Gravitational Microlensing - A Report on the MACHO Project

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dc.creatorSutherland, Will
dc.date1998-11-11
dc.date.accessioned2026-07-07T11:29:47Z
dc.date.available2026-07-07T11:29:47Z
dc.descriptionThere is abundant evidence that the mass of the Universe is dominated by dark matter of unknown form. The MACHO project is one of several teams searching for the dark matter around our Galaxy in the form of Massive Compact Halo Objects (MACHOs). If a compact object passes very close to the line of sight to a background star, the gravitational deflection of light causes an apparent brightening of the star, i.e. a gravitational `microlensing' event. Such events will be very rare, so millions of stars must be monitored for many years. We describe our search for microlensing using a very large CCD camera on the dedicated 1.27m telescope at Mt. Stromlo, Australia: currently some 14 events have been discovered towards the Large Magellanic Cloud. The lack of short-timescale events excludes planetary mass MACHOs as a major contributor to the dark matter, but the observed long events (durations 1--6 months) suggest that a major fraction may be in fairly massive objects $\sim 0.5 \Msun$. It is currently difficult but not impossible to explain these events by other lens populations; we discuss some prospects for clarifying the nature of the lenses.
dc.descriptionRevTex, 20 pages incl. 11 Postscript figures. Rev. Mod. Phys. 'Colloquium' article, to appear Jan. 1999
dc.identifierhttps://arxiv.org/abs/astro-ph/9811185
dc.identifierhttp://arxiv.org/abs/astro-ph/9811185
dc.identifierRev.Mod.Phys.71:421-434,1999
dc.identifierdoi:10.1103/RevModPhys.71.421
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/196821
dc.subjectAstrophysics
dc.subjectGeneral Relativity and Quantum Cosmology
dc.subjectHigh Energy Physics - Phenomenology
dc.titleGravitational Microlensing - A Report on the MACHO Project
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