Substructures Revealed by the Sunyaev–Zel’dovich Effect at 150 GHz in a High-Resolution Map of RX J1347$-$1145

Abstract

Abstract We report on mapping observations toward the region of the most luminous X-ray cluster, RX J1347$-$1145 ($ z=0.45$), through the Sunyaev–Zel’dovich effect at 21 GHz and 150 GHz with the Nobeyama 45-m telescope. While a low angular resolution image at 21 GHz (beam-size $ \sigma_\mathrm{FWHM}$ of 76$ {}^{\mathrm{\prime\prime}}$) shows a consistent feature with the ROSAT/HRI X-ray image, a higher angular resolution image ($ \sigma_\mathrm{FWHM} =13^{\prime\prime}$) at 150 GHz reveals complex morphological structures of the cluster region, which cannot be simply described by the spherical isothermal $ \beta$-model. If such inhomogeneous morphological features prove to be generic for high-redshift clusters, distance measurements to the clusters based on their Sunyaev–Zel’dovich data with low angular resolution imaging should be interpreted with caution.