XMM-Newton observation of the galactic centre – evidence against the X-ray reflection nebulae model?
✍ Scribed by P. Predehl; E. Costantini; G. Hasinger; Y. Tanaka
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 460 KB
- Volume
- 324
- Category
- Article
- ISSN
- 0004-6337
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✦ Synopsis
Abstract
We present preliminary results of a 50 ksec XMM‐Newton observation of the Galactic Centre. Due to the excellent spectral resolution of XMM‐Newton combined with its high throughput at energies even beyond 7 keV, the iron line complex could be resolved into individual components (neutral, ionized, both in K__α__ and K__β__) in the spectra of a number of sources. In the spectrum of Sgr A East, we find an overabundance of iron, although less than reported in a recent analysis of Chandra data. No flare from Sgr A*was detected. The large scale diffuse emission seen already by Einstein, ROSAT, and ASCA extending into the north‐east direction is most probably of thermal origin. This region extends from Sgra A East also towards both directions perpendicular to the Galactic Plane (“outflow”) and contains some blobs of plasma with a higher temperature. Particularly interesting is the map of the 6.4 keV fluorescence line of neutral iron which shows a very peculiar filamentary structure. Spectral modelling of these filaments is obviously not in agreement with the X‐ray reflection nebulae (XRN) model commonly discussed for the origin of the fluorescence line, primarily because we do not see a significant iron absorption edge at 7.1 keV.