The cooling flow cluster Hydra A was observed during the orbital activation and calibration phase of the Chandra Observatory .
While the X-ray image of the cluster exhibits complex structure in the central region as reported in McNamara etal , the large scale X-ray morphology of the cluster is fairly smooth .
A spectroscopic analysis of the ACIS data shows that the gas temperature in Hydra A increases outward , reaches a maximum temperature of 4 keV at 200 kpc , and then decreases slightly at larger radii .
The distribution of heavy elements is nonuniform , with a factor of two increase in the Fe and Si abundances within the central 100 kpc .
Beyond the central 100 kpc the Si-to-Fe abundance ratio is twice solar , while the Si-to-Fe ratio of the central excess is consistent with the solar value .
One of the more surprising results is the lack of spectroscopic evidence for multiphase gas within the bulk of the cooling flow .
Beyond the central 30 kpc , the ACIS spectra are adequately fit with a single temperature model .
The addition of a cooling flow component does not significantly improve the fit .
Only within the central 30 kpc ( where the cooling time is less than 1 Gyr ) , is there spectroscopic evidence for multiphase gas .
However , the spectroscopic mass deposition rate is more than a factor of 10 less than the morphologically derived mass accretion rate at 30 kpc .
We propose that the cooling flow region is convectively unstable due to heating by the central radio source which significantly reduces the net accretion rate .
In addition , we show that the mass distribution within the central 30-200 kpc region scales as \rho _ { d } \propto r ^ { -1.3 } , intermediate between an NFW and Moore profile , but with a best-fit NFW concentration parameter ( c _ { NFW } = 12 ) approximately 3 times greater than that found in numerical simulations .
However , given the limited photon statistics , we can not rule out the presence of a flat-density core with a core radius less than 30 kpc .