Volume 399, Number 2, February IV 2003
|Page(s)||497 - 504|
|Published online||07 February 2003|
High resolution soft X-ray spectroscopy of the elliptical galaxy NGC 5044
Results from the reflection grating spectrometer on-board XMM-Newton
SRON National Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Nether lands
2 Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
Corresponding author: T. Tamura, T.Tamura@sron.nl
Accepted: 27 November 2002
The results from an X-ray spectroscopic study of the giant elliptical galaxy NGC 5044 in the center of a galaxy group are presented. The line dominated soft X-ray spectra (mainly Fe-L and ) from the diffuse gas are resolved for the first time in this system with the Reflection Grating Spectrometers on-board XMM-Newton and provide a strong constraint on the temperature structure. The spectra integrated over 2´ (~20 kpc) in full-width can be described by a two temperature plasma model of 0.7 keV and 1.1 keV. Most of the latter component is consistent with originating from off-center regions. Compared to the isobaric cooling flow prediction, the observation shows a clear cut-off below a temperature of keV. Furthermore, the Fe and O abundances within the central 10–20 kpc in radius are accurately measured to be and times the solar ratios, respectively. The observed cut-off temperature of this galaxy and other central galaxies in galaxy groups and clusters are compared with the scale of the galaxy and properties of the surrounding intra-cluster medium. Based on this comparison, the origin of the lack of predicted cool emission is discussed.
Key words: galaxies: individual: NGC 5044 / galaxies: clusters: general / galaxies: abundances / X-rays: galaxies: clusters
© ESO, 2003
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