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Heliophysics data analysis often involves combining diverse science measurements, many of them captured as time series. Although there are now only a few commonly used data file formats, the diversity in mechanisms for automated access to and aggregation of such data holdings can make analysis that requires intercomparison of data from multiple data providers difficult. The Heliophysics Application Programmer's Interface (HAPI) is a recently developed standard for accessing distributed time series data to increase interoperability. The HAPI specification is based on the common elements of existing data services, and it standardizes the two main parts of a data service: the request interface and the response data structures. The interface is based on the REpresentational State Transfer (REST) or RESTful architecture style, and the HAPI specification defines five required REST endpoints. Data are returned via a streaming format that hides file boundaries; the metadata is detailed enough for the content to be scientifically useful, e.g., plotted with appropriate axes layout, units, and labels. Multiple mature HAPI‐related open‐source projects offer server‐side implementation tools and client‐side libraries for reading HAPI data in multiple languages (IDL, Java, MATLAB, and Python). Multiple data providers in the US and Europe have added HAPI access alongside their existing interfaces. Based on this experience, data can be served via HAPI with little or no information loss compared to similar existing web interfaces. Finally, HAPI has been recommended as a COSPAR standard for time series data delivery. Plain Language Summary: The Heliophysics Application Programmer's Interface (HAPI) specification allows data providers to use a standard set of conventions for returning data in response to a URL‐based request. This specification was developed because no standard exists. Data providers use incompatible conventions so that automated access to and aggregation of data requires users to write custom code for each data provider. The benefit to the user is that software libraries for many common languages have been developed to read HAPI data; if a data provider serves data using the HAPI specification, the user does not need to write additional code to access the data. The starting point for using and learning more about HAPI is http://hapi-server.org/. Key Points: HAPI was developed because there are many nonstandard approaches to serving Heliophysics time series dataHAPI provides a standard specification that will simplify data accessSoftware libraries for downloading data from HAPI servers in many commonly used programming languages are available [ABSTRACT FROM AUTHOR]

The flexible interchange transport system (FITS) file format has become the de facto standard for sharing, analyzing, and archiving astronomical data over the last four decades. FITS was adopted by astronomers in the early 1980s to overcome incompatibilities between operating systems. On the back of FITS' success, astronomical data became both backward compatible and easily shareable. However, new advances in the astronomical instrumentation, computational technologies, and analytic techniques have resulted in new data that do not work well within the traditional FITS format. Tensions have arisen between the desire to update the format to meet new analytic challenges and adherence to the original edict for the FITS file format to be backward compatible. We examine three inflection points in the governance of FITS: first, initial development and success, second, widespread acceptance and governance by the working group, and third, the challenges to FITS in a new era of increasing data and computational complexity within astronomy. [ABSTRACT FROM AUTHOR]

The present work aims at developing two LC-HRMS setups for the screening of organic matter in astrophysical samples. Their analytical development has been demonstrated on a 100-µg residue coming from the photo-thermo chemical processing of a cometary ice analog produced in laboratory. The first 1D-LC-HRMS setup combines a serially coupled columns configuration with HRMS detection. It has allowed to discriminate among different chemical families (amino acids, sugars, nucleobases and oligopeptides) in only one chromatographic run without neither a priori acid hydrolysis nor chemical derivatisation. The second setup is a dual-LC configuration which connects a series of trapping columns with analytical reverse-phase columns. By coupling on-line these two distinct LC units with a HRMS detection, high mass compounds (350 < m/z < 600) have been efficiently preconcentrated, separated and detected. Our strategies demonstrate a real interest for the analysis of astrophysical samples coming in minute quantities and allowing only few analytical runs. Besides its relevance for astrobiological studies, this work points out the suitability of these two novel LC-HRMS strategies for untargeted analysis of complex environmental samples. [ABSTRACT FROM AUTHOR]

