The Sunyaev-Zeldovich effect in Abell 370

Laura Grego, John E. Carlstrom, Marshall K. Joy, Erik D. Reese, Gilbert P. Holder, Sandeep Patel, Asantha R. Cooray, William L. Holzapfel

Research output: Contribution to journalArticlepeer-review


We present interferometric measurements of the Sunyaev-Zeldovich (SZ) effect toward the galaxy cluster Abell 370. These measurements, which directly probe the pressure of the cluster's gas, show the gas distribution to be strongly aspherical, as do the X-ray and gravitational lensing observations. We calculate the cluster's gas mass fraction in two ways. We first compare the gas mass derived from the SZ measurements to the lensing-derived gravitational mass near the critical lensing radius. We also calculate the gas mass fraction from the SZ data by deprojecting the three-dimensional gas density distribution and deriving the total mass under the assumption that the gas is in hydrostatic equilibrium (HSE). We test the assumptions in the HSE method by comparing the total cluster mass implied by the two methods and find that they agree within the errors of the measurement. We discuss the possible systematic errors in the gas mass fraction measurement and the constraints it places on the matter density parameter, ΩM.

Original languageEnglish (US)
Pages (from-to)39-51
Number of pages13
JournalAstrophysical Journal
Issue number1 PART 1
StatePublished - Aug 10 2000
Externally publishedYes


  • Cosmic microwave background
  • Cosmology: observations
  • Galaxies: clusters: individual (Abell 370)
  • Techniques: interferometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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