Filaments, Bubbles, and Weak Shocks in the Gaseous Atmosphere of M87

We present the first results from a 500 ksec Chandra ACIS-I observation of M87. At soft energies (0. 5-1. 0 keV), we detect a complex filamentary structure associated with the eastern and southwestern arms. Many filaments are spatially resolved and have widths of ~300 pc. This filamentary structure is particularly striking in the eastern arm where we suggest the filaments are outer edges of a series of buoyant bubbles filled with relativistic plasma, produced by the central supermassive black hole, in a succession of small outbursts occurring every ~6 x 10⁶ years. The X-ray structures may be influenced by magnetic filamentation. At hard energies (3. 5-7. 5 keV), we detect a nearly circular shell of outer radius 2. 8' (13 kpc). This ring of hard X-ray emission provides an unambiguous signature of a weak shock, driven by an outburst from the SMBH, traversing the M87 atmosphere. The observed spectral hardening corresponds to a temperature rise from 2. 0 to 2. 4 keV, which translates to a Mach number M~1. 2 for monoatomic gas with gamma=5/3. In addition, we detect two additional surface brightness edges (at radii of ~0. 6' and ~1. 2'). The ~0. 6' feature may be the gas just outside the ``piston'' driving the 2. 8' shock, while the ~1. 2' feature is probably produced by a secondary outburst.