The gaseous atmosphere of M 87 seen with XMM-Newton

¹ Max-Planck-Institute for Extraterrestial Physics, Giessenbachstr, 85748 Garching, Germany e-mail: aurora@mpe.mpg.de
² International University Bremen, Campus Ring 1, 28759 Bremen, Germany
³ University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA

Received: 27 October 2006
Accepted: 28 December 2006

Abstract

Aims.M 87 is a key object whose study can reveal the complex phenomena in cooling cores. We use a deep XMM-Newton observation of M 87 to produce detailed temperature, pressure and entropy maps in order to analyze the physical processes of cooling cores and of their heating mechanisms.

Methods.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.

Results.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 outwards also outside the X-ray arms, 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.