We present an X-ray analysis of the rich cluster ABCG 85 based on ROSAT PSPC data .
By applying an improved wavelet analysis , we show that our view of this cluster is notably changed from what was previously believed ( a main region and a south blob ) .
The main emission comes from the central part of the main body of the cluster on which is superimposed that of a foreground group of galaxies .
The foreground group and the main cluster are separated ( if redshifts are cosmological ) by 46 h _ { 50 } ^ { -1 } Mpc .
The southern blob is clearly not a group : it is resolved into X-ray emitting galaxies ( in particular the second more luminous galaxy of the main cluster ) .
Several X-ray features are identified with bright galaxies .
We performed a spectral analysis and derived the temperature ( T ) , metallicity ( Z ) and hydrogen column density ( N _ { H } ) .
The global quantities are : T=4 keV ( in agreement with the velocity dispersion of 760 km/s ) and Z=0.2Z _ { \odot } .
We can not derive accurate gradients for these quantities with our data , but there is strong evidence that the temperature is lower ( \sim 2.8 keV ) and the metallicity much higher ( Z \sim 0.8 Z _ { \odot } ) in the very centre ( within about 50 h _ { 50 } ^ { -1 } kpc ) .
We present a pixel by pixel method to model the physical properties of the X-ray gas and derive its density distribution .
We apply classical methods to estimate the dynamical , gas and stellar masses , as well as the cooling time and cooling flow characteristics .
At the limiting radius of the image ( 1.4 h _ { 50 } ^ { -1 } Mpc ) , we find M _ { Dyn } \sim ( 2.1 - 2.9 ) 10 ^ { 14 } h _ { 50 } ^ { -1 } M _ { \odot } , M _ { gas } /M _ { Dyn } \sim 0.18 h _ { 50 } ^ { -1.5 } .
The stellar mass is 6.7 10 ^ { 12 } M _ { \odot } , giving a mass to light ratio of M/L _ { V } \sim 300 .
The cooling time is estimated for different models , leading to a cooling radius of 30-80 kpc depending on the adopted cluster age ; the mass deposit rate is 20-70 M _ { \odot } /yr , lower than previous determinations .
These results are discussed ( cooling flow paradigm in relation with high Z , ‘ baryonic crisis ’ etc . )
in connection with current ideas on dynamical and evolutionary properties of clusters .