Quintessential halos around galaxies

The nature of the dark matter that binds galaxies remains an open question.The favored candidate has been so far the neutralino. This massive species withevanescent interactions is now in difficulty. It would actually collapse indense clumps and would therefore play havoc with the matter it is supposed toshepherd. We focus here on a massive and non-interacting charged scalar fieldas an alternate option to the astronomical missing mass. We investigate theclassical solutions that describe the Bose condensate of such a field ingravitational interaction with matter. This simplistic model accounts quitewell for the dark matter inside low-luminosity spirals whereas the agreementlessens for the brightest objects where baryons dominate. A scalar mass m=0.4to 1.6 10^{-23} eV is derived when both high and low-luminosity spirals arefitted at the same time. Comparison with astronomical observations is madequantitative through a chi-squared analysis. We conclude that scalar fieldsoffer a promising direction worth being explored.Comment: 16 pages, 5 figure