XMM-Newton study of the lensing cluster of galaxies CL 0024+17

We present a detailed gravitational mass measurement based on the XMM-Newton imaging spectroscopy analysis of the lensing cluster of galaxies CL 0024+17 at z=0.395. The emission appears approximately symmetric. However, on the scale of r ∼ 3.3^' some indication of elongation is visible in the northwest-southeast (NW-SE) direction from the hardness ratio map (HRM). Within 3^', we measure a global gas temperature of 3.52 ± 0.17 keV, metallicity of 0.22 ± 0.07, and bolometric luminosity of 2.9 ± 0.1 × 10⁴⁴ h^-2₇₀ erg s^-1. We derive a temperature distribution with an isothermal temperature of 3.9 keV to a radius of 1.5^' and a temperature gradient in the outskirts (1.3^'<r<3^'). Under the assumption of hydrostatic equilibrium, we measure gravitational mass and gas mass fraction to be M₂₀₀=2.0 ± 0.3 × 10¹⁴ h₇₀^-1 M_⊙ and f_gas=0.20 ± 0.03 h^-3/2₇₀ at r₂₀₀=1.05 h^-1₇₀ Mpc using the observed temperature profile. The complex structure in the core region is the key to explaining the discrepancy in gravitational mass determined from XMM-Newton X-ray observations and HST optical lensing measurements.

This work is based on observations made with the XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and the USA (NASA).

Based on observations made with the European Southern Observatory telescopes obtained from the ESO/ST-ECF Science Archive Facility.