Gravitational potentials of nearby, massive elliptical galaxies

Churazov, E., Forman, W., Vikhlinin, A., Tremaine, S., Gerhard, O., Jones, C. 2008, MNRAS, 388, 1062  (to the paper)

Massive ellipticals harbour a hot (T ~ 1 keV) interstellar medium (ISM) in the form of a low density (n < 0.1 cm-3) plasma trapped in the galaxy's gravitational potential. In massive ellipticals, the observed X-ray spectrum is dominated by emission from the ISM primarily via thermal bremsstrahlung and X-ray lines of heavy elements (Forman et al., 1985). In quiescent galaxies, where the gas is not significantly distorted by interactions with companion galaxies, one can assume hydrostatic equilibrium and use the temperature and density profiles derived from X-ray spectra to obtain a mass profile (e.g., Fukazawa et al., 2006). Churazov et al. (2008) obtain the potential of NGC 1399 and M87 and compare their profiles with that found in stellar dynamical models.