2000/06/30 by Roman R. Rafikov, R. R. Rafikov, Bruce T. Draine +1 · 3 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Dark matter #Formalism (music) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gravitational lens #Gravitational microlensing #Mass distribution #Population #Solar mass #Stars #astro-ph
paper · pdf · doi:10.1086/318355
published as Astrophys.J. 547 (2001) 207-216 · 36 pages, 9 figures, 1 table, typos corrected, minor changes
arxiv created 2000/12/13 · openalex publication_date 2001/01/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
It has been proposed that the Galaxy might contain a population of cold clouds in numbers sufficient to account for a substantial fraction of the total mass of the Galaxy. These clouds would have masses of ~10 -3 M ☉ and sizes ~10 AU. Here we consider the lensing effects of such clouds on the light from background stars. We develop a semianalytical formalism for calculating the magnification event rate produced by such gaseous lensing, taking into account the spatial distribution of the dark matter in the Galaxy, the velocity distribution of the lensing clouds and source stars, and motion of the observer. Event rates are calculated for the case of gaseous lensing of stars in the Large Magellanic Cloud, and results are directly compared with the results of the search for gravitational microlensing events undertaken by the MACHO collaboration. The MACHO experiment strongly constrains the properties of the proposed molecular clouds, but does not completely rule them out. Future monitoring programs will either detect or more strongly constrain this proposed population.