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 O viii { Ly \alpha } ) 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′ ( \sim 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 0.6 \pm 0.1 keV .
Furthermore , the Fe and O abundances within the central 10–20 kpc in radius are accurately measured to be 0.55 \pm 0.05 and 0.25 \pm 0.1 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 .