English

What Could the Machos Be?

Astrophysics 2009-10-31 v1

Abstract

If the Universe has a significant baryonic dark component in the form of compact objects in galaxy halos (machos), then there is a minute chance (about 10710^{-7}) that one of the Galactic machos passes sufficiently close to our line of sight to a star out of some 10710^7 monitored stars in the Magellanic Clouds (MCs) that it brightens by more than 0.3 magnitude due to gravitational focusing. After a brief discussion of the current controversy over the interpretation of the observed events, i.e., whether the lensing is caused by halo white dwarfs or machos in general or by stars in various observed or hypothesized structures of the Clouds and the Galaxy, I propose a few observations to put ideas of the pro-macho camp and the pro-star camp to test. In particular, I propose a radial velocity survey towards the MCs.

Keywords

Cite

@article{arxiv.astro-ph/9902179,
  title  = {What Could the Machos Be?},
  author = {HongSheng Zhao},
  journal= {arXiv preprint arXiv:astro-ph/9902179},
  year   = {2009}
}

Comments

7 pages including 6 Postcsript files for two figures. Invited talk at COSMO-98, November 1998, Asilomar. To appear in Particle Physics and the Early Universe, AIP Proc. ed. David Caldwell