Galaxy clusters at z~1 imaged by ALMA with the Sunyaev-Zel'dovich effect

T. Kitayama, S. Ueda, N. Okabe, T. Akahori, M. Hilton, J. P. Hughes, Y. Ichinohe, K. Kohno, E. Komatsu, Y. -T. Lin, H. Miyatake, M. Oguri, C. Sifón, S. Takakuwa, M. Takizawa, T. Tsutsumi, J. van Marrewijk, E. J. Wollack

Submitted on 20 September 2022


We present high angular-resolution measurements of the thermal Sunyaev-Zel'dovich effect (SZE) toward two galaxy clusters, RCS J2319+0038 at z=0.9 and HSC J0947-0119 at z=1.1, by the Atacama Large Millimeter/submillimeter Array (ALMA) in Band 3. They are supplemented with available Chandra X-ray data, optical data taken by Hyper Suprime-Cam on Subaru, and millimeter-wave SZE data from the Atacama Cosmology Telescope. Taking into account departures from spherical symmetry, we have reconstructed non-parametrically the inner pressure profile of two clusters as well as electron temperature and density profiles for RCS J2319+0038. This is one of the first such measurements for an individual cluster at z0.9. We find that the inner pressure profile of both clusters is much shallower than that of local cool-core clusters. Our results consistently suggest that RCS J2319+0038 hosts a weak cool core, where radiative cooling is less significant than in local cool cores. On the other hand, HSC J0947-0119 exhibits an even shallower pressure profile than RCS J2319+0038 and is more likely a non-cool-core cluster. The SZE centroid position is offset by more than 140 h701kpc from the peaks of galaxy distribution in HSC J0947-0119, suggesting a stronger influence of mergers in this cluster. We conclude that these distant clusters are at a very early stage of developing the cool cores typically found in clusters at lower redshifts.


Comment: 26 pages, 13 figures, 8 tables, submitted to PASJ

Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics; Astrophysics - Astrophysics of Galaxies