Virtual Observatory Project Research Articles

Comparative analysis of the positional accuracy of CCD measurements of small bodies in the solar system software CoLiTec and Astrometrica

The CoLiTec software for the automated search for small celestial objects of the solar system on a series of CCD frames has been developed within the Ukrainian virtual observatory project. Four comets and more than a thousand asteroids were discovered using the software. It was also used to send approximately 700000 positional CCD measurements to the Minor Planet Center. In this paper, accuracy factors of positional CCD measurements using the CoLiTec software are analyzed according to data from the Minor Planet Center. The comparative analysis of these factors according to the results of the processing of the same frames using CoLiTec and Astrometrica software is also conducted. In the case of low signal to noise ratios, the standard deviation of positional CCD measurements using the Astrometrica software is 30–50% greater than that of the CoLiTec software.

COMPARISON OF ZERO ZONE CATALOGUES OF THE FON PROGRAM BASED ON THE KYIV AND KITAB OBSERVATIONS

The two new catalogues for the zero zone of the FON project were created after the processing of two different collections of digitized photographic plates. The photographic plates were received at the DAZ and DWA telescopes of the Kitab observatory of the Republic of Uzbekistan (KO UAS) and of the Main astronomical observatory in Kyiv (MAO NASU) in the number of 90 and 120 plates, respectively. The digitization of these photographic plates in the frame of the Ukrainian Virtual Observatory project was performed by means of the Epson Expression 10000XL scanner with the scanning resolution of 1200 dpi. The coordinates of stars and galaxies for the both catalogues are determined in the system of the Tycho2 catalogue. The stellar magnitudes of all objects are done in B-magnitudes of the photoelectric standard system. The difference between the calculated and the reference positions is equal σαδ = ±0.06–0.07". The internal accuracy of the both catalogues for all objects is σ αδ = ±0.20", σB = ±0.18m and σ αδ = ±0.27", σ B = ±0.17m, respectively. We present the comparison of these both catalogues with each other and with the Tycho2, UCAC4 as well as PPMX catalogues and discuss the results.

Data modeling for the virtual observatory

Abstract The data modeling effort has played a key role in the Virtual Observatory project, and contributed to the effort to build a common reference framework to describe the necessary information attached to astronomical data: the metadata. Such metadata describe the observing parameters and characterize and qualify the observed measurements. These pieces of information are produced and stored in project archives. Standardizing a homogeneous representation of metadata allows uniform discovery and use of the data in the Virtual Observatory infrastructure. This paper describes the context of data modeling in the VO architecture and shows how data models support requirements on the data access layer and for applications development. How the modeling process has been undertaken is explained with a short overview of the different data models. We also discuss in some detail the lessons learned in this modeling and standardization effort.

Feeding an astrophysical database via distributed computing resources: The case of BaSTI

Abstract Stellar evolution model databases, spanning a wide ranges of masses and initial chemical compositions, are nowadays a major tool to study Galactic and extragalactic stellar populations. The Bag of Stellar Tracks and Isochrones (BaSTI) database is a VO-compliant theoretical astrophysical catalogue that collects fundamental datasets involving stars formation and evolution. The creation of this database implies a large number of stellar evolutionary computations that are extremely demanding in term of computing power. Here we discuss the efforts devoted to create and update the database using Distributed Computing Infrastructures and a Science Gateway and its future developments within the framework of the Italian Virtual Observatory project.

BaSTI: An updated, advanced and VO-compliant database of stellar evolution predictions

Abstract Stellar evolution model databases, spanning a wide ranges of masses and initial chemical compositions, are nowadays a major tool to study Galactic and extragalactic stellar populations. We describe here the current status of the widely used BaSTI (A Bag of Stellar Tracks and Isochrones) database. We focus in particular on the efforts devoted to port BaSTI to a VO-compliant environment, the BaSTI Web portal that enables users to retrieve data tables and run a range of web tools to facilitate the theoretical analysis of observations, and planned future developments within the framework of the Italian Virtual Observatory project.