Variability Search Toolkit (VaST) is a software package designed to find variable objects in a series of sky images. It can be run from a script or interactively using its graphical interface. VaST relies on source list matching as opposed to image subtraction. SExtractor is used to generate source lists and perform aperture or PSF-fitting photometry (with PSFEx). Variability indices that characterize scatter and smoothness of a lightcurve are computed for all objects. Candidate variables are identified as objects having high variability index values compared to other objects of similar brightness. The two distinguishing features of VaST are its ability to perform accurate aperture photometry of images obtained with non-linear detectors and handle complex image distortions. The software has been successfully applied to images obtained with telescopes ranging from 0.08 to 2.5 m in diameter equipped with a variety of detectors including CCD, CMOS, MIC and photographic plates. About 1800 variable stars have been discovered with VaST. It is used as a transient detection engine in the New Milky Way (NMW) nova patrol. The code is written in C and can be easily compiled on the majority of UNIX-like systems. VaST is free software available at http://scan.sai.msu.ru/vast/ . [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) modelling is more than just good fun, it offers a new vehicle to represent and understand scientific data and gives experts and non-experts alike the ability to manipulate models and gain new perspectives on data. This article explores the use of 3D modelling and printing in astronomy and astronomy communication and looks at some of the practical challenges, and solutions, to using 3D modelling, visualisation and printing in this way. [ABSTRACT FROM AUTHOR]

Purpose This paper aims to focus on the assessment of the ability of computer models with imperfect functional forms and uncertain input parameters to represent reality.Design/methodology/approach In this assessment, both the agreement between a model’s predictions and available experiments and the robustness of this agreement to uncertainty have been evaluated. The concept of satisfying boundaries to represent input parameter sets that yield model predictions with acceptable fidelity to observed experiments has been introduced.Findings Satisfying boundaries provide several useful indicators for model assessment, and when calculated for varying fidelity thresholds and input parameter uncertainties, reveal the trade-off between the robustness to uncertainty in model parameters, the threshold for satisfactory fidelity and the probability of satisfying the given fidelity threshold. Using a controlled case-study example, important modeling decisions such as acceptable level of uncertainty, fidelity requirements and resource allocation for additional experiments are shown.Originality/value Traditional methods of model assessment are solely based on fidelity to experiments, leading to a single parameter set that is considered fidelity-optimal, which essentially represents the values which yield the optimal compensation between various sources of errors and uncertainties. Rather than maximizing fidelity, this study advocates for basing model assessment on the model’s ability to satisfy a required fidelity (or error tolerance). Evaluating the trade-off between error tolerance, parameter uncertainty and probability of satisfying this predefined error threshold provides us with a powerful tool for model assessment and resource allocation. [ABSTRACT FROM AUTHOR]

I examine differences in non-linear structure formation between cosmological models that share a z=0 linear power spectrum in both shape and amplitude, but that differ via their growth history. N-body simulations of these models display an approximately identical large-scalestructure skeleton, but reveal deeply non-linear differences in the demographics and properties of haloes. I investigate to what extent the spherical-collapse model can help in understanding these differences, in both real and redshift space. I discuss how this is difficult to do if one attempts to identify haloes directly, because in that case one is subject to the vagaries of halofinding algorithms. However, I demonstrate that the halo model of structure formation provides an accurate non-linear response in the power spectrum, but only if results from spherical collapse that include formation hysteresis are properly incorporated. I comment on how this fact can be used to provide per cent level accurate matter power-spectrum predictions for dark energy models for k ≤ 5 h Mpc-1 by using the halo model as a correction to accurate ΔCDM simulations. In the Appendix, I provide some fitting functions for the linear-collapse threshold (δc) and virialized overdensity (Δv) that are valid for a wide range of dark energy models. I also make my spherical-collapse code available at https://github.com/alexander-mead/collapse. [ABSTRACT FROM AUTHOR]

The main topic of this article comprises four unpublished Arabic texts on astrolabelike instruments for showing the conditions of eclipses. They are the earliest technical descriptions of eclipse computers in any language. The first text is a treatise by ʿAlī ibn ʿĪsā (ninth century) on a special astrolabe for lunar phases and eclipses. The second text is an anonymous redaction of the first text with some omissions and additions. The third text describes a similar instrument with a different design, which was invented by Muḥammad ibn Muḥammad Nasṭūlus al-Asṭurlābī in the year 893/894 CE. The fourth anonymous text describes a plate for a graphical solution of the size of a lunar eclipse. In the concluding part, later Arabic descriptions of eclipse computers are summarized, some traces of these texts on real astrolabes are mentioned, and finally some comparable medieval Latin texts are referred to. Four Appendices contain an edition of the Arabic texts and English translations. [ABSTRACT FROM AUTHOR]

