X-Ray Total Mass Estimate for the Nearby Relaxed Cluster A3571
Abstract
We constrain the total mass distribution in the cluster A3571, combining spatially resolved ASCA temperature data with ROSAT imaging data with the assumption that the cluster is in hydrostatic equilibrium. The total mass within r500 (1.7 h-150 Mpc) is M500=7.8+1.4-2.2×1014 h-150 Msolar at 90% confidence, 1.1 times smaller than the isothermal estimate. The Navarro, Frenk, & White ``universal profile'' is a good description of the dark matter density distribution in A3571. The gas density profile is shallower than the dark matter profile, scaling as r-2.1 at large radii, leading to a monotonically increasing gas mass fraction with radius. Within r500 the gas mass fraction reaches a value of fgas=0.19+0.06-0.03 h-3/250 (90% confidence errors). Assuming that this value of fgas is a lower limit for the universal value of the baryon fraction, we estimate the 90% confidence upper limit of the cosmological matter density to be Ωm<0.4.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2000
- DOI:
- 10.1086/308906
- arXiv:
- arXiv:astro-ph/0001162
- Bibcode:
- 2000ApJ...536...73N
- Keywords:
-
- Cosmology: Observations;
- Cosmology: Dark Matter;
- galaxies: clusters: individual (A3571);
- Galaxies: Intergalactic Medium;
- X-Rays: Galaxies;
- Astrophysics
- E-Print:
- 10 pages, 4 figures, accepted by ApJ