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M. Loewenstein, R. F. Mushotzky (NASA/GSFC)
We utilize a combination of Chandra X-ray imaging and imaging-spectroscopy, and Newton-XMM imaging-spectroscopy, of the hot gas in NGC 4636 to constrain the dark matter distribution in this elliptical galaxy on scales ranging from 100 pc to 30 kpc. We find that dark matter comprises a significant fraction of the total mass well-inside the optical half-light radius: unlike previously studied types of galaxies, dark matter is not less concentrated than expected based on cold dark matter numerical simulations . We discuss the implications of our findings on suggestions that dark matter may be self-interacting and/or altered during the galaxy formation process by dynamical coupling to other mass components.
The author(s) of this abstract have provided an email address for comments about the abstract: loew@larmes.gsfc.nasa.gov