In cosmological N-body simulations, the representation of dark matter as discrete 'macroparticles' suppresses the growth of structure, such that simulations no longer reproduce linear theory on small scales near kNyquist. Marcos et al. demonstrate that this is due to sparse sampling of modes near kNyquist and that the often-assumed continuum growing modes are not proper growing modes of the particle system. We develop initial conditions (ICs) that respect the particle linear theory growing modes and then rescale the mode amplitudes to account for growth suppression. These ICs also allow us to take advantage of our very accurate N-body code ABACUS to implement second-order Lagrangian perturbation theory (2LPT) in configuration space. The combination of 2LPT and rescaling improves the accuracy of the late-time power spectra, halo mass functions, and halo clustering. In particular, we achieve 1 per cent accuracy in the power spectrum down to kNyquist, versus kNyquist/4 without rescaling or kNyquist/13 without 2LPT, relative to an oversampled reference simulation.We anticipate that our 2LPT will be useful for large simulations where fast Fourier transforms are expensive and that rescaling will be useful for suites of medium-resolution simulations used in cosmic emulators and galaxy survey mock catalogues. Code to generate ICs is available at https://github.com/lgarrison/zeldovich-PLT. [ABSTRACT FROM AUTHOR]

Research-based science education (RBSE) is an instructional model that integrates scientific research with education by giving introductory-level undergraduate astronomy students an opportunity to do authentic research with real data. Its goals are threefold: (1) to teach that science is a process of discovery, not just a body of knowledge, (2) to improve attitudes towards science and STEM careers, and (3) to develop critical thinking, teamwork, and goal-driven work skills that are important in any career path. The RBSE curriculum currently consists of five authentic research projects in astronomy. Each project uses real astronomical data from professional observatories to investigate authentic research questions for which the answers are not known. In other words, in order to learn science, students are given the opportunity to actually do science. The results of RBSE student research have been submitted to scientific databases, presented at professional conferences, and published in refereed journals. In this paper we introduce the RBSE instructional model. To serve as an example, we also describe one of the RBSE research projects wherein students are searching for classical novae in the Andromeda Galaxy (M31). We encourage instructors interested in incorporating the RBSE curriculum into their teaching to learn more at the RBSE websites. [ABSTRACT FROM AUTHOR]

We introduce a new algorithm for colour separation and deblending of multi-band astronomical images called MuSCADeT which is based on Morpho-spectral Component Analysis of multi-band images. The MuSCADeT algorithm takes advantage of the sparsity of astronomical objects in morphological dictionaries such as wavelets and their differences in spectral energy distribution (SED) across multi-band observations. This allows us to devise a model independent and automated approach to separate objects with different colours. We show with simulations that we are able to separate highly blended objects and that our algorithm is robust against SED variations of objects across the field of view. To confront our algorithm with real data, we use HST images of the strong lensing galaxy cluster MACS J1149+2223 and we show that MuSCADeT performs better than traditional profile-fitting techniques in deblending the foreground lensing galaxies from background lensed galaxies. Although the main driver for our work is the deblending of strong gravitational lenses, our method is fit to be used for any purpose related to deblending of objects in astronomical images. An example of such an application is the separation of the red and blue stellar populations of a spiral galaxy in the galaxy cluster Abell 2744. We provide a python package along with all simulations and routines used in this paper to contribute to reproducible research efforts. [ABSTRACT FROM AUTHOR]

Hydrogen induced cold cracking (HICC) and hydrogen embrittlement (HE) are influenced by the microstructural evolution, residual plastic strain (i.e. local misorientation), recrystallization of grains and the resultant grain boundary characteristic distribution (GBCD) brought about by welding processes. HICC and HE are known to cause failures in aerospace components and it is vitally important to quantify the microstructural evolution, degree of residual plastic strain and determine the GBCD across dissimilar weld joints in order to assess the susceptibility of the weld joint to these phenomena. In this investigation a full a microstructural characterization study was carried out at various locations within and around a dissimilar weld joint of pulse-plated nickel (PP-Ni) and Inconel 718 (IN718), taken from an aerospace component. Areas examined included the base metals, weld fusion zone and heat affected zones on both sides of the weld joint, formed via electron beam welding. Scanning electron microscopy (SEM) in combination with electron backscatter diffraction (EBSD) was employed to measure the residual plastic strain, grain structure, grain size distribution, crystal orientation distribution, grain boundary misorientation distribution and GBCD of the dissimilar metal weld joint. Finally a metallurgical examination was carried out using SEM on the IN718 HAZ in order to investigate the secondary phase precipitation arising from the welding process. The results shows large variety of GBCD, crystallographic orientation distribution, local plastic strain distribution and grain size, shape and structure distribution across dissimilar weld joint. And these localized microstructural characterized data sets need to be carefully transferred using data-driven approach in order to develop predictive multiscale material modelling for hydrogen induced cracking and hydrogen embrittlement. [ABSTRACT FROM AUTHOR]

