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T. Furusho (NASA/GSFC), N.Y. Yamasaki, T. Ohashi (Tokyo Metro. Univ.), K. Matsushita, Y. Ikebe (MPE), T. Tamura (SRON)
We report on a Chandra observation of the nearby(z=0.011), X-ray bright, relaxed cluster Abell 1060. There are two giant elliptical galaxies at the cluster center. However, their optical luminosities are lower than those of typical cD galaxies, and the central cool component of the ICM is a very little. In addition, A1060 shows circularly symmetric X-ray surface brightness, and uniformity in the ICM temperature distribution over the cluster with a temperature of about 3 keV. These unique properties indicate that this cluster is the best target to study of the dark halo structure. The previous ASCA and ROSAT analysis reported the gravitational potential in the central region is described better by the universal dark halo profile proposed by Navarro, Frenk, and White than by a beta model. Exploiting the spatial resolution of the Chandra, we resolve the central region clearly into the elliptial galaxies NGC 3311 and NGC 3309, an extended excess emission at the north-east of NGC 3311, and the ICM. The X-ray spectra of these ellipticals are consistent with emission from the hot ISM (kT~0.7 keV) and LMXBs, and the sizes are a radius of about 5 kpc, which is significantly smaller than in the optial band. The north-east excess emission extends about 20 kpc with a rather high temperature. We find that the X-ray surface brightness distribution is fitted well with a 2-beta model (the ISM of NGC 3311 and the ICM), not with a NFW model. TF is supported by the Japan Society for the Promotion of Science.