1994/09/01 by N. W. Evans · 3 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #History and Developments in Astronomy #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/187675
12 pages, Latex
arxiv created 1994/09/01 · openalex publication_date 1994/12/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Microlensing maps -- that is, contours of equal numbers of events per 106 source stars -- are provided for the inner Galaxy under two alternative hypotheses : (1) the bulge is an oblate axisymmetric spheroid or (2) the bulge is a prolate bar. Oblate spheroids yield a total of ∼ 12 events per year per 106 stars at Baade's Window (∼ 15 events if the disk is maximal). The event rate is slightly lower for prolate bars viewed at ∼ 45^∘ and the maps have a characteristic asymmetry between positive and negative longitudes. Prolate bars can yield mild amplifications of the event rate if viewed almost down the long axis. The disk provides the dominant lensing population on the bulge major axis for |ℓ | \gta 6^∘. Measurements of the rate at major axis windows can test for disk dark matter or maximal disk models.