Proprieties of clumps and filaments around galaxy clusters

Missing baryons in shells around galaxy clusters

Aims. The cluster baryon fraction is estimated from the CMB-scattering leptonic component of the intracluster medium (ICM); however, the observed cluster baryon fraction is less than the cosmic one. Understanding the origin of this discrepancy is necessary for correctly describing the structure of the ICM. Methods. We estimate the baryonic mass in the outskirts of galaxy clusters which is diffi...

Testing gravity with the stacked phase space around galaxy clusters.

In general relativity, the average velocity field of dark matter around galaxy clusters is uniquely determined by the mass profile. The latter can be measured through weak lensing. We propose a new method of measuring the velocity field (phase space density) by stacking redshifts of surrounding galaxies from a spectroscopic sample. In combination with lensing, this yields a direct test of gravi...

Hard X-ray Emission from Accretion Shocks around Galaxy Clusters

We show that the hard X-ray (HXR) emission observed from several galaxy clusters is naturally explained by a simple model, in which the nonthermal emission is produced by inverse Compton scattering of cosmic microwave background photons by electrons accelerated in cluster accretion shocks: The dependence of HXR surface brightness on cluster temperature is consistent with that predicted by the m...

A Mapping Survey of Dense Clumps Associated with Embedded Clusters : Evolutionary Stages of Cluster-Forming Clumps

We have carried out a survey of the dense clumps associated with 14 embedded clusters in the CO (J=1–0) line emission with the Nobeyama 45m telescope in order to understand the formation and evolution of stellar clusters in dense clumps of molecular clouds. We have selected these clusters at distances from 0.3 to 2.1 kpc and have mapped about 6 × 6 to 10 × 10 regions (corresponding to 3.8 pc × ...

Galaxy Clusters