| Type |
Journal Article |
| Names |
W. Forman, C. Jones, E. Churazov, M. Markevitch, P. Nulsen, A. Vikhlinin, M. Begelman, H. Böhringer, J. Eilek, S. Heinz, R. Kraft, F. Owen, M. Pahre |
| Publication |
The Astrophysical Journal |
| Volume |
665 |
| Issue |
2 |
| Pages |
1057-1066 |
| Date |
August 1, 2007 |
| URL |
http://adsabs.harvard.edu/abs/2007ApJ...665.1057F |
| Library Catalog |
NASA ADS |
| Abstract |
We present the first results from a 500 ks Chandra ACIS-I observation of
M87. At soft energies (0.5-1.0 keV), we detect filamentary structures
associated with the eastern and southwestern X-ray and radio arms. Many
filaments are spatially resolved with 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 plasma-filled,
buoyant bubbles whose ages differ by ~6×106 yr. These
X-ray structures may be influenced by magnetic filamentation. At hard
energies (3.5-7.5 keV), we detect a nearly circular ring of outer radius
2.8' (13 kpc), which provides an unambiguous signature of a weak shock,
driven by an outburst from the supermassive black hole (SMBH). The
density rise in the shock is ρshock/ρ0~1.3
(Mach number, M~1.2). The observed spectral hardening in the ring
corresponds to a temperature rise Tshock/T0~1.2,
or M~1.2, in agreement with the Mach number derived independently from
the gas density. Thus, for the first time, we detect gas temperature and
density jumps associated with a classical shock in the atmosphere around
a SMBH. We also detect two additional surface brightness edges and
pressure enhancements at radii of ~0.6' and ~1'. The ~0.6' feature may
be overpressurized thermal gas surrounding the relativistic plasma in
the radio cocoon, the ``piston,'' produced by the current episode of AGN
activity. The overpressurized gas is surrounded by a cool gas shell. The
~1' feature may be an additional weak shock from a secondary outburst.
In an earlier episode, the piston was responsible for driving the 2.8'
shock. |
| Tags |
GALAXIES: INDIVIDUAL: MESSIER NUMBER: M87, Galaxies: Individual: NGC Number: NGC 4486, X-rays: galaxies, galaxies: active |