Current and future surveys of large-scale cosmic structure are associated with a massive and complex datastream to study, characterize, and ultimately understand the physics behind the two major components of the ‘Dark Universe’, dark energy and dark matter. In addition, the surveys also probe primordial perturbations and carry out fundamental measurements, such as determining the sum of neutrino masses. Large-scale simulations of structure formation in the Universe play a critical role in the interpretation of the data and extraction of the physics of interest. Just as survey instruments continue to grow in size and complexity, so do the supercomputers that enable these simulations. Here we report on HACC (Hardware/Hybrid Accelerated Cosmology Code), a recently developed and evolving cosmology N-body code framework, designed to run efficiently on diverse computing architectures and to scale to millions of cores and beyond. HACC can run on all current supercomputer architectures and supports a variety of programming models and algorithms. It has been demonstrated at scale on Cell- and GPU-accelerated systems, standard multi-core node clusters, and Blue Gene systems. HACC’s design allows for ease of portability, and at the same time, high levels of sustained performance on the fastest supercomputers available. We present a description of the design philosophy of HACC, the underlying algorithms and code structure, and outline implementation details for several specific architectures. We show selected accuracy and performance results from some of the largest high resolution cosmological simulations so far performed, including benchmarks evolving more than 3.6 trillion particles. [ABSTRACT FROM AUTHOR]

We present a new symplectic integrator designed for collisional gravitational N-body problems which makes use of Kepler solvers. The integrator is also reversible and conserves nine integrals of motion of the N-body problem to machine precision. The integrator is second order, but the order can easily be increased by the method of Yoshida. We use fixed time step in all tests studied in this paper to ensure preservation of symplecticity. We study small N collisional problems and perform comparisons with typically used integrators. In particular, we find comparable or better performance when compared to the fourth-order Hermite method and much better performance than adaptive time step symplectic integrators introduced previously. We find better performance compared to SAKURA, a non-symplectic, non-time-reversible integrator based on a different two-body decomposition of the N-body problem. The integrator is a promising tool in collisional gravitational dynamics. [ABSTRACT FROM AUTHOR]

We investigate the weak lensing effect by line-of-sight structures with a surface mass density of ≲ 108 M⊙ arcsec-2 in QSO-galaxy quadruple lens systems. Using high-resolution N-body simulations in warm dark matter (WDM) models and observed four quadruple lenses that show anomalies in the flux ratios, we obtain constraints on the mass of thermal WDM, mWDM ≥ 1.3 keV (95 per cent CL) assuming that the density of the primary lens is described by a singular isothermal ellipsoid (SIE). The obtained constraint is consistent with those from Lyman α forests and the number counts of high-redshift galaxies at z > 4. Our results show that WDM with a free-streaming comoving wavenumber kfs ≤ 27 h Mpc-1 is disfavoured as the major component of cosmological density at redshifts 0.5 ≲ z ≲ 4 provided that the SIE models describe the gravitational potentials of the primary lenses correctly. [ABSTRACT FROM AUTHOR]

Simulations of the entire universe are by definition models of the largest and most complex physical system that exists. In carrying them out, simulators seek to discretize the matter (and radiation) in a model universe and follow their evolution from the Big Bang to the present day. [ABSTRACT FROM AUTHOR]

