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Register a new userThe evolution of the luminosity-temperature-mass relations of hot gas in Chandra clusters at 0.4 < z < 1.4
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We analyzed the luminosity-temperature-mass of gas (L_{X} - T - M_{g}) relation for sample of galaxy clusters that have been observed by the Chandra satellite. We used 21 high-redshift clusters (0.4 < z < 1.4). We assumed a power-law relation between the X-ray luminosity of galaxy clusters and its temperature and redshift L_{X} ~ (1+z)^{A_{L_{X}T}}T^{beta_{L_{X}T}}. We obtained that for an Omega_{m} = 0.27 and Lambda = 0.73 universe, A_{L_{X}T} = 1.50 +/- 0.23, beta_{L_{X}T} = 2.55 +/- 0.07 (for 68% confidence level). Then, we found the evolution of M_{g} - T relation is small. We assumed a power-law relation in the form M_{g} ~ (1+z)^{A_{M_{g}T}}T^{beta_{M_{g}T}} also, and we obtained A_{M_{g}T} = -0.58 +/- 0.13 and beta_{M_{g}T} = 1.77 +/- 0.16. We also obtained the evolution in M_{g} - L_{X} relation, we can conclude that such relation has strong evolution for our cosmological parameters. We used M_{g} ~ (1+z)^{A_{M_{g}L_{X}}}L^{beta_{M_{g}L_{X}}} equation for assuming this relation and we found A_{M_{g}L_{X}} ~ -1.86 +/- 0.34 and beta_{M_{g}L_{X}} = 0.73 +/- 0.15 for Omega_{m} = 0.27 and Lambda = 0.73 universe. In overal, the clusters on big redshifts have much stronger evolution between correlations of luminosity, temperature and mass, then such correlations for clusters at small redshifts. We can conclude that such strong evolution in L_{X} - T - M_{g} correlations indicate that in the past the clusters have bigger temperature and higher luminosity.
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Galaxy clusters are the most recent products of hierarchical accretion over cosmological scales. The gas accreted from the cosmic field is thermalized inside the cluster halo. Gas entropy and pressure are expected to have a self-similar behaviour with their radial distribution following a power law and a generalized Navarro-Frenk-White profile, respectively. This has been shown also in many different hydrodynamical simulations. We derive the spatially-resolved thermodynamical properties of 47 X-ray galaxy clusters observed with Chandra in the redshift range 0.4 < z < 1.2, the largest sample investigated so far in this redshift range with X-rays spectroscopy, with a particular care in reconstructing the gas entropy and pressure radial profiles. We search for deviation from the self-similar behaviour and look for possible evolution with redshift. The entropy and pressure profiles lie very close to the baseline prediction from gravitational structure formation. We show that these profiles deviate from the baseline prediction as function of redshift, in particular at z > 0.75, where, in the central regions, we observe higher values of the entropy (by a factor of 2.2) and systematically lower estimates (by a factor of 2.5) of the pressure. The effective polytropic index, which retains informations about the thermal distribution of the gas, shows a slight linear positive evolution with the redshift and the concentration of the dark matter distribution. A prevalence of non-cool-core, disturbed systems, as we observe at higher redshifts, can explain such behaviours.
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