Chandra X - ray observations of the 3 C 295 cluster core

We examine the properties of the X-ray gas in the central regions of the distant (z = 0.46), X-ray luminous cluster of galaxies surrounding the powerful radio source 3C295, using observations made with the Chandra Observatory. Between radii of 50−500 kpc, the cluster gas is approximately isothermal with an emission-weighted temperature, kT ∼ 5 keV. Within the central 50 kpc radius this value drops to kT ∼ 3.7 keV. The spectral and imaging Chandra data indicate the presence of a cooling flow within the central 50 kpc radius of the cluster, with a mass deposition rate of approximately 280 M ⊙ yr −1. We estimate an age for the cooling flow of 1−2 Gyr, which is approximately one thousand times older than the central radio source. We find no evidence in the X-ray spectra or images for significant heating of the X-ray gas by the radio source. We report the detection of an edge-like absorption feature in the spectrum for the central 50 kpc region, which may be due to oxygen-enriched dust grains. The implied mass in metals seen in absorption could have been accumulated by the cooling flow over its lifetime. Combining the results on the X-ray gas density profile with radio measurements of the Faraday rotation measure in 3C295, we estimate the magnetic field strength in the region of the cluster core to be B ∼ 12µG.