M87: the Radio Halo and the Virgo Core
Radio galaxies in the cores of clusters of galaxies are unusual.
Most radio galaxies are established on large scales by the
interaction of a collimated jet with the ambient medium. However, in
the centers of some clusters it appears that the cluster gas has disrupted
the radio jet, leading to an unusual, amorphous radio galaxy. M87, the
nearby radio galaxy in the Virgo cluster, is an example of this.
VLA image of the inner radio lobes of M87; the scale is 5 kpc.
On small scales, this active galaxy contains a well-collimated jet (visible
in the optical as well as the radio). This jet appears to end a few kpc
from the galactic core. The source also has a much larger, diffuse halo.
Bright regions connect the inner lobes to this larger halo; these are very
likely plasma flows, which supply the full halo with mass and energy from
the core. We suspect that unusual conditions in the surrounding thermal
gas have disrupted the jet and led to the production of this "bubble-like"
radio halo
VLA image of the radio halo of M87; the scale is 80 kpc.
My work here is in collaboration with F.N. Owen
(NRAO) and F. Zhou
(NMTech)
References:
- The Outer Radio Halo: Typical of
Atypical Radio Sources?
- Magnetic Fields and Turbulence in
M87
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