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The effect of non--gravitational gas heating in groups and clusters of galaxies

S. Borgani·F. Governato·J. Wadsley·N. Menci·P. Tozzi·T. Quinn·J. Stadel·G. Lake
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Abstract

We present a set of gas-dynamical simulations of galaxy groups and clusters aimed at exploring the effect of non-gravitational heating. We use GASOLINE, a parallel Tree+SPH code, to simulate the formation of four cosmic halos with temperature 0.5<T<8 keV. Non-gravitational heating is implemented in two different ways: (1) by imposing a minimum entropy floor at a given redshift, 1<z<5; (2) by gradually heating gas, proportionally to the SN rate expected from semi-analytical modeling of galaxy formation. Our main results are the following. (a) An extra heating energy of about 1 keV per gas particle is required to reproduce the observed Lx-T relation, independent of whether it is provided so as to create an entropy floor of 50-100 keV cm^2, or is modulated in redshift; our SN feedback recipe provides only 1/3 keV/part. (b) The M-T relation is almost unaffected by non-gravitational heating and follows the M T^{3/2} scaling, with a normalization ~40% higher than observed, independent of the heating scheme. The inclusion of cooling in a run of a small group has the effects of increasing T_ew by ~30%, possibly reconciling simulated and observed M-T relations, and of decreasing Lx by ~40%. In spite of the inclusion of SN feedback energy, almost 40% of the gas becomes cold, in excess of current observational estimates. (abridged)

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S. Borgani, F. Governato, J. Wadsley, N. Menci, P. Tozzi, T. Quinn, J. Stadel, G. Lake. 2002-05-27. The effect of non--gravitational gas heating in groups and clusters of galaxies. https://doi.org/10.1046/j.1365-8711.2002.05746.x

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