The availability of large-scale digital surveys offers tremendous opportunities for advancing scientific knowledge in the astrophysics community. Nevertheless, the analysis of these data often requires very powerful computational resources. Science gateway technologies offer Web-based environments to run applications with little concern for learning and managing the underlying infrastructures that execute them. This paper focuses on the issues related to the development of a science gateway customized for the needs of the astrophysics community. The VisIVO Science Gateway is wrapped around a WS-PGRADE/grid User Support Environment portal integrating services for processing and visualizing large-scale multidimensional astrophysical data sets on distributed computing infrastructures. We discuss the core tools and services supported including an application for mobile access to the gateway. We report our experiences in supporting specialized astrophysical communities requiring development of complex workflows for visualization and numerical simulations. Further, available platforms are discussed for sharing workflows in collaborative environments. Finally, we outline our vision for creating a federation of science gateways to benefit astrophysical communities by sharing a set of services for authentication, computing infrastructure access and data/workflow repositories. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article discusses supercomputers and antenna arrays in Northern Europe, South Africa, and Australia that are being used to detect the epoch of reionization (EoR) signal, which is period during which the gas in the Universe went from being neutral to a state in which it became ionized. Australia's Murchison Widefield Array (MWA), the Netherlands Institute for Radio Astronomy's (ASTRON's) Low Frequency Array (LOFAR), and the interference of extragalactic foreground noise are discussed.

Starting in the 1960s, astronomers' analog view of the universe gradually transformed as scientists and engineers introduced digital computers, electronic detectors, and magnetic recording media into observatory domes and laboratories. The advantages of this were considerable: once the underlying technical architecture and social practices were in place, digital data can be more easily analyzed, manipulated, transported, and communicated. As they replaced and supplemented older technologies, astronomers' basic research practices changed accordingly. This helped reshape norms and behaviors in the research community, altering astronomy' s moral economy. The importance of collecting, processing, and sharing digital data transcended specific institutions, individual research questions, and national boundaries. This article explores this process, using representative examples and the metaphor of data friction, focusing on both the development of hardware and data standards. For astronomers, the transition from analog to digital was, in both senses of the phrase, a universal concern. [ABSTRACT FROM AUTHOR]

Dramatic increases in the amount and complexity of stellar data must be matched by new or refined algorithms that can help scientists make sense of this data and so better understand the universe. ParaHeap-k is a parallel cluster algorithm for analyzing big data that can potentially prove useful to astronomical research. [ABSTRACT FROM PUBLISHER]

This article includes the following "mini-articles" about applications and examples of computing in astronomy: "Visualizing the Universe: Using Modern Graphics Cards to Understand the Physical World," by F. Alexander Bogert, Nicholas Smith, and John Holdener; "Visualizing Big Data in Astronomy: The Automated Movie Production Environment Distribution and Display (AMPED) Pipeline," by Eric M. De Jong; "Supporting Distributed, Collaborative Review and Classification of Fast Transient Events," by Andrew F. Hart, Luca Cinquini, Shakeh E. Khudikyan, David R. Thompson, Chris A. Mattmann, Kiri Wagstaff, Joseph Lazio, and Dayton L. Jones; "Big Data Technologies at JPL," by Dayton L. Jones; and "The Astrophysics Source Code Library: ascl.net," by Alice Allen, Lior Shamir, and Peter Teuben. [ABSTRACT FROM PUBLISHER]

Pydron, a system that bridges the gap between interactive data analysis and scalable computing, enables astronomers to process large datasets with Python without the complexities of managing parallel processing code. [ABSTRACT FROM PUBLISHER]

For next-generation radio telescopes such as the Square Kilometre Array, seemingly minor changes in scientific constraints can easily push computing requirements into the exascale domain. The authors propose a model for engineers and astronomers to understand these relations and make tradeoffs in future instrument designs. [ABSTRACT FROM PUBLISHER]

Aims. We present an image reconstruction method for optical/infrared long-baseline interferometry called IRBis (image reconstruction software using the bispectrum). We describe the theory and present applications to computer-simulated interferograms. Methods. The IRBis method can reconstruct an image from measured visibilities and closure phases. The applied optimization routine ASA_CG is based on conjugate gradients. The method allows the user to implement different regularizers, apply residual ratios as an additional metric for goodness-of-fit, and use previous iteration results as a prior to force convergence. Results. We present the theory of the IRBis method and several applications of the method to computer-simulated interferograms. The image reconstruction results show the dependence of the reconstructed image on the noise in the interferograms (e.g., for ten electron read-out noise and 139 to 1219 detected photons per interferogram), the regularization method, the angular resolution, and the reconstruction parameters applied. Furthermore, we present the IRBis reconstructions submitted to the interferometric imaging beauty contest 2012 initiated by the IAU Working Group on Optical/IR Interferometry and describe the performed data processing steps. [ABSTRACT FROM AUTHOR]

