In this Letter we compare the abundance of the member galaxies of arich nearby (z = 0.09) galaxy cluster Abell 2142 with that of halosof comparable virial mass extracted from sets of state-of-the-artnumerical simulations both collisionless at different resolutions andwith the inclusion of baryonic physics in the form of cooling starformation and feedback by active galactic nuclei. We also use twosemi-analytical models to account for the presence of orphan galaxies.The photometric and spectroscopic information taken from the SloanDigital Sky Survey Data Release 12 database allows us to estimate thestellar velocity dispersion of member galaxies of Abell 2142. Thisquantity is used as proxy for the total mass of secure cluster membersand is properly compared with that of subhalos in simulations. We findthat simulated halos have a statistically significant (≳ 7 sigmaconfidence level) smaller amount of massive (circular velocity above 200{km} {{{s}}}^-1) subhalos even before accounting for thepossible incompleteness of observations. These results corroborate thefindings from a recent strong lensing study of the Hubble FrontierFields galaxy cluster MACS J0416 and suggest that the observeddifference is already present at the level of dark matter (DM) subhalosand is not solved by introducing baryonic physics. A deeperunderstanding of this discrepancy between observations and simulationswill provide valuable insights into the impact of the physicalproperties of DM particles and the effect of baryons on the formationand evolution of cosmological structures.
Numerical Simulations Challenged on the Prediction of Massive Subhalo Abundance in Galaxy Clusters: The Case of Abell 2142
Mercurio A;
2016-01-01
Abstract
In this Letter we compare the abundance of the member galaxies of arich nearby (z = 0.09) galaxy cluster Abell 2142 with that of halosof comparable virial mass extracted from sets of state-of-the-artnumerical simulations both collisionless at different resolutions andwith the inclusion of baryonic physics in the form of cooling starformation and feedback by active galactic nuclei. We also use twosemi-analytical models to account for the presence of orphan galaxies.The photometric and spectroscopic information taken from the SloanDigital Sky Survey Data Release 12 database allows us to estimate thestellar velocity dispersion of member galaxies of Abell 2142. Thisquantity is used as proxy for the total mass of secure cluster membersand is properly compared with that of subhalos in simulations. We findthat simulated halos have a statistically significant (≳ 7 sigmaconfidence level) smaller amount of massive (circular velocity above 200{km} {{{s}}}^-1) subhalos even before accounting for thepossible incompleteness of observations. These results corroborate thefindings from a recent strong lensing study of the Hubble FrontierFields galaxy cluster MACS J0416 and suggest that the observeddifference is already present at the level of dark matter (DM) subhalosand is not solved by introducing baryonic physics. A deeperunderstanding of this discrepancy between observations and simulationswill provide valuable insights into the impact of the physicalproperties of DM particles and the effect of baryons on the formationand evolution of cosmological structures.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
