We present an analysis of ASCA spatially resolved spectroscopic data for a nearly complete sample of bright clusters with redshifts between 0.04 and 0.09 .
Together with several clusters analyzed elsewhere using the same method , this sample consists of 30 objects with T _ { e } \gtrsim 3.5 keV for which we obtained projected temperature profiles and , when possible , crude two-dimensional temperature maps .
The clusters are A85 , A119 , A399 , A401 , A478 , A644 , A754 , A780 , A1650 , A1651 , A1795 , A2029 , A2065 , A2142 , A2256 , A2319 , A2597 , A2657 , A3112 , A3266 , A3376 , A3391 , A3395 , A3558 , A3571 , A3667 , A4059 , Cygnus A , MKW3S , and Triangulum Australis .
All clusters , with the possible exception of a few with insufficiently accurate data , are found to be nonisothermal with spatial temperature variations ( apart from cooling flows ) by a factor of 1.3–2 . ASCA temperature maps for many clusters reveal merger shocks .
The most notable of these are A754 , A2065 , A3558 , A3667 , and Cygnus A ; merging can also be inferred with lower confidence from the A85 , A119 , and A2657 temperature maps and from the A3395 and Triangulum Australis entropy maps .
About half of the sample shows signs of merging ; in about 60 % of the sample , we detect cooling flows .
Nearly all clusters show a significant radial temperature decline at large radii .
For a typical 7 keV cluster , the observed temperature decline between 1 and 6 X-ray core radii ( 0.15 and 0.9 h ^ { -1 } Mpc ) can be approximately quantified by a polytropic index of 1.2–1.3 .
Assuming such a polytropic temperature profile and hydrostatic equilibrium , the gravitating mass within 1 and within 6 core radii is approximately 1.35 and 0.7 times the isothermal \beta -model estimates , respectively .

Most interestingly , we find that temperature profiles , excluding those for the most asymmetric clusters , appear remarkably similar when the temperature is plotted against radius in units of the estimated virial radius .
We compare the composite temperature profile to a host of published hydrodynamic simulations .
The observed profiles appear steeper than predictions of most Lagrangian simulations ( Evrard , Metzler , & Navarro 1996 ; Eke , Navarro , & Frenk 1997 ) .
The predictions for \Omega = 1 cosmological models are most discrepant , while models with low \Omega are closer to our data .
We note , however , that at least one \Omega = 1 Lagrangian simulation ( Katz & White 1993 ) and the recent high-resolution Eulerian simulation ( Bryan & Norman 1997 ) produced clusters with temperature profiles similar to or steeper than those observed .
Our results thus provide a new constraint for adjusting numerical simulations and , potentially , discriminating among models of cluster formation .