Published in Astrophysical Journal Vol.485 (1997), pp.125-135
ContentsIntroduction SXRB Maps Descriptions Data Format Processing Update Data Analysis Supplements Bright Source Catalog SXRB exposure map Leiden/Dwingeloo 21 cm maps Astronomy Abstract Service
[Reference for image: M.J.Freyberg, R.Egger (1999), dto, Fig.1b]
The paper (ApJ 485, 125) presents an updated version of the diffuse background results from the ROSAT soft X-ray all-sky survey. The maps cover approximately 98% of the sky in the 1/4 keV, 3/4 keV, and 1.5 keV bands, divided into 2 bands each (R1+R2, R4+R5, R6+R7, respectively) with about 12 arcmin angular resolution and high sensitivity for low surface brightness extended features. The effects of non-X-ray contamination and X-rays of solar system origin have been eliminated to the greatest possible extent, but discrete X-ray sources have not been removed. The much improved angular resolution, statistical precision, and completeness of coverage of these maps reveals considerable structure over the entire 0.1 - 2.0 keV energy range that was not observed previously. The data compare well with previous all-sky surveys in terms of absolute normalization and zero point.
Here we present the data of Figs.2a-f, 3a-f, and 4a-f in electronic format (FITS). Maps were constructed using an equal-area polar projection. They contain 512 x 512 pixels with size 12' x 12'. Intensities are in units 10**(-6) counts/second/arcmin**2, exposure times in seconds. Galactic coordinates are used throughout, with longitude 0 centered and increasing to the left.
You may use these maps for scientific purposes as long as reference is made to the relevant publication:
S.L. Snowden, R.Egger, M.J. Freyberg, P.P. Plucinsky, J.H.M.M. Schmitt, J. Trümper, W. Voges, D. McCammon, W.T. Sanders: Astrophysical Journal, Vol.485 (1997), pp.125-135
If you reproduce the GIF images, please, do not alter these. Any comments, suggestions, problem reports etc. concerning the distribution of the electronic maps should be directed to:
Michael Freyberg, MPE, Postfach 1603, D-85740 Garching, Germany email: mjf (at) mpe . mpg . de (Michael Freyberg)
[Reference for image: M.J.Freyberg, R.Egger (1999), dto, Fig.1c]
SXRB MapsMaps of the Soft X-ray Diffuse Background from the ROSAT XRT/PSPC All-Sky Survey are available in six energy bands, in FITS as well as in GIF format. Clicking on the small images will display full-size (842*595) versions (140 kB). If you want to directly download the files set your browser to "load to local disk..." Goto the map page ...
[Reference for image: M.J.Freyberg, R.Egger (1999), dto, Fig.1d]
DescriptionsData format: The six centers (poles) for the projections are the north and south galactic poles and at l = 0°, 90°, 180°, 270° along the plane. All maps are Zenith Equal Area projections in galactic coordinates with about 100 x 100 degrees. Longitude is increasing to the left. The maps are arrays of size 512*512 pixels (REAL*4) with pixel size 12*12 arcmin**2. They contain a header (almost) compatible with the standard EXSAS header. However, some descriptor values are not yet fully implemented in the EXSAS package. An ASCII list of FITS header is also available. World coordinates are given in sky pixels (size 0.5 arcsec). Units of the intensity maps (Figs.2 - 4) for the six energy bands are 10**(-6) counts per second per arcmin**2. Processing: The user is asked to consult Sects.2.2 and 3 of ApJ 454, 643 (40 arcmin resolution) and Sects.2 and 3 of ApJ 485, 125 for a full description of the processing and data reduction to avoid misleading scientific conclusions. Here only a summary is given: - SASS data used: OMAS - PI channels (corrected amplitude) - effective angular resolution is 12 arcmin - sources excluded (Rev0 source list) - particle background, scattered solar X-rays, long-term enhance- ments subtracted, excess contamination times excluded Update: We have prepared an update to the description in ApJ 454, 643 and ApJ 485, 125. It is available in PostScript format. Data analysis: The data files in FITS format can be analysed using the EXSAS/MIDAS software package which is freely available from MPE. There is a lot of documentation on X-ray analysis software at MPE. You can find there the home page of the EXSAS group with the most recent version of the EXSAS Users Guide (July 1998) and the software package itself. EXSAS is built on ESO-MIDAS.