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Updated: Aug 2, 2026
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Bringing the Visible Universe into Focus with Robo-AO
Published on: February 12, 2013
Clusters of galaxies: a cosmological probe
1NASA Goddard Space Flight Center, Code 130, Office of Public Affairs, Greenbelt, MD 20771, USA.
Summary
X-ray cluster surveys provide strong constraints on cosmological parameters like Omega and Lambda. Cluster chemical composition, particularly iron abundance, is not universal and contradicts elliptical galaxy gas models.
Area of Science:
- Cosmology
- Astrophysics
- Galaxy Evolution
Background:
- Cosmological parameters are crucial for understanding the universe's evolution.
- X-ray cluster surveys offer a powerful tool for constraining these parameters.
- Previous studies indicated a universal chemical composition in galaxy clusters.
Purpose of the Study:
- To present current and potential constraints on cosmological parameters from X-ray cluster surveys.
- To investigate the chemical composition of galaxy clusters and its implications for dark energy.
- To compare cluster abundances with those in other astronomical objects.
Main Methods:
- Analysis of cosmological parameters derived from X-ray cluster surveys.
- Examination of chemical abundances (Fe, Si, S) in cluster gas using data from Advanced Satellite for Cosmology and Astrophysics and XMM-Newton.
- Comparison of observed abundances with theoretical models and observations of Milky Way Halo stars and Lyman-limit galaxies.
Main Results:
- Strong constraints on Omega, Lambda, sigma(8), and the matter power spectrum are achievable.
- The equation of state of dark energy can be constrained.
- Iron abundance in clusters is correlated with cluster mass and central gas density, not universal.
- Abundances in elliptical galaxy gas are subsolar and not alpha-element rich, contradicting existing models.
Conclusions:
- X-ray cluster surveys are vital for precision cosmology.
- The non-universal chemical composition of clusters challenges current astrophysical models.
- Discrepancies in elliptical galaxy gas abundances necessitate revised models for galaxy evolution.
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