The international outer planets watch atmospheres node database of giant-planet images

The Atmospheres Node of the International Outer Planets Watch (IOPW, formerly known as International Jupiter Watch; Russell et al., 1990) intends to encourage and coordinate the imaging observations and study of the atmospheres of the Giant Planets. The main activity of the atmospheres node is to provide an interaction between the professional and amateur astronomical communities maintaining a large database of images of the giant planets (primarily Jupiter and Saturn but with increasing contributions of Uranus and Neptune too). The observational datasets of Jupiter and Saturn correspond to images obtained in the visible range (300 nm–1 μm), during the last decade, most of them performed by amateur observers. We here describe the organization and structure of the database as posted on the Internet and in particular the PVOL software (Planetary Virtual Observatory Laboratory) designed to manage the site in the spirit of the Virtual Observatory projects. We also describe with examples the important role of the amateur–professional collaboration in the study of the atmospheres of Jupiter and Saturn in an epoch of large telescopes and spacecraft observations of both planets.

Astronomical Research Using Virtual Observatories

The Virtual Observatory (VO) for Astronomy is a framework that empowers astronomical research by providing standard methods to find, access, and utilize astronomical data archives distributed around the world. VO projects in the world have been strenuously developing VO software tools and/or portal systems. Interoperability among VO projects has been achieved with the VO standard protocols defined by the International Virtual Observatory Alliance (IVOA). As a result, VO technologies are now used in obtaining astronomical research results from a huge amount of data. We describe typical examples of astronomical research enabled by the astronomical VO, and describe how the VO technologies are used in the research.

Ontology-supported scientific data frameworks: The Virtual Solar-Terrestrial Observatory experience

We have developed a semantic data framework that supports interdisciplinary virtual observatory projects across the fields of solar physics, space physics and solar-terrestrial physics. This work required a formal, machine understandable representation for concepts, relations and attributes of physical quantities in the domains of interest as well as their underlying data representations. To fulfill this need, we developed a set of solar-terrestrial ontologies as formal encodings of the knowledge in the Ontology Web Language–Description Logic (OWL–DL) format. We present our knowledge representation and reasoning needs motivated by the context of Virtual Observatories, from fields spanning upper atmospheric terrestrial physics to solar physics, whose intent is to provide access to observational datasets. The resulting data framework is built upon semantic web methodologies and technologies and provides virtual access to distributed and heterogeneous sets of data as if all resources appear to be organized, stored and retrieved from a local environment. Our conclusion is that the combination of use case-driven, small and modular ontology development, coupled with free and open-source software tools and languages provides sufficient expressiveness and capabilities for an initial production implementation and sets the stage for a more complete semantic-enablement of future frameworks.

BaSTI, a Bridge between Grid and Virtual Observatory Part 1: BaSTI inside the VO

ABSTRACTIn the first part of this work we describe a new relational database (DB) created for storing metadata of stellar evolution models for a large range of masses and initial chemical compositions, which allows searching for data by scientific quantities and useful parameters. These data users can access the DB and might select a good catalog of evolutionary tracks and/or isochrones for making scientific studies and comparison with observational data. We also present a new Web portal where users can download scientific data of interest. This work has been conduced within the Italian Theoretical Virtual Observatory (ITVO) project, which aims to register these theoretical data under the Virtual Observatory standard and provide a set of standard tools able to visualize and analyze observational and also theoretical data. In the second part of the work we describe the link between the Grid infrastructure and the Virtual Observatory services as delineated by G. Taffoni and colleagues in 2006 and by F. Pasian and colleagues in 2008.

The TVO Archive for Cosmological Simulations: Web Services and Architecture

ABSTRACTIn order to offer an intuitive but effective access to a growing number of cosmological simulations, we have developed the Italian Theoretical Virtual Observatory project (ITVO), as described by Pasian and colleagues in 2006. In this work we describe two Web portals as two ways to access and share complex data coming from numerical astrophysical simulations. We present a set of Web services aimed at offering services such as Simple Numeric Access (ProtocolSNAPSimple Numeric Access Protocol), as described by Gheller and colleagues in 2006, and Randomizers dealing with different data formats. The Web services technology allows us to run a particular task (a SNAP job, for instance) close to its data, avoiding an expensive data transfer.

