The gaseous atmosphere of M87 seen with XMM-Newton

Abstract

M87 is a key object whose study can reveal the complex phenomena in cooling cores. We use a deep XMM-Newton observation of M87 to produce detailed temperature, pressure and entropy maps in order to analyze the physical processes of cooling cores and of their heating mechanisms. We employed both broad-band fitting and full spectroscopical one-temperature model analysis to derive temperature and surface brightness maps, from which the pseudo-deprojected entropy and pressure were calculated. We discuss possible physical interpretations of small deviations from radial and elliptical symmetry in these maps. The most prominent features observed are the E and SW X-ray arms that coincide with powerful radio lobes, a weak shock at a radius of 3', an overall ellipticity in the pressure map and a NW/SE asymmetry in the entropy map which we associate with the motion of the galaxy towards the NW. For the first time we find evidence that cold, metal-rich gas is being transported out of the center, possibly through bubble-induced mixing. Several edges in the abundance map indicate an oscillation of the galaxy along the NW/SE direction. Furthermore, the radio lobes appear to rise along the short axis of the elliptical pressure distribution, following the steepest gradient of the gravitational potential, and seem to contain a nonthermal pressure component.