Recent Dynamical Relaxation of Galaxy Clusters: Evidence for a Low-Ωm Universe
نویسندگان
چکیده
We argue that there has been substantial evolution in the ellipticity of rich galaxy clusters between 0 < z < 0.1, and suggest that this is additional evidence for a low matter-density Universe. Subject headings: cosmology: large-scale structure of universe – galaxy clusters: evolution
منابع مشابه
Cosmological constraints from the local X - ray luminosity function of the most X - ray luminous galaxy clusters
We present precise constraints on the normalization of the power spectrum of mass fluctuations in the nearby universe, σ8, as a function of the mean local matter density, Ωm. Using the observed local X-ray luminosity function of galaxy clusters from the extended BCS and REFLEX studies, a mass-luminosity relation determined from Chandra and ROSAT X-ray data and weak gravitational lensing observa...
متن کاملBaryon Crisis and Cluster Mass Estimates
I report the current status on the determinations of the baryon fractions and dynamical/lensing masses of galaxy clusters as well as the σ T relationship, making use of all the published data in literature which include 304 measurements for baryon fractions, 320/21 data points for masses of intracluster gas/cluster galaxies, (152+228)/72 data points for cluster masses derived from X-ray emittin...
متن کاملDynamical effects on galaxies in clusters
The observed morphological evolution since z ∼ 0.5 within galaxy clusters provides evidence for a hierarchical universe. This evolution is driven by dynamical effects that operate within the cluster environment – suppression of star-formation by ram-pressure and viscous stripping of the intra-galactic medium and tidal heating of disks by grav-itational encounters. 1. Evidence for a hierarchical...
متن کاملΩm from the Temperature-Redshift Distribution of EMSS Clusters of Galaxies
We constrain Ωm through a maximum likelihood analysis of temperatures and redshifts of the high-redshift clusters from the EMSS. We simultaneously fit the low-redshift Markevitch (1998) sample (an all-sky sample from ROSAT with z = 0.04 − 0.09), a moderate redshift EMSS sample from Henry (1997) (9 clusters with z = 0.3 − 0.4), and a more distant EMSS sample (5 clusters with z = 0.5 − 0.83 from ...
متن کاملFaint End of the Galaxy Luminosity Function: A Chronometer for Structure Formation?
There is accumulating evidence that the faint end of the galaxy luminosity function might be very different in different locations. The luminosity function might be sharply rising in rich clusters and flat or declining in regions of low density. If galaxies form according to the model of hierarchical clustering then there should be many small halos compared to the number of big halos. If this t...
متن کامل