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Euchner, F., Pollmer, A., Gänsicke, B. T., Kube, J., & Beuermann, K. 2003, in ASP Conf. Ser., Vol. 314 Astronomical Data
Analysis Software and Systems XIII, eds. F. Ochsenbein, M. Allen, & D. Egret (San Francisco: ASP), 578
AstroCat/CVcat: A catalogue on Cataclysmic Variables based on a new framework for online interactive astronomical databases
Fabian Euchner, Alexander Pollmer, Klaus Beuermann
Universitäts-Sternwarte, Geismarlandstr. 11, D-37083 Göttingen, Germany
Boris T. Gänsicke
Department of Physics, University of Warwick, Coventry CV4 7AL, UK
Jens Kube
Stiftung Alfred-Wegener-Institut für Polar- und Meeresforschung in der Helmholtz-Gemeinschaft, Koldewey-Station,
N-9173 Ny-Ålesund, Norway
Abstract:
We report on the progress of the development of CVcat, an interactive
catalogue on Cataclysmic Variables, which is the first application based on
AstroCat, a general framework for the installation and maintenance of
web-based interactive astronomical databases.
Registered users can contribute
directly to the catalogue content by adding new objects, object properties,
literature references, and annotations.
The scientific quality control of the
catalogue is carried out by a distributed editorial team.
Searches in CVcat can be performed by object name, classification,
certain properties or property ranges, and coordinates. Search results
can be retrieved in several output formats, including XML.
Old database states can be restored in order to ensure the citability
of the catalogue.
Furthermore, CVcat is designed to serve as a repository for
reduced data from publications.
Future prospects include the integration of AstroCat-based catalogues
in the international network of Virtual Observatories.
Traditionally, in astronomy the availability of online digital information is excellent with respect
to scientific publications (NASA's Astrophysics Data System, arXiv.org preprint
server) and raw observational data. With the development of the AstroCat software
we intend to fill the gap between these two categories by enabling astronomers to set up
interactive astronomical catalogues for reduced and inferred data (Fig. 1).
Figure 1:
Level of abstraction and digital availability of astronomical information.
 |
AstroCat is a software framework for the implementation of a new type of web-based
interactive astronomical catalogues.
AstroCat-based catalogues are intended to hold information on the physical properties
of astronomical objects of a specific class. We provide the possibility to account for
fine-grained hierarchical sub-classifications of the selected objects. The information contained
in the catalogue should be gathered from trustworthy publications, preferably from refereed papers.
The scientific quality control is performed by users who assumed editorial duties. If available,
a hyperlink to an electronic version of the referenced publication should be given for each catalogue
entry (e.g. via the ADS, the astro-ph preprint server, or online journals like the
Information Bulletin on Variable Stars).
We will also provide the possibility for authors to share reduced data (spectra, light curves, images, etc.) from
their publications with the community of users.
Our new concept of astronomical catalogues and the differences to existing catalogues
are best characterized by the terms interactivity, up-to-dateness
and accessibility:
Interactivity: All registered users may contribute to the database content by adding new data.
The reliability of the data is ensured by an editorial team which is allowed to modify catalogue
entries. We achieve a high level of objectiveness by allowing for several entries per property.
We also allow for detailed annotations on the catalogue entries.
Up-to-dateness: Most `classical' catalogues are updated only in irregular and/or lengthy intervals.
In AstroCat-based catalogues all changes to the database are made instantly visible to the users.
To ensure the citability of the catalogue, we provide a mechanism for restoring previous states of
the catalogue content.
Accessibility: The web-based character allows for simple but powerful searching on the
database via a web browser. The query results can be formatted in various user-definable styles.
We also provide the possibility to retrieve the query results in XML format in order to supply the user
with semantically enriched data.
Additional information on the AstroCat/CVcat project can be found at our
web page.
At this location, we provide an online
discussion forum
where comments on the project can be placed.
CVcat, a first version of an online catalogue on Cataclysmic Variables (CVs),
was developed by the CV group in Göttingen and presented to the public in August 2001
due to the increasing need in the community of CV researchers for an authoritative, up-to-date,
online database of the relevant objects (Kube et al. 2003). In this catalogue some of the concepts
of AstroCat are already realized. It comprises data from `classical'
catalogues on CVs (mainly Ritter & Kolb 2003) as well as additional information compiled
manually from numerous publications.
Since the acceptance of CVcat in the CV community is good, we decided to
re-implement the catalogue with additional features providing more flexibility and convenience
to the users. For that purpose, we started to develop the AstroCat framework which is not
only designed for the re-implementation of CVcat, but can also be used for the
installation of catalogues covering different astronomical fields.
Up to now, CVcat is used by 
150 registered users and can be accessed at
http://www.cvcat.org. The upgrade to the AstroCat-based version is
planned for January 2004. A non-interactive demonstration of the new version can already be
found at http://astrocat.uni-goettingen.de/cvcat-demo/.
AstroCat is especially suited to set up databases used by relatively small research communities
(several hundred users). Since all catalogue entries should be approved by editors, we estimate
the maximum number of objects that can be handled properly to be several thousands. The possibility to
comment on catalogue entries is particularly useful if extensive calculations and/or non-standard
methods are required to derive the respective object properties.
The catalogue data is held in a PostgreSQL database management system.
The communication between the database and the webserver (Apache) is controlled by PHP scripts.
Queries to and results from the database are handled internally in an XML dialect,
AstroCatML,
for which an XML Schema can be found on our web page.
A schematic view of the data flow in AstroCat can be found in Fig. 2.
Figure 2:
Software components and data flow in AstroCat.
 |
After the completion of CVcat we plan to transfer the new concept to a different field of
astronomical research by installing a catalogue on extrasolar planets (EPcat) based on
the AstroCat software.
Furthermore, we will provide a registry where the metadata of all AstroCat-based catalogues
can be stored, in order to establish interoperability mechanisms between catalogues, e.g. simultaneous searches.
It is also intended to integrate the information provided by the catalogues based on AstroCat
in the global network of Virtual Observatories.
AstroCat/CVcat is funded by the Deutsche Forschungsgemeinschaft
(project number LIS 4 - 554 95 (1) SUB Göttingen).
The project is realized in collaboration with the Niedersächsische Staats- und Universitätsbibliothek (SUB),
Göttingen, in the framework of Virtuelle Fachbibliothek Astronomie.
CVcat will be hosted at the SUB after completion.
References
Kube, J., Gänsicke, B. T., Euchner, F. & Hoffmann, B.
2003, A&A, 404, 1159
Ritter, H. & Kolb. U. 2003, A&A, 404, 301
© Copyright 2004 Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, California 94112, USA
Next: Access to Databases of Atomic and Molecular Data in the VO
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