The German ROSAT XUV Data Center and a ROSAT XUV Pointed Phase Source Catalogue

R. Staubert, H. Brunner,¹ H.-C. Kreysing

Institut für Astronomie und Astrophysik, Astronomie, Universität Tübingen, Waldhäuser Str. 64, D-72076 Tübingen, Germany

¹Now at Astrophysikalisches Institut Potsdam, Germany

Abstract:

1. Introduction

The Wide Field Camera (WFC) onboard the ROSAT satellite is a telescope sensitive in the extreme UV range (17--210eV) and observes in parallel with the main X-Ray Telescope (XRT). The German XUV Data Center (GXUVDC) for ROSAT operated at the University of Tübingen is responsible for the distribution of observational data from the WFC during the pointed phase of the ROSAT mission to investigators in Germany. In addition, a public archive is kept which can be accessed remotely. All incoming data are subject to a Standard Analysis (Brunner & Kreysing 1993), the results of which are forwarded to the respective investigators together with the original data. A general description of data products from the ROSAT mission is given in Zimmermann et al.\ (1994a). The GXUVDC also concerns itself with a statistical analysis of all archived data. We describe the operations of the GXUVDC and its archive. We also briefly describe the ROSAT XUV Pointed Phase Source Catalogue (Kreysing, Brunner, & Staubert 1995) which has resulted from this activity.

2. Duties and History

In Table 1 we list the duties of the data center and in Table 2 some dates of key events are given.

Table 1: Duties of the ROSAT/XUV Data Center

reformat the German pointed WFC data to be compatible with the ROSAT software system EXSAS (Extended Scientific Analysis System) (Zimmermann et al. 1994b) and distribute them to the respective PIs on FITS tapes (data tapes are mailed for those observations where sources are detected)

perform a Standard Analysis on all incoming data (automatic source search, variability analysis, ...)

maintain a public archive of all pointed ROSAT/WFC observations (images and maps of all pointed WFC observations are available on-line).

Table 2: Time Table of ROSAT/XUV DATA Center Activities

3. A ROSAT XUV Pointed Phase Source Catalogue

On the basis of the archive containing the results of the Standard Analysis a ROSAT XUV Pointed Phase Source Catalogue has recently been compiled (Kreysing, Brunner, & Staubert 1995). 5916 pointed observations were processed from the calibration and verification phase in June 1990 and from the period 9 February 1991 to 15 July 1994. The catalogue contains 1022 independent source detections which correspond to 328 individual sources, many of which have been observed repeatedly. Each observation was done with one of four filters S1, S2, P1 and P2. Of the 328 sources 113 are new sources [they are not listed in the ``2RE'' catalogue (Pye et al.\ 1995) giving the result of the All Sky Survey] and 274 have been identified with optical counterparts. The catalogue contains coordinates, observed count rates, normalized source count rates and the proposed optical counterpart with its spectral class. For observations with filters S1 and S2 an in-flight calibration has been applied using data of White Dwarfs which were assumed to have a constant flux and which were observed repeatedly (in pointed observations and/or during the All Sky Survey). In this way, it was possible to correct for the time dependent degradation of the detector efficiency and to normalize the count rates to those valid at the beginning of the mission. A summary of relevant numbers is given in Tables 3 and 4. The complete catalogue as well as the text and figures from the accompanying paper by Kreysing, Brunner and Staubert (1995) may be downloaded from the public WFC archive (see Section 4).

Table 3: WFC Data Processing Summary

Table 4: Break Up of Detected Sources by Category

4. The ROSAT WFC Public Archive

A public archive of all WFC data (including those originally assigned to the UK or USA) is maintained at the Institute of Astronomy and Astrophysics, Astronomy Division, at the University of Tübingen. Below we list the items available on the archive account for on-line inspection or downloading. EXSAS compatible FITS tapes and printouts of the Standard Analysis will be mailed to interested observers on request.
The following products are available in the on-line archive (data and results):
Observation log
Downloadable compressed full images and maps (FITS)
Count rates and source positions
SIMBAD source identifications
Text, Figures and Tables of ``A ROSAT XUV Pointed Phase Source Catalogue'' (Kreysing, Brunner, & Staubert 1995)

Access to the archive is provided through the following channels and addresses:
TELNET: ait.physik.uni-tuebingen.de
FTP: ait.physik.uni-tuebingen.de
Login: XUV Password: XUV_ARCHIVE
WWW: http://astro.uni-tuebingen.de/rosat.html
SPAN: 29382::XUV_ARCHIVE:[XUV]

See also details in ROSAT News 19 and README.TXT in archive. For special problems or requests J. Schaumberger may be contacted at
GXUVDC@ait.physik.uni-tuebingen.de
or
29382::GXUVDC

Acknowledgments:

We acknowledge valuable contributions by J. Schaumberger.

References:

Kreysing, H. C., Brunner, H., & Staubert, R. 1995, A&AS, in press

Pounds, K. A., Allen, D. J., Barber, C., et al. 1993, MNRAS, 260, 77

Pye, J. P., Mc Gale, P. A., Allan, D. J., et al. 1995, MNRAS, 274, 1165

Zimmermann, H. U., Brunner, H., Pisarski, R., Voges, W., Watson, M. 1994a, in Databases & On-line Data in Astronomy, eds. Albrecht & Egret (Kluwer), 1994

Zimmermann, H. U., Becker, W., Belloni, T., et al. 1994b, EXSAS User's Guide, MPE Reprt 257, MPE Garching