X-ray C-M relation: theory and observation. (arXiv:1301.7476v1 [astro-ph.CO])

X-ray C-M relation: theory and observation. (arXiv:1301.7476v1 [astro-ph.CO]):
[Abridged] Since fifteen years, the concentration-mass relation has been
investigated diffusely in theoretical studies. On the other hand, only recently
this relation has been derived from X-ray observations. When that happened, the
results caused a certain level of concern: the X-ray normalizations and slopes
were found significantly dissimilar from those predicted by theory.

By analyzing a total of 52 objects, simulated each time with different
physical recipes for the baryonic component, as well as 60 synthetic X-ray
images, we aim at determining if these discrepancies are real or artificial. In
particular, we investigate how the simulated concentration-mass relation
depends i) on the radial range used to derive the concentration, ii) on the
presence of baryons in the simulations, and on the prescription used to
reproduce the gas. Finally, we evaluate iii) how the results differ when
adopting an X-ray approach for the analysis and iv) how the selection functions
based on X-ray luminosity, temperature, and SZ-signal can impact the results.
All effects studied go in the direction of explaining the discrepancy between
observations and simulations, but they contribute at different levels: while
the fitting radial range and the baryonic component play only a minor role, the
X-ray approach and selection function have profound repercussion on the
results.


RKS Note: Important paper comparing simulated clusters with observed ones, especially in regard to extracting cosmological parameters.