LoCuSS: Calibrating mass-observable scaling relations for cluster cosmology with Subaru weak-lensing observations

N. Okabe, Y. Y. Zhang, A. Finoguenov, M. Takada, G. P. Smith, K. Umetsu, T. Futamase

Research output: Contribution to journalArticlepeer-review

90 Citations (Scopus)


We present a joint weak-lensing/X-ray study of galaxy cluster mass-observable scaling relations motivated by the critical importance of accurate calibration of mass proxies for future X-ray missions, including eROSITA. We use a sample of 12 clusters at z ≃ 0.2 that we have observed with Subaru and XMM-Newton to construct relationships between the weak-lensing mass (M) and three X-ray observables, gas temperature (T), gas mass (M gas), and quasiintegrated gas pressure (YX), at overdensities of Δ = 2500, 1000, and 500 with respect to the critical density.We find that Mgas at Δ ≤ 1000 appears to be the most promising mass proxy of the three because it has the lowest intrinsic scatter in mass at a fixed observable, σlnM ≃ 0.1, independent of the cluster dynamical state. The scatter in mass at fixed T and YX is a factor of ∼2-3 larger than at fixedMgas, which are indicative of the structural segregation that we find in theM-T andM-YX relationships. Undisturbed clusters are found to be ∼40% and ∼20% more massive than disturbed clusters at fixed T and YX, respectively, at∼2σ significance. In particular, A 1914-a well-known merging cluster-significantly increases the scatter and lowers the normalization of the relation for disturbed clusters. We also investigated the covariance between the intrinsic scatter in M-Mgas and M-T relations, finding that they are positively correlated. This contradicts the adaptive mesh refinement simulations that motivated the idea that YX may be a low-scatter mass proxy, and agrees with more recent smoothed particle hydrodynamic simulations based on the Millennium Simulation. We also propose a method to identify a robust mass proxy based on principal component analysis. The statistical precision of our results is limited by the small sample size and the presence of the extreme merging cluster in our sample.We therefore look forward to studying a larger, more complete sample in the future.

Original languageEnglish
Pages (from-to)875-885
Number of pages11
JournalAstrophysical Journal
Issue number1
Publication statusPublished - 2010 Sep 20


  • Cosmology: observations
  • Dark matter
  • Galaxies: clusters: general
  • Gravitational lensing: weak
  • X-rays: galaxies: clusters

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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