Abstract: While software and algorithms have become increasingly important in astronomy, the majority of authors who publish computational astronomy research do not share the source code they develop, making it difficult to replicate and reuse the work. In this paper we discuss the importance of sharing scientific source code with the entire astrophysics community, and propose that journals require authors to make their code publicly available when a paper is published. That is, we suggest that a paper that involves a computer program not be accepted for publication unless the source code becomes publicly available. The adoption of such a policy by editors, editorial boards, and reviewers will improve the ability to replicate scientific results, and will also make computational astronomy methods more available to other researchers who wish to apply them to their data. [Copyright &y& Elsevier]

Abstract: We introduce Astronomy and Computing, a new journal for the growing population of people working in the domain where astronomy overlaps with computer science and information technology. The journal aims to provide a new communication channel within that community, which is not well served by current journals, and to help secure recognition of its true importance within modern astronomy. In this inaugural editorial, we describe the rationale for creating the journal, outline its scope and ambitions, and seek input from the community in defining in detail how the journal should work towards its high-level goals. [Copyright &y& Elsevier]

Abstract: Although the roles of data centers and computing centers are becoming more and more important, and on-line research is becoming the mainstream for astronomy, individual research based on locally hosted data is still very common. With the increase of personal storage capacity, it is easy to find hundreds to thousands of FITS files in the personal computer of an astrophysicist. Because Flexible Image Transport System (FITS) is a professional data format initiated by astronomers and used mainly in the small community, data management toolkits for FITS files are very few. Astronomers need a powerful tool to help them manage their local astronomical data. Although Virtual Observatory (VO) is a network oriented astronomical research environment, its applications and related technologies provide useful solutions to enhance the management and utilization of astronomical data hosted in an astronomer’s personal computer. FITSManager is such a tool to provide astronomers an efficient management and utilization of their local data, bringing VO to astronomers in a seamless and transparent way. FITSManager provides fruitful functions for FITS file management, like thumbnail, preview, type dependent icons, header keyword indexing and search, collaborated working with other tools and on-line services, and so on. The development of the FITSManager is an effort to fill the gap between management and analysis of astronomical data. [Copyright &y& Elsevier]

BSTRACT [ABSTRACT FROM AUTHOR]

sample of 230 galaxies has been compiled based on their IRAS FSC fluxes to study their multiwavelength properties and carry out comparative analyses with other similar samples. To understand the nature of these galaxies, a comparison with a sample of bright ULIRGs having fluxes at 60 μm fν > 1 Jy and 14 optically faint IRAS FSC galaxies is presented. This comparison shows that galaxies found by IRAS are not always strong infrared sources and that the objects from the sample of ULIRGs represent a sample of extreme galaxies, which are very powerful infrared sources. We have confirmed the consistency between Star Formation Rates (SFRs) calibrated based on luminosities of the PAH feature at 7.7 μm and radio 1.4 GHz flux densities. We have estimated the extinction for our 230 objects using SFRs calibrated from the PAH feature compared to ultraviolet flux, which shows that only 1% of the ultraviolet continuum typically escapes extinction by dust within a starburst. [ABSTRACT FROM AUTHOR]

search for Hα objects in four fields with an overall area of about 0.14 square degrees in the region of NGC 6910 (the core of the known Cyg OB9 association) has led to the discovery of 64 emission stars, of which 49 are newly detected. The high surface density is indicative of a very rich T association or, possibly, of the projection of several T associations onto one another in this direction. The latter possibility is also indicated by the range of the R photometric stellar magnitudes of the emission stars, 9.68-19.42. A comparison with earlier observations shows that for many of the stars, the emission line intensity is variable. A P Cyg Hα line profile is recorded for the star V 1515 Cyg with an emission component equivalent width that greatly exceeds the equivalent absorption width. [ABSTRACT FROM AUTHOR]

database for the entire catalog of the Second Byurakan Survey (SBS) galaxies is presented. It contains new measurements of their optical parameters and additional information taken from the literature and other databases. The measurements were made using I (near-infrared), F (red), and J (blue) band images from photographic sky survey plates obtained by the Palomar Schmidt telescope and extracted from the STScI Digital Sky Survey (DSS). The database provides accurate coordinates, morphological type, spectral and activity classes, apparent magnitudes and diameters, axial ratios and position angles, as well as number counts of neighboring objects in a circle of radius 50 kpc. The total number of individual SBS objects in the database is now 1676. The 188 Markarian galaxies that were re-discovered by SBS are not included in this database. We also include redshifts that are now available for 1576 SBS objects, as well as 2MASS infrared magnitudes for 1117 SBS galaxies. [ABSTRACT FROM AUTHOR]

