Next: AstroCat/CVcat: A catalogue on Cataclysmic Variables based on a new framework for online interactive astronomical databases
Up: Surveys, Archives & VO
Previous: XCAT-DB a Public Interface for the SSC XMM-Newton Catalogue
Table of Contents - Subject Index - Author Index - Search - PS reprint - PDF reprint

Salgado, J. 2003, in ASP Conf. Ser., Vol. 314 Astronomical Data Analysis Software and Systems XIII, eds. F. Ochsenbein, M. Allen, & D. Egret (San Francisco: ASP), 574

ESA ISO and XMM-Newton Archives Inter-Operability and VO services

Christophe Arviset, Pedro Osuna, Jesus Salgado
RSSD Archive Development Team, ESA VILSPA, PO BOX 50727, 28080 Madrid, Spain

Abstract:

The ISO Data Archive (IDA) and XMM-Newton Science Archive (XSA) are usually accessed through a dedicated and powerful Java user interface available from any browser. To allow the access to external applications and expert or normal users that need to retrieve data directly from the archive bypassing the Java User Interface, an integrated Archive Inter Operability system (AIO) has been developed for XSA and IDA. This paper describes the general inter-operability services that this system provides as well as the specific VO standards services like SIAP that are already supported.

1. Introduction

Within the ESA's Science Operations and Data System Division, the Archive Development Team in Villafranca, Spain is responsible of developing and maintaining ESA Scientific Archives. For the ISO Data Archive (IDA) and the XMM-Newton Science Archive (XSA), the standard way to access to these ESA archives is through a powerful Java User Interfaces.

To allow the access to external applications and expert or normal users that need to retrieve data directly from the archive bypassing the Java User Interface, an integrated Archive Inter Operability system (AIO) has been developed for XSA and IDA.

The general AIO services are:

Postcard Server (URL)
Product Server (URL)
Product Server (Socket)

Later on, we have adapted our AIO inter-operability services to comply to the new VO standards, in particular to SIAP (Simple Image Access Prototype).

VO SIAP compatible AIO services are:

Image Query
Image Retrieval

2. General AIO Services

The IDA and XSA Archive Inter-Operability (AIO) systems allow external applications or archives to access directly the ISO and XMM-Newton data products bypassing the standard User Interfaces which require interactions with a human being.

Full documentation about how to use these services can be found at:

ISO : http://pma.iso.vilspa.esa.es:8080/aio/doc
XMM-Newton : http://xsa.vilspa.esa.es:8080/aio/doc

2.1 Postcard Server (URL)

The Postcard Server is accessible via a URL for each observation that returns an HTML page containing a quick-look view of the data products for that observation together with links to relevant documentation and links to the products themselves (via the Product Server). Example of the Postcard Servers are given in Figure 1.

The Postcard Server is already used by various archives such as CDS, Aladin, IRSA, ADS, HEASARC.

**Figure 1:** ISO and XMM-Newton Postcard Servers.
$\begin{figure} \epsscale{0.6} \plotone{D3_1.eps} \end{figure}$

2.2 Product Server (URL)

The Product Server is accessible via a URL that returns an HTML page with the link to the FTP server where the requested data have been put. After a few seconds, the data products download via FTP is initiated. Alternatively, by setting an extra parameter, the data products can be downloaded directly without going to the FTP server. This is particularly interesting for applications like Aladin who wants to request the products for future display. Various parameters in the URL define the level of data products that is requested by the user.

In combination with the Postcard Server which gives a quick view of the available data, the Product Server allows the user to download the real scientific products for his own analysis.

2.3 Product Server (Socket)

The Product Server can also run in the Socket mode in order from any client or user to directly request ISO and XMM-Newton data products without going through a URL. This option is heavily used by instrument experts who want to automatically retrieve data products for automatic analysis.

Various parameters can be specified in the command line to define the level of data products that is requested by the user. It can return a single file or a conjunction of files in a tar format. The Product Server also allows an XML file as input in order to specify a more complex data products request.

An example of an AIO session in Socket Mode is given in Figure 2.

**Figure 2:** AIO run in Socket Mode
$\begin{figure} \epsscale{0.6} \plotone{D3_2.eps} \end{figure}$

3. VO Compatible Services

The ISO and XMM-Newton AIO systems have then been adapted to support the VO standard SIAP (Simple Image Access Protocol) which basically supports two modes, image query and image retrieval.

Details about the adaptation of the existing AIO system to the VO standards can be found in Osuna et al. (2004).

3.1 SIAP Image Query

The SIAP defines various types of searches like cone search, target search based on some already defined UCDs. The results of such search can be in HTML or TEXT for human visualization but also in VOTable (the standard VO format) for easier parsing and later use into a VO client (e.g. Aladin). These SIAP Image Queries re-use the existing search mechanisms already present in the ISO Data Archive and XMM-Newton Science Archive. An example of the SIAP cone search for XMM-Newton is given in Figure 3.

**Figure 3:** XMM-Newton SIAP Cone Search, HTML and VOTABLE results
$\begin{figure} \epsscale{0.6} \plotone{D3_3.eps} \end{figure}$

3.2 SIAP Image Retrieval

The AIO SIAP Image Retrieval is using the standard AIO product server in a URL mode to pipe directly the standard data products to the requesting client. The default data products to be returned correspond to the highest level of automatically processed products.

4. Conclusions

The ISO Data Archive and XMM-Newton Science Archive offer flexible and powerful Inter-Operability services which allow to access directly archive metadata and data products.

These services are already compliant to the recent VO standard Simple Image Access Protocol and we have as well adapted them to support Simple Spectra Access by using similar mechanism.

These services are already widely used by ESA instrument experts and by external archives and applications and we foresee a more extensive use in the coming era of the Virtual Observatory and inter-operable archives.

Acknowledgments

The authors would like to acknowledge the rest of the ESA RSSD VILSPA Archive Development Team who have participated in the IDA and XSA development : John Dowson, Jose Hernandez, Inaki Ortiz, Guillermo San Miguel and Vrata Venet as well as the ISO and XMM-Newton Archive Scientists, Alberto Salama and Matteo Guainazzi.

References

Arviset, C. 2003, in ASP Conf. Ser., Vol. 295, Astronomical Data Analysis Software and Systems XII, ed. H. E. Payne, R. I. Jedrzejewski, & R. N. Hook (San Francisco: ASP), xii:O10-647

Osuna, P. 2004, this volume, 129