We present a multiwavelength analysis of a sample of four hot ( T _ { X } > 8 { keV } ) X-ray galaxy clusters ( A1689 , A2261 , A2142 , and A2390 ) using joint AMiBA Sunyaev-Zel ’ dovich effect ( SZE ) and Subaru weak lensing observations , combined with published X-ray temperatures , to examine the distribution of mass and the intracluster medium ( ICM ) in massive cluster environments .
Our observations show that A2261 is very similar to A1689 in terms of lensing properties .
Many tangential arcs are visible around A2261 , with an effective Einstein radius \sim 40 \arcsec ( at z \sim 1.5 ) , which when combined with our weak lensing measurements implies a mass profile well fitted by an NFW model with a high concentration c _ { vir } \sim 10 , similar to A1689 and to other massive clusters .
The cluster A2142 shows complex mass substructure , and displays a shallower profile ( c _ { vir } \sim 5 ) , consistent with detailed X-ray observations which imply recent interaction .
The AMiBA map of A2142 exhibits an SZE feature associated with mass substructure lying ahead of the sharp north-west edge of the X-ray core suggesting a pressure increase in the ICM .
For A2390 we obtain highly elliptical mass and ICM distributions at all radii , consistent with other X-ray and strong lensing work .
Our cluster gas fraction measurements , free from the hydrostatic equilibrium assumption , are overall in good agreement with published X-ray and SZE observations , with the sample-averaged gas fraction of \langle f _ { gas } ( < r _ { 200 } ) \rangle = 0.133 \pm 0.027 , for our sample with \langle M _ { vir } \rangle = ( 1.2 \pm 0.1 ) \times 10 ^ { 15 } M _ { \odot } h ^ { -1 } .
When compared to the cosmic baryon fraction f _ { b } = \Omega _ { b } / \Omega _ { m } constrained by the WMAP 5-year data , this indicates \langle f _ { gas, 200 } \rangle / f _ { b } = 0.78 \pm 0.16 , i.e. , ( 22 \pm 16 ) % of the baryons are missing from the hot phase of clusters .