Microlensing Maps for the Galactic Bulge

Abstract

Microlensing maps -- that is, contours of equal numbers of events per $10^6$ 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 $\sim 12$ events per year per $10^6$ stars at Baade's Window ($\sim 15$ events if the disk is maximal). The event rate is slightly lower for prolate bars viewed at $\sim 45^{\circ }$ 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 $|\ell | \gta 6^\circ$. Measurements of the rate at major axis windows can test for disk dark matter or maximal disk models.

12 pages, Latex

Cited by in corpus (16)

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• The MACHO Project: 45 Candidate Microlensing Events from the First Year Galactic Bulge Data
• The MACHO project: Microlensing Optical Depth towards the Galactic Bulge from Difference Image Analysis
• Separation of Stellar Populations by an Evolving Bar: Implications for the Bulge of the Milky Way
• Astrometric Microlensing with the GAIA satellite
• New constraints on a triaxial model of the Galaxy
• A Dynamical Model of the Inner Galaxy
• The So-Called "Bar" in the Large Magellanic Cloud
• Something about the structure of the Galaxy
• Microlensing
• Binary events and extragalactic planets in pixel microlensing
• Microlensing Maps for the Milky Way Galaxy
• A Schwarzschild model of the Galactic bar with initial density from N-body simulations
• Mass distribution in our Galaxy
• Signatures of the Galactic bar on stellar kinematics unveiled by APOGEE
• Blending in Future Space-based Microlensing Surveys