Cosmological hydrodynamical simulations of galaxy clusters: X-ray scaling relations and their evolution

STEINBORN, L K; GRANATO, G L; BORGANI, S; BIFFI, V; RASIA, E; RAGONE-FIGUEROA, C; GASPARI, M; BECK, A M; PLANELLES, S; TRUONG, N; MURANTE, G; DOLAG, K; FABJAN, D; MAZZOTTA, P

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2018 vol. 474 p. 4089 - 4111

0035-8711

We analyse cosmological hydrodynamical simulations of galaxy clusters to study the X-rayscaling relations between total masses and observable quantities such as X-ray luminosity, gasmass, X-ray temperature, and Y X . Three sets of simulations are performed with an improvedversion of the smoothed particle hydrodynamics GADGET -3 code. These consider the following:non-radiative gas, star formation and stellar feedback, and the addition of feedback by activegalactic nuclei (AGN). We select clusters with M 500 > 10 14 M E(z) −1 , mimicking the typicalselection of Sunyaev?Zeldovich samples. This permits to have a mass range large enoughto enable robust fitting of the relations even at z ∼ 2. The results of the analysis show ageneral agreement with observations. The values of the slope of the mass?gas mass and mass?temperature relations at z = 2 are 10 per cent lower with respect to z = 0 due to the applied massselection, in the former case, and to the effect of early merger in the latter. We investigate theimpact of the slope variation on the study of the evolution of the normalization. We concludethat cosmological studies through scaling relations should be limited to the redshift rangez = 0?1, where we find that the slope, the scatter, and the covariance matrix of the relationsare stable. The scaling between mass and Y X is confirmed to be the most robust relation, beingalmost independent of the gas physics. At higher redshifts, the scaling relations are sensitiveto the inclusion of AGNs which influences low-mass systems. The detailed study of theseobjects will be crucial to evaluate the AGN effect on the ICM.