The baryon fraction in the perseus cluster: Results from spartan

R. G. Cruddace*, M. P. Kowalski, G. G. Fritz, W. A. Snyder, E. E. Fenimore, M. P. Ulmer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Spatially and spectrally resolved X-ray observations of the Perseus cluster in the 1-10 keV band were made by the Spartan 1 instrument. Analysis of the data reveals that the dark matter comprises 60% of the total mass and is concentrated toward the cluster center. This concentration may be caused by a baryonic component of the dark matter, consisting of cluster gas which has cooled. The average luminous baryon fraction within the cluster is consistent with big bang nucleosynthesis only if the cosmic mass density lies in the range 0.12 < Ω < 0.26 (H0 = 50 km s-1 Mpc-1). The total mass derived from the X-ray data is 40% of that obtained from analysis of the galaxy spatial and velocity distributions.

Original languageEnglish (US)
Pages (from-to)479-488
Number of pages10
JournalAstrophysical Journal
Issue number2 PART I
StatePublished - 1997


  • Dark matter
  • Galaxies: clusters: individual (Perseus)
  • X-rays: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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