Quasar Microlensing: when compact masses mimic smooth matter

Abstract

The magnification induced by gravitational microlensing is sensitive to the size of a source relative to the Einstein radius, the natural microlensing scale length. This paper investigates the effect of source size in the case where the microlensing masses are distributed with a bimodal mass function, with solar mass stars representing the normal stellar masses, and smaller masses (down to $8.5\times 10^{-5}$M${}_{\odot }$) representing a dark matter component. It is found that there exists a critical regime where the dark matter is initially seen as individual compact masses, but with an increasing source size the compact dark matter acts as a smooth mass component. This study reveals that interpretation of microlensing light curves, especially claims of small mass dark matter lenses embedded in an overall stellar population, must consider the important influence of the size of the source.

6 pages, to appear in ApJ. As ever, quality of figures reduced

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Cited by in corpus (11)

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• A comparison of the strong lensing properties of the Sersic and the NFW profiles
• Smooth matter and source size in microlensing simulations of gravitationally lensed quasars
• Gravitational Microlensing: A parallel, large-data implementation
• Q2237+0305 source structure and dimensions from light curves simulation
• Gravitational Nanolensing from Subsolar Mass Dark Matter Halos
• High-redshift microlensing and the spatial distribution of dark matter in the form of MACHOs
• Probing planetary mass dark matter in galaxies: gravitational nanolensing of multiply imaged quasars
• The Water Maser in MG 0414+0534: The Influence of Gravitational Microlensing