The cluster M-T relation from temperature profiles observed with ASCA and ROSAT

We calibrate the galaxy cluster mass-temperature (M-T) relation using the temperature profiles of intracluster gas observed with ASCA (for hot clusters) and ROSAT (for cool groups). Our sample consists of apparently relaxed clusters for which the total masses are derived, assuming hydrostatic equilibrium. The sample provides data on cluster X-ray emission-weighted cooling-flow-corrected temperatures and total masses up to r(1000). The resulting M-T scaling in the 1-10 keV temperature range is M-1000 = (1.23 +/- 0.20) 10(15) h(50)(-1) M.(< T >(z=0)/10 keV)(1.79 +/- 0.14) with 90% confidence errors, or significantly (99.99% confidence) steeper than the self-similar relation M proportional to T-3/2. For any given temperature, our measured mass values are significantly smaller compared to the simulation results of Evrard, Metzler, & Navarro that are frequently used for mass-temperature scaling. The higher temperature subsample (kT greater than or equal to 4 keV) is consistent with M proportional to T-3/2, allowing the possibility that the self-similar scaling breaks down at low temperatures, perhaps due to heating by supernovae that is more important for low-temperature groups and galaxies, as suggested by earlier works.