SkyMouse: A smart interface for astronomical on-line resources and services

With the development of network and the World Wide Web (WWW), the Internet has been growing and changing dramatically. More and more on-line database systems and different kinds of services are available for astronomy research. How to help users find their way through the jungle of information services becomes an important challenge. Although astronomers have been aware of the importance of interoperability and introduced the concept of Virtual Observatory as a uniform environment for future astronomical on-line resources and services, transparent access to heterogeneous on-line information is still difficult. SkyMouse is a lightweight interface for distributed astronomical on-line resources and services, which is designed and developed by us, i.e., Chinese Virtual Observatory project. Taking advantage of screen word-capturing technology, different kinds of information systems can be queried through simple mouse actions, and results are returned in a uniform web page. SkyMouse is an easy to use application, aiming to show basic information or to create a comprehensive overview of a specific astronomical object. In this paper current status of on-line resources and services access is reviewed; system architecture, features and functions of SkyMouse are described; challenges for intelligent interface for on-line astronomical resources and services are discussed.

Study on the environment around QSOs with redshift of 1–3 using the JVO System

Virtual Observatory (VO) is an emerging astronomical infrastructure for sharing the astronomical data set in the world. National Astronomical Observatory of Japan (NAOJ) started its VO project (Japanese Virtual Observatory – JVO) in 2002, and developed JVO portal prototypes. We have carried out several science use cases, such as cosmic string searches and QSO environment studies, by using the prototype system to examine the functionality of the system. This paper describes a preliminary result of the latter science use case.

VOFilter: Bridging Virtual Observatory and Industrial Office Applications

VOFilter is an XML based filter developed by the Chinese Virtual Observatory project to transform tabular data files from VOTable format into OpenDocument format. VOTable is an XML format defined for the exchange of tabular data in the context of the Virtual Observatory (VO). It is the first Proposed Recommendation defined by International Virtual Observatory Alliance, and has obtained wide support from both the VO community and many Astronomy projects. OpenOffice.org is a mature, open source, and front office application suite with the advantage of native support of industrial standard OpenDocument XML file format. Using the VOFilter, VOTable files can be loaded in OpenOffice.org Calc, a spreadsheet application, and then displayed and analyzed as other spreadsheet files. Here, the VOFilter acts as a connector, bridging the coming VO with current industrial office applications. We introduce Virtual Observatory and technical background of the VOFilter. Its workflow, installation and usage are presented. Existing problems and limitations are also discussed together with the future development plans.

Future Directions in Astronomy Visualization

AbstractDespite the large budgets spent annually on astronomical research equipment such as telescopes, instruments, and supercomputers, the general trend is to analyze and view the resulting datasets using small, two-dimensional displays. We report here on alternative advanced image displays, with an emphasis on displays that we have constructed, including stereoscopic projection, multiple projector tiled displays, and a digital dome. These displays can provide astronomers with new ways of exploring the terabyte and petabyte datasets that are now regularly being produced from all-sky surveys, high-resolution computer simulations, and Virtual Observatory projects. We also present a summary of the Advanced Image Displays for Astronomy (AIDA) survey which we conducted from 2005 March–May, in order to raise some issues pertinent to the current and future level of use of advanced image displays.

Data standards for the international virtual observatory

A primary goal of the International Virtual Observatory Alliance, which brings together Virtual Observatory Projects from 16 national and international development projects, is to develop, evaluate, test, and agree upon standards for astronomical data formatting, data discovery, and data delivery. In the three years that the IVOA has been in existence, substantial progress has been made on standards for tabular data, imaging data, spectroscopic data, and large-scale databases and on managing the metadata that describe data collections and data access services. In this paper, I describe how the IVOA operates and give my views as to why such a broadly based international collaboration has been able to make such rapid progress.

