The spectral signature of the cooling flow in Abell 478.

Abstract

We present X-ray spectra of Abell 478 taken with the Ginga LAC and with the Einstein SSS. The LAC data set an upper limit of ~440 M_sun_ yr^-1^ on the mass deposition rate throughout the whole cluster if a value for the galactic absorption based on 21-cm observations of H I is adopted. The SSS data strongly require an absorbing column density well in excess of that expected by scaling from 21 -cm observations of galactic H I. Data from the LAC, SSS and HRI taken together imply a mass deposition rate of about 1000 M_sun_ yr^-1^ with an absorption column density ~4.8 x 10^21^ cm^-2^. The excess absorption may be intrinsic to the cooling flow or due to structure in the interstellar medium of the Galaxy on a scale smaller than the grid of 21 -cm observations.