No Arabic abstract
We present the first attempts to build a user-friendly interface for the Virtual Observatory of the University of Guanajuato. The data tables will be accessible to the public through PHP scripts and SQL database managers, such as MySQL and PostgreSQL, all administrated through phpMyAdmin and pgMyAdmin. Although it is not made public yet, this interface will be the basis upon which the final front end for our VO will be built. Furthermore, we present a preliminary version of a web front end to the publicly available stellar population synthesis code STARLIGHT (starlight.ufsc.br) which will be made available with our VO. This front end aims to provide an easy and flexible access to the code itself, letting users fit their own observed spectra with their preferred combination of physical and technical parameters, rather than making available only the results of fitting a specific sample of spectra with predefined parameters.
The Virtual Observatory is a new technology of the astronomical research allowing the seamless processing and analysis of a heterogeneous data obtained from a number of distributed data archives. It may also provide astronomical community with powerful computational and data processing on-line services replacing the custom scientific code run on users computers. Despite its benefits the VO technology has been still little exploited in stellar spectroscopy. As an example of possible evolution in this field we present an experimental web-based service for disentangling of spectra based on code KOREL. This code developed by P. Hadrava enables Fourier disentangling and line-strength photometry, i.e. simultaneous decomposition of spectra of multiple stars and solving for orbital parameters, line-profile variability or other physical parameters of observed objects. We discuss the benefits of the service-oriented approach from the point of view of both developers and users and give examples of possible user-friendly implementation of spectra disentangling methods as a standard tools of Virtual Observatory.
In the Virtual Observatory (VO), the Registry provides the mechanism with which users and applications discover and select resources -- typically, data and services -- that are relevant for a particular scientific problem. Even though the VO adopted technologies in particular from the bibliographic community where available, building the Registry system involved a major standardisation effort, involving about a dozen interdependent standard texts. This paper discusses the server-side aspects of the standards and their application, as regards the functional components (registries), the resource records in both format and content, the exchange of resource records between registries (harvesting), as well as the creation and management of the identifiers used in the system based on the notion of authorities. Registry record authors, registry operators or even advanced users thus receive a big picture serving as a guideline through the body of relevant standard texts. To complete this picture, we also mention common usage patterns and open issues as appropriate.
This paper describes the main characteristics of the Virtual Observatory as a research infrastructure in Astronomy, and identifies those fields in which it can be of help for the community of spectral stellar libraries.
Until recently, it has been possible only for nearby galaxies to study the scaling relations between central black hole and host galaxy in detail. Because of the small number densities at low redshift, (luminous) AGN are underrepresented in such detailed studies. The advent of adaptive optics (AO) at large telescopes helps overcoming this hurdle, allowing to reach small linear scales over a wide range in redshift. Finding AO-suitable targets, i.e., AGN having a nearby reference star, and carrying out an initial multiwavelength classification is an excellent use case for the Virtual Observatory. We present our Virtual-Observatory approach to select an AO-suitable catalog of X-ray-emitting AGN at redshifts 0.1<z<1.
The Virtual Observatory has reached sufficient maturity for its routine scientific exploitation by astronomers. To prove this statement, here I present a brief description of the complete VO-powered PhD thesis entitled Galactic and extragalactic research with modern surveys and the Virtual Observatory comprising 4 science cases covering various aspects of astrophysical research. These comprize: (1) homogeneous search and measurement of main physical parameters of Galactic open star clusters in huge multi-band photometric surveys; (2) study of optical-to-NIR galaxy colors using a large homogeneous dataset including spectroscopy and photometry from SDSS and UKIDSS; (3) study of faint low-mass X-ray binary population in modern observational archives; (4) search for optical counterparts of unidentified X-ray objects with large positional uncertainties in the Galactic Plane. All these projects make heavy use of the VO technologies and tools and would not be achievable without them. So refereed papers published in the frame of this thesis can undoubtedly be added to the growing list of VO-based research works.