Using Globular Clusters to Test Newton's Law of Gravity

Scarpa, R.; Marconi, G.; Gilmozzi, R.
Bibliographical reference

International Astronomical Union Symposium no. 220, held 21 - 25 July, 2003 in Sydney, Australia. Eds: S. D. Ryder, D. J. Pisano, M. A. Walker, and K. C. Freeman. San Francisco: Astronomical Society of the Pacific., p.215

Advertised on:
7
2004
Number of authors
3
IAC number of authors
0
Citations
9
Refereed citations
8
Description
New measurements of the velocity dispersion of the globular cluster ω Centauri allow us to trace its gravitational potential down to an acceleration of 8×10-9 cm s-2. It is found that the dispersion profile remains flat well inside the tidal radius as soon as the acceleration of gravity approaches a_0, a result that finds its simplest explanation within the context of MOND. A similar behaviour is observed in the globular cluster M15 showing this is not a peculiar feature of ω Centauri. This result is surprising and suggestive of a failure of Newton's law at low accelerations.