1994/06/11 by A. E. Evrard, August E. Evrard, Evrard, August E.
Physics and Astronomy · #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Scientific Research and Discoveries #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9406034
to appear in Proceedings of the XIVth Moriond Astrophysics Meeting. 10 pages, uuencoded, compressed postscript file includes figures (~1 Mb after unpacked)
arxiv created 1994/06/11 · arxiv updated 2009/12/01
The degree of complexity and, to a somewhat lesser degree, realism in simulations has advanced rapidly in the past few years. The simplest approach - modeling a cluster as collisionless dark matter and collisonal, non--radiative gas is now fairly well established. One of the most fruitful results of this approach is the \sl morphology--cosmology connection for X-ray clusters. Simulations have provided the means to make concrete predictions for the X-ray morphologies of clusters in cosmologies with different Ωo, with the result that low Ωo cosmologies fair rather poorly when compared to observations. Another result concerns the accuracy of \xray binding mass estimates. The standard, hydrostatic, isothermal model estimator is found to be accurate to typically better than 50% at radii where the density contrast is between 102 and 103. More complicated approaches, which attempt to explicitly follow galaxy formation within the proto--cluster environment are slowly being realized. The key issue of \sl dynamical biasing of the galaxy population within a cluster is being probed, but conclusive answers are lacking. The dynamics of multi--phase gas, including conversion of cold, dense gas into stars and the feedback therefrom, is the largest obstacle hindering progress. An example demonstrating the state--of--the--art in this area is presented.