We selected an unbiased , flux-limited and almost volume-complete sample of 13 distant , X-ray luminous ( DXL , z \sim 0.3 ) clusters and one supplementary cluster at z = 0.2578 from the REFLEX Survey ( the REFLEX-DXL sample ) .
We performed a detailed study to explore their X-ray properties using XMM-Newton observations .
Based on the precise radial distributions of the gas density and temperature , we obtained robust cluster masses and gas mass fractions .
The average gas mass fraction of the REFLEX-DXL sample at r _ { 500 } , 0.116 \pm 0.007 , agrees with the previous cluster studies and the WMAP baryon fraction measurement .
The scaled profiles of the surface brightness , temperature , entropy , gas mass and total mass are characterized by a self-similar behaviour at radii above 0.2–0.3 r _ { 500 } .
The REFLEX-DXL sample confirms the previous studies of the normalization of the scaling relations ( L – T , L – M , M – T and M _ { gas } – T ) when the redshift evolution of the scaling relations is accounted for .
We investigated the scatter of the scaling relations of the REFLEX-DXL sample .
This gives the correlative scatter of ( 0.20,0.10 ) for variable of ( M , T ) of the M _ { 500 } – T relation , for example .

osmology : observations – Galaxies : clusters : general – X-rays : galaxies : clusters – ( Cosmology : ) dark matter