1997/11/11 by Evalyn I. Gates, Geza Gyuk, Gilbert P. Holder +1 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/311406
published as Astrophys.J. 500 (1998) L145 · 5 pages + 3 figures
arxiv created 1997/11/11 · openalex publication_date 1998/06/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
One interpretation of the more than dozen microlensing events seen in the direction of the LMC is a halo population of 0.5 M ☉ MACHOs that accounts for about half of the mass of the Galaxy. Such an interpretation is not without its problems, and we show that LMC microlensing can be explained by a combination of dark components of the thick disk and spheroid in a viable and detailed model of the Galaxy. In our models, the total mass within 50 kpc is ~10 11 M ☉ , about 60% of the value based on halo MACHO models, and the estimate for the lens mass is lower, 0.3 M ☉ versus 0.5 M ☉ . The chemical evolution problems associated with the MACHO progenitors are not resolved. However, since the MACHO distribution does not trace the 1/ r 2 dark halo, which extends significantly beyond 50 kpc, the total baryon mass fraction of the Galaxy is reduced considerably, which lessens the problem.