Hot and cold bubbles in M87

Hot and cold bubbles in M 87

The X-ray data obtained with XMM-Newton is used to investigate the complex structure of the gas in the atmosphere of the Virgo cluster around M87. We construct a simple model for the temperature and density distribution. This model implies that the cumulative mass of the cluster gas is a power-law of its entropy index, kT n−2/3, similar to the Hydra cluster. This supports the idea that such pow...

Is the Plasma within Bubbles and Superbubbles Hot or Cold?

Is the Plasma within Bubbles and Superbubbles Hot or Cold?

I review what is known about the temperature of the plasma within stellar wind bubbles and superbubbles. Classical theory suggests that it should be hot, with characteristic temperatures of order a million degrees. This temperature should be set by the balance between heating by the internal termination shocks of the central stellar winds and supernovae, which expand at thousands of km s, and c...

Cold and hot.

Parity Odd Bubbles in Hot Qcd

We consider the topological susceptibility for an SU(N) gauge theory in the limit of a large number of colors, N → ∞. At nonzero temperature, the behavior of the topological susceptibility depends upon the order of the deconfining phase transition. The most interesting possibility is if the deconfining transition, at T = Td, is of second order. Then we argue that Witten’s relation implies that ...