The Virtual Observatories: a major new facility for astronomy: linking ELTs, great observatories and the science community

We describe how the Virtual Observatory (VO) projects in Europe, the USA, Japan, and elsewhere are meeting the challenge of providing simple and efficient access to the data from the world's observational facilities, together with applications and computational resources required to support the analysis of this data. We note the pan-European Euro-VO project and its technological development VO-TECH project which are now in the process of designing the framework for comprehensive access to emerging high data volume facilities such as ESO's VISTA infrared survey telescope.Science drivers from major new astronomical missions are helping to define the development of the VO. Scientifically this is in terms of developing systems able to meet the demands of the main science programmes shaping the ELTs. VOs must be able to handle the large data streams from the complex multiplexed instruments on the ELTs, and provide access to applications required to analyse/interpret the data. VOs must enable the effective distribution of ELT data to the global community.Conversely, the rapid development of the Virtual Observatory, offers opportunities for major new projects such at the ELTs. This could be: in the design of their down stream data-flow systems; in terms of opening up access to ‘real-time’ availability of ancillary data flows; in multi-wavelength observational programmes.We highlight these areas, and give some specific current examples of early VO usage in delivering science from, e.g. the mining of deep multi-wavelength surveys to study the high redshift universe.

USING VIRTUAL OBSERVATORY TOOLS FOR ASTRONOMICAL RESEARCH

Construction of the Virtual Observatory (VO) is a great concern to the astronomical community in the 21st century. We present an outline of the concept and necessity of the va and the current status of various VO projects including the 15 national ones and the International Virtual Observatory Alliance (IVOA). We summarize the possible science cases that could be solved by using the VO data/tools, real science cases which are the results of using current VO tools, and our own work of using AstroGrid, the United Kingdom national VO, for a research on star formation history of galaxies.

Neural neZtworks in astronomy

In the last decade, the use of neural networks (NN) and of other soft computing methods has begun to spread also in the astronomical community which, due to the required accuracy of the measurements, is usually reluctant to use automatic tools to perform even the most common tasks of data reduction and data mining. The federation of heterogeneous large astronomical databases which is foreseen in the framework of the astrophysical virtual observatory and national virtual observatory projects, is, however, posing unprecedented data mining and visualization problems which will find a rather natural and user friendly answer in artificial intelligence tools based on NNs, fuzzy sets or genetic algorithms. This review is aimed to both astronomers (who often have little knowledge of the methodological background) and computer scientists (who often know little about potentially interesting applications), and therefore will be structured as follows: after giving a short introduction to the subject, we shall summarize the methodological background and focus our attention on some of the most interesting fields of application, namely: object extraction and classification, time series analysis, noise identification, and data mining. Most of the original work described in the paper has been performed in the framework of the AstroNeural collaboration (Napoli-Salerno).

The Grid Grew from Physicists’ Computing Needs

Foster replies: I appreciated Maurice Jacob’s thoughtful comments on the important role that physics and physicists often play in advancing information technology. I believe strongly in the use of challenging practical problems as drivers for IT R&D; such problems serve to focus on the real issues and provide rapid, if sometimes painful, feedback when apparently good ideas do not work. I am also convinced that, to achieve the order-of-magnitude performance improvements promised by Grids, we must engage not only discipline specialists but also computer scientists: for better or worse, it is no longer sufficient to view IT issues as secondary to the physics. For these reasons, I and many of my colleagues are so excited about current Grid projects, many of which involve genuine multidisciplinary partnerships focused on extremely challenging problems.Jacob speaks more specifically to the important role that CERN has long played in IT. In a brief overview article, I could not discuss specific projects; with more space, I would have written at length about the plans and achievements of the CERN-led European Union Data Grid and DataTAG projects, the pioneering work at Italy’s National Institute for Nuclear Physics (INFN), and other physics-focused Grid initiatives. (A list of project URLs can be found at http://www.mcs.anl.gov/~foster/grid-projects.) I would also have discussed the various virtual observatory projects (see Physics Today 0031-9228 55 2 2002 20 https://doi.org/10.1063/1.1461322. February 2002, page 20 ), and environmental data Grid efforts. I hope that Jacob’s letter and my response will clarify that physics problems and physicists are indeed central to the emergence and evolution of Grid computing.We must all hope, as Jacob suggests, that physics will continue to have the opportunity to pose IT challenges of the magnitude associated with the LHC. © 2002 American Institute of Physics.