THE MASS OF ABELL-1060 AND AWM-7 FROM SPATIALLY-RESOLVED X-RAY SPECTROSCOPY - VARIATIONS IN BARYON FRACTION

Using X-ray temperature and surface brightness profiles of the hot int racluster medium (ICM) derived from ACA (Astro-D) and ROSAT observatio ns, we place constraints on the dark matter (DM) and baryon fraction d istributions in the poor clusters Abell 1060 (A1060) and AWM 7. Althou gh their total mass distributions are similar, AWM 7 has twice the bar yon fraction of A1060 in the best-fit models. The functional form of t he DM distribution is ill determined; however, mass models where the b aryon fractions in A1060 and AWM 7 significantly overlap are excluded. Such variations in baryon fraction are not predicted by standard mode ls and imply that some mechanism in addition to gravity plays a major role in organizing matter on cluster scales.