Sunyaev-Zel'dovich detection of the galaxy cluster Cl J1449+0856 at z = 1.99: The pressure profile in uv space

RAPHAEL ALEXANDRE SIMON GOBAT, E. Daddi, R. T. Coogan, A. M.C. Le Brun, F. Bournaud, J. B. Melin, D. A. Riechers, M. Sargent, F. Valentino, H. S. Hwang, A. Finoguenov, V. Strazzullo

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We present Atacama Large Millimetre Array and Atacama Compact Array observations of the Sunyaev-Zel'dovich effect in the z  =  2 galaxy cluster Cl J1449+0856, an X-ray-detected progenitor of typical massive clusters in the present day Universe. While in a cleaned but otherwise untouched 92 GHz map of this cluster little to no negative signal is visible, careful subtraction of known sub-millimetre emitters in the uv plane reveals a decrement at 5σ significance. The total signal is -190  ±  36 μJy, with a peak offset by 5″-9″ (∼50 kpc) from both the X-ray centroid and the still-forming brightest cluster galaxy. A comparison of the recovered uv-amplitude profile of the decrement with different pressure models allows us to derive total mass constraints consistent with the ∼6  ×  1013M⊙ estimated from X-ray data. Moreover, we find no strong evidence for a deviation of the pressure profile with respect to local galaxy clusters, although a slight tension at small-to-intermediate spatial scales suggests a flattened central profile, opposite to that seen in a cool core and possibly an AGN-related effect. This analysis of the lowest mass single SZ detection so far illustrates the importance of interferometers when observing the SZ effect in high-redshift clusters, the cores of which cannot be considered quiescent, such that careful subtraction of galaxy emission is necessary.

Original languageEnglish
Article numberA104
JournalAstronomy and Astrophysics
StatePublished - 1 Sep 2019
Externally publishedYes


  • Galaxies: clusters: individual: Cl J1449+0856
  • Galaxies: clusters: intracluster medium


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