Date:
-
Location:
CP179
Speaker(s) / Presenter(s):
Marios Chatzikos (University of Kentucky)
The nature of cooling in galaxy cluster has been puzzling since cool core clusters were first discovered. Even though early X-ray observations suggested copious amount of cooling, optical observations failed to detect star formation at the levels suggested by X-rays. More recently, dispersed spectroscopy with Chandra and XMM-Newton has revealed a dearth of gas below 1/3 of the mean cluster temperature. Heating mechanisms have been invoked to account for the temperature floor and residual star formation, but the details remain unclear. Probes for the hot X-ray (~10 MK), cool optical (~10,000 K), and intermediate temperature (~100,000 -- 1 million K) phases are necessary to unravel the balance between heating and cooling in clusters. Recently, coronal line emission from gas of ~1 million K has been reported near NGC 4696, the Brightest Cluster Galaxy in the Centaurus galaxy cluster. By contast, gas at 2 million K was not detected. In this talk I build upon a new facility in Cloudy that allows for time-dependent, non-advective simulations. I use this capability to follow a parcel of gas as it cools from ~80 MK to ~10,000 K. I show that the lack of 2 million K gas is not due to extinction. I use the observed upper limit to place an upper limit to the temperature of the coronal gas, and find that, if the gas is cooling, it is cooling isochorically. I discuss scenarios for the origin of the coronal gas, and propose observational probes for gas at temperatures between a million and 10,000 K, that could shed some light into cooling processes in galaxy clusters.
Event Series: