Conveners
Wednesday morning
- Daisuke Nagai (Yale University)
Dr
Christoph Pfrommer
(HITS)
13/08/2014, 09:00
Program
Feedback by active galactic nuclei appears to be critical in balancing radiative cooling of the low-entropy gas at the centers of galaxy clusters and in mitigating the star formation of the brightest cluster galaxies. I consider a model where the heating is provided by the damping of Alfvén waves that are excited by streaming cosmic rays (CRs). Recent radio observations of M87 by LOFAR suggest...
Dr
Eugene Churazov
(MPA)
13/08/2014, 09:25
Program
Measurements of gas density fluctuations in galaxy clusters using X-ray images are discussed. We argue that for relaxed clusters there is a linear relation between the rms density and velocity fluctuations across a broad range of scales. The normalization of this relation can be predicted, provided that the gas motions are slow enough. The normalization is set at large scales by buoyancy...
Prof.
Tom Jones
(U Minnesota)
13/08/2014, 09:50
Program
Turbulence in the ICM is a natural consequence of shocks and large-scale sheared flows produced in structure formation during mergers and from accretion, more generally. This is demonstrated in many simulations. However, the physical conditions involved in turbulence generation and evolution in this context are complex and intermittent in both time and space. Consequently they and their...
Ms
Kaylea Nelson
(Yale University)
13/08/2014, 11:00
Program
Cosmological constraints from X-ray and microwave observations of galaxy clusters are subjected to systematic uncertainties. Non-thermal pressure support due to internal gas motions in galaxy clusters is one of the major sources of astrophysical uncertainties. Using mass-limited samples of galaxy clusters from high-resolution hydrodynamical cosmological simulations, we characterize the...
Elena Rasia
(University of Michigan)
13/08/2014, 11:25
Program
Analyses of cosmological hydrodynamic simulations of galaxy clusters suggest that X-ray masses can be un- derestimated by 10% to 30%. The largest bias originates by both violation of hydrostatic equilibrium and an additional temperature bias caused by inhomogeneities in the X-ray emitting intra-cluster medium (ICM). To elu- cidate on this large dispersion among theoretical predictions, we...
