Feedback under the microscope: heating, gas uplift, and mixing in the nearest cluster core
Abstract
Using a combination of deep Chandra data, XMM-Newton high-resolution spectra, and optical Hα+[NII] images, we study the nature and spatial distribution of the multiphase plasma in M87. Our results provide direct observational evidence of 'radio-mode' AGN feedback in action, stripping the central galaxy of its lowest entropy gas and thereby inhibiting star formation. This low entropy gas was entrained with and uplifted by the buoyantly rising relativistic plasma. With Chandra's exquisit spatial resolution and deep exposure, we place the best constraints to date on the mass of uplifted gas and mechanical energy associated with this uplift. The coolest X-ray emitting gas in M87 has a temperature of 0.5 keV and is spatially coincident with Hα+[NII] nebulae. Strong upper limits on the mass of gas below 0.5 keV rule out feedback through any uniform, volume-averaged heating mechanism. All the bright Hα filaments appear in the downstream region of a 3 Myr old shock front. We suggest that shocks induce shearing around the filaments, promoting mixing of the cold gas with the ICM via instabilities. This powers the optical spectra and allows the ICM to cool non-radiatively, explaining the lack of X-ray gas with temperatures below 0.5 keV.
- Publication:
-
38th COSPAR Scientific Assembly
- Pub Date:
- 2010
- Bibcode:
- 2010cosp...38.2626S