%0 Generic %1 schaller2014effect %A Schaller, Matthieu %A Frenk, Carlos S. %A Bower, Richard G. %A Theuns, Tom %A Trayford, James %A Crain, Robert A. %A Furlong, Michelle %A Schaye, Joop %A Vecchia, Claudio Dalla %A McCarthy, I. G. %D 2014 %K baryons dark matter profile %T The effect of baryons on the inner density profiles of rich clusters %U http://arxiv.org/abs/1409.8297 %X We use the "Evolution and assembly of galaxies and their environment" (EAGLE) cosmological simulation to investigate the effect of baryons on the density profiles of rich galaxy clusters. We focus on the six most massive EAGLE clusters ($M_200 > 10^14M_ødot$) which can be compared with a recent analysis of seven real clusters by Newman et al. The central brightest cluster galaxies (BCGs) in EAGLE have steep stellar density profiles, $\rho_*(r) r^-3$. Stars dominate the mass density for $r < 10~kpc$, and, as a result, the total mass density profiles are steeper than the Navarro-Frenk-White (NFW) profile. However, the dark matter halo itself closely follows the NFW form at all resolved radii ($r\gtrsim3.0~kpc$). The BCGs have similar surface brightness and line-of-sight velocity dispersion profiles as the BCGs observed by Newmanet al. The central slopes of the total mass profiles are also consistent with the observed clusters. However, after subtracting the contribution of the stars to the central density, Newman et al. find significantly shallower slopes than NFW, in contradiction with the EAGLE results. We discuss possible reasons for this discrepancy, such as differences in the mass of the simulated and observed clusters or orientation biases in the observed sample. We conclude that an inconsistency between the kinematical model adopted by Newman et al. for their BCGs, which assumes isotropic stellar orbits, and the kinematical structure of the EAGLE BCGs, in which the orbital stellar anisotropy varies with radius and tends to be radially biased, could explain at least part of the discrepancy.

@misc{schaller2014effect, abstract = {We use the "Evolution and assembly of galaxies and their environment" (EAGLE) cosmological simulation to investigate the effect of baryons on the density profiles of rich galaxy clusters. We focus on the six most massive EAGLE clusters ($M_{200} > 10^{14}M_\odot$) which can be compared with a recent analysis of seven real clusters by Newman et al. The central brightest cluster galaxies (BCGs) in EAGLE have steep stellar density profiles, $\rho_*(r) \propto r^{-3}$. Stars dominate the mass density for $r < 10~{\rm kpc}$, and, as a result, the total mass density profiles are steeper than the Navarro-Frenk-White (NFW) profile. However, the dark matter halo itself closely follows the NFW form at all resolved radii ($r\gtrsim3.0~{\rm kpc}$). The \eagle BCGs have similar surface brightness and line-of-sight velocity dispersion profiles as the BCGs observed by Newmanet al. The central slopes of the total mass profiles are also consistent with the observed clusters. However, after subtracting the contribution of the stars to the central density, Newman et al. find significantly shallower slopes than NFW, in contradiction with the EAGLE results. We discuss possible reasons for this discrepancy, such as differences in the mass of the simulated and observed clusters or orientation biases in the observed sample. We conclude that an inconsistency between the kinematical model adopted by Newman et al. for their BCGs, which assumes isotropic stellar orbits, and the kinematical structure of the EAGLE BCGs, in which the orbital stellar anisotropy varies with radius and tends to be radially biased, could explain at least part of the discrepancy.}, added-at = {2014-10-01T09:54:41.000+0200}, author = {Schaller, Matthieu and Frenk, Carlos S. and Bower, Richard G. and Theuns, Tom and Trayford, James and Crain, Robert A. and Furlong, Michelle and Schaye, Joop and Vecchia, Claudio Dalla and McCarthy, I. G.}, biburl = {https://www.bibsonomy.org/bibtex/2c8296c9889dba2c3568c3ae09d1c98fb/miki}, description = {[1409.8297] The effect of baryons on the inner density profiles of rich clusters}, interhash = {3e4dc55d88be42aeb94f504e6fd3eeb3}, intrahash = {c8296c9889dba2c3568c3ae09d1c98fb}, keywords = {baryons dark matter profile}, note = {cite arxiv:1409.8297Comment: 13 pages, 7 figures, submitted to MNRAS}, timestamp = {2014-10-01T09:54:41.000+0200}, title = {The effect of baryons on the inner density profiles of rich clusters}, url = {http://arxiv.org/abs/1409.8297}, year = 2014 }