The Virtual Observatory (VO) is an international project to collect astronomical data (images, spectra, simulations, mission-logs, etc.), organise them and develop tools that let astronomers access this huge amount of information. The VO not only simplifies the work of professional astronomers, it is also a valuable tool for education and public outreach. For teachers and astronomers who actively promote astronomy to the public, the VO is a great opportunity to access and use real astronomical data, and have a taste of the daily life of astronomers. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes two new 3D curvelet decompositions, which are built in a way similar to the first generation of curvelets (Starck et al., 2002 ). The first one, called BeamCurvelet transform, is well designed for representing 1D filaments in a 3D space, while the second one, the RidCurvelet transform, is designed to analyze 2D surfaces. We show that these constructions can be useful for different applications such as filament detection, denoising or inpainting. Hence, they could lead to alternative approaches for analyzing 3D cosmological data sets, such as catalogs of galaxies, λCDM simulation or weak lensing data. [Copyright &y& Elsevier]

Abstract: Diverse phyllosilicate deposits discovered previously in the Nili Fossae region with near infrared reflectance data are a window into the complex history of aqueous alteration on Mars. In this work, we used thermal infrared data from the Thermal Emission Spectrometer (TES) in combination with near infrared data from the Observatoire pour la Minéralogie, l’Eau, les Glaces, et l’Activité (OMEGA) to better constrain the mineralogy and geologic origin of these deposits. We developed a TES spectral index for identification of clay minerals, which correctly identifies the phyllosilicates in the Nili Fossae area and points to several other interesting deposits in the Syrtis Major region. However, detailed inspection of the TES spectral features of Nili Fossae phyllosilicates shows a feature at low wavenumbers (350–550cm−1) that is not an exact match to any specific Fe3+-, Al-, or Mg-rich phyllosilicate phase. Instead, the feature is more similar to basaltic glass and may indicate that the phyllosilicates in this region are: (1) rich in Fe2+ (based on similarity to trends seen in laboratory data of clay minerals), (2) poorly crystalline/extremely disordered, and/or (3) present within a matrix of actual basalt glass. This feature is similar to spectral features seen in altered rocks in the Columbia Hills region of Gusev Crater by previous authors. By calibrating measured spectral index values against mathematical spectral mixtures of typical martian dark surfaces and known abundances of alteration minerals, we are able to estimate an enrichment in abundance of alteration minerals in the altered surfaces. Many dark, Noachian deposits in the Nili Fossae area are enriched phyllosilicates by 20–30% (±10–15%) relative to dark, volcanic surfaces in the same region. The distribution and abundance of these phases indicates that alteration in the region was pervasive, but did not completely erase the original mineralogy of what was likely an Fe-rich basalt protolith. As a group, the Nili Fossae phyllosilicate deposits are fundamentally different from those found in the Mawrth Vallis region. Nili Fossae deposits have strong thermal infrared features related to admixed pyroxene, plagioclase, and occasionally olivine, whereas the Mawrth Vallis deposits contain no mafic minerals. Comparison of TES and OMEGA data also illustrates some more general differences between the datasets, including the impact of physical character of the martian surface on detectability of minerals in each spectral range. [Copyright &y& Elsevier]

Abstract: Feature-based hot spots are localized regions where the attributes of objects attain high values. There is considerable interest in automatic identification of feature-based hot spots. This paper approaches the problem of finding feature-based hot spots from a data mining perspective, and describes a method that relies on supervised clustering to produce a list of hot spot regions. Supervised clustering uses a fitness function rewarding isolation of the hot spots to optimally subdivide the dataset. The clusters in the optimal division are ranked using the interestingness of clusters that encapsulate their utility for being hot spots. Hot spots are associated with the top ranked clusters. The effectiveness of supervised clustering as a hot spot identification method is evaluated for four conceptually different clustering algorithms using a dataset describing the spatial distribution of ground ice on Mars. Clustering solutions are visualized by specially developed raster approximations. Further assessment of the ability of different algorithms to yield hot spots is performed using raster approximations. Density-based clustering algorithm is found to be the most effective for hot spot identification. The results of the hot spot discovery by supervised clustering are comparable to those obtained using the statistic, but the new method offers a high degree of automation, making it an ideal tool for mining large datasets for the existence of potential hot spots. [Copyright &y& Elsevier]

