chapter

Advanced code-division multiplexers for superconducting detector arrays

Multiplexers based on the modulation of superconducting quantum interference devices are now regularly used in multi-kilopixel arrays of superconducting detectors for astrophysics, cosmology, and materials analysis. Over the next decade, much larger arrays will be needed. These larger arrays require new modulation techniques and compact multiplexer elements that fit within each pixel. We present a new in-focal-plane code-division multiplexer that provides multiplexing elements with the required scalability. This code-division multiplexer uses compact lithographic modulation elements that simultaneously multiplex both signal outputs and superconducting transition-edge sensor (TES) detector bias voltages. It eliminates the shunt resistor used to voltage bias TES detectors, greatly reduces power dissipation, allows different dc bias voltages for each TES, and makes all elements sufficiently compact to fit inside the detector pixel area. These in-focal-plane code-division multiplexers can be combined with multi-gigahertz readout based on superconducting microresonators to scale to even larger arrays.Comment: 8 pages, 3 figures, presented at the 14th International Workshop on Low Temperature Detectors, Heidelberg University, August 1-5, 2011, proceedings to be published in the Journal of Low Temperature Physic