Nature versus nurture: the curved spine of the galaxy cluster X-ray luminosity–temperature relation

• Published in: Monthly notices of the Royal Astronomical Society Vol. 386; no. 4; pp. 2015 - 2021
• Main Authors: Hartley, W. G., Gazzola, L., Pearce, F. R., Kay, S. T., Thomas, P. A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-06-2008; Blackwell Science; Oxford University Press
• Subjects: Astronomy; Astrophysics; cosmology: theory; Earth, ocean, space; Exact sciences and technology; Fluid dynamics; hydrodynamics; methods: numerical; Simulation; Stars & galaxies; X-rays; methods: numerical; hydrodynamics; cosmology: theory; Galaxy clusters; Digital simulation; Luminosity; Hydrodynamic model; Cosmology; Numerical method
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2008.13127.x

The physical processes that define the spine of the galaxy cluster X-ray luminosity–temperature (L–T) relation are investigated using a large hydrodynamical simulation of the universe. This simulation models the same volume and phases as the millennium simulation and has a linear extent of 500 h−1Mpc. We demonstrate that mergers typically boost a cluster along but also slightly below the L–T relation. Due to this boost, we expect that all of the very brightest clusters will be near the peak of a merger. Objects from near the top of the L–T relation tend to have assembled much of their mass earlier than an average halo of similar final mass. Conversely, objects from the bottom of the relation are often experiencing an ongoing or recent merger.