Abstract: The 395 late-type spiral galaxies brighter than 15m in r-band are selected from the Data Release 2 of Sloan Digital Sky Survey and the colormagnitude relations of these galaxies and their disks are investigated. It is found that the colors g − r, r − z and g − z of these galaxies and their disks are strongly correlated with the r-band absolute magnitudes, i.e., the more luminous galaxies (or disks) have the redder colors than the less luminous galaxies (or disks). And the correlation of galaxies is stronger than that of their disks. [Copyright &y& Elsevier]

Abstract: Using the All-Sky Monitor (ASM, 1.5–12–kev) data of Rossi X-ray Timing Explorer (RXTE) from January 1996 to May 2005, we have made a detailed analysis of the correlation between photon-count rate and spectral hardness ratio HR2 (5–12keV/3–5keV) of the black-hole candidate X-ray binary Cyg X-1 in 3 energy bands, namely the A-band (1.5–3keV), B-band (3–5keV) and Cband (5–12keV). By the study on the ASM data of 1-day time scale, we find: (1) When Cyg X-1 is in the soft state, the A-band photon-count rate and hardness ratio HR2 exhibit an anticorrelation, but in B-band and C-band there appears the positive correlation. When Cyg X-1 is in hard state, the photon-count rates in the A,B,C bands are all inversely correlated with the hardness ratio HR2; (2) No matter whether Cyg X-1 is in the soft state or the hard state, the hardness ratios HR2 and HR1 are always positively correlated. In addition, we have analyzed the “dwell by dwell” data of the ASM, and obtained the following interesting results: (1) In the period of MJD=52600–52760 (while Cyg X-1 is in the hard state), the photon-count rates in the A-band and B-band are inversely correlated with HR2, but in the C-band there appears a relatively strong positive correlation; (2) During the hard state, a clear anticorrelation exists between the hardness ratios HR2 and HR1. [Copyright &y& Elsevier]

We present a parallel implementation of an algorithm for calculating the two-point angular correlation function as applied in the field of computational cosmology. The algorithm has been specifically developed for a reconfigurable computer. Our implementation utilizes a microprocessor and two reconfigurable processors on a dual-MAP SRC-6 system. The two reconfigurable processors are used as two application-specific co-processors. Two independent computational kernels are simultaneously executed on the reconfigurable processors while data pre-fetching from disk and initial data pre-processing are executed on the microprocessor. The overall end-to-end algorithm execution speedup achieved by this implementation is over 90× as compared to a sequential implementation of the algorithm executed on a single 2.8 GHz Intel Xeon microprocessor. [ABSTRACT FROM AUTHOR]

Based on Open Grid Services Architecture (OGSA), the concept and the formal model of Pipeline Virtual Service (PVS) are proposed and presented in this paper. PVS is used to model a special type of grid workflow composed of a group of services that can be executed as a pipeline. A PVS Pre-Scheduling Pattern is described in detail, which can overlap the execution time of a PVS with the time of generating and optimizing the scheduling solution pool. The Pattern includes two independent components, the solution generating component (GenFunc) and the solution execution component (ExeFunc). GenFunc can take advantage of the powerful computing potential of grid environment to find the optimal or a near optimal scheduling solution, while ExeFunc can select a suitable scheduling solution and put a PVS into running as soon as possible. Two corresponding algorithms, SODGen and SODExe, are also developed. The analytic and simulation results show that the PVS Pre-Scheduling Pattern can not only balance the scheduling cost and scheduling precision, save the scheduling time greatly, but also reduce the execution time through selecting the optimized solution. A prototype is designed and implemented for a large scale astronomy data processing center. The early engineering evaluation experiments show that the PVS Pre-Scheduling Pattern is feasible, efficient, and flexible in real astronomy data processing. [ABSTRACT FROM AUTHOR]