Astronomy and Astrophysics, volume 369, 459-466 (2001/4-2)
Temperature and total mass profiles of the A3571 cluster of galaxies.
NEVALAINEN J., KAASTRA J., PARMAR A.N., MARKEVITCH M., OOSTERBROEK T., COLAFRANCESCO S. and MAZZOTTA P.
Abstract (from CDS):
We present BeppoSAX results of a spatially resolved spectral analysis of A3571, a relaxed nearby cluster of galaxies. In the central 2' (130h50–1kpc) radius the metal abundance is 0.49±0.08 solar and the absorption (1.13±0.28)x1021atom/cm2, whereas elsewhere within an 8' (520h50–1kpc) radius the abundance is 0.32±0.05 solar and the absorption consistent with the galactic value of 4.4x1020atom/cm2. The significant central metal abundance enhancement is consistent with the supernova enrichment scenario. The excess absorption may be attributed to the cooling flow, whose mass flow rate is 80±40M☉/yr from our spectral fit. The BeppoSAX and ASCA radial temperature profiles agree over the entire overlapping radial range r<25'=1.6h50–1Mpc. The combined BeppoSAX and ASCA temperature profile exhibits a constant value out to a radius of ∼10' (650h50–1kpc) and a significant decrease (T∝r–0.55, corresponding to γ=1.28) at larger radii. These temperature data are used to derive the total mass profile. The best fit NFW dark matter density model results in a temperature profile that is not convectively stable, but the model is acceptable within the uncertainties of the data. The temperature profile is acceptably modeled with a ``core'' model for the dark matter density, consisting of a core radius with a constant slope at larger radii. With this model the total mass and formal 90% confidence errors within the virial radius r178 (2.5h50–1Mpc) are 9.1+3.6–1.5x1014h50–1M☉, by a factor of 1.4 smaller than the isothermal value. The gas mass fraction increases with radius, reaching fgas(r178)=0.26+0.05–0.10xh50–3/2. Assuming that the measured gas mass fraction is the lower limit to the primordial baryonic fraction gives Ωm<0.4 at 90% confidence.
cosmology: observations - dark matter - X-rays: clusters of galaxies