the macho project - rutgers physics & astronomysaurabh/690/feb14...the macho project...
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![Page 1: The MACHO Project - Rutgers Physics & Astronomysaurabh/690/Feb14...The MACHO Project Microlensing Results from 5.7 Years of LMC Observations C. Alcock et. al. Main Results •Dark](https://reader035.vdocuments.site/reader035/viewer/2022070917/5fb755a11e333a3472296285/html5/thumbnails/1.jpg)
The MACHOProject
Microlensing Results from 5.7Years of LMC Observations
C. Alcock et. al.
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Main Results
• Dark Matter Halo of our galaxy is notcomposed entirely of MACHOs.
• Constraint on contribution of MACHOs tothe halo of our galaxy between 8% – 50%.
• Constraint on the Mass of MACHOsbetween 0.15 MO – 1 MO.
![Page 3: The MACHO Project - Rutgers Physics & Astronomysaurabh/690/Feb14...The MACHO Project Microlensing Results from 5.7 Years of LMC Observations C. Alcock et. al. Main Results •Dark](https://reader035.vdocuments.site/reader035/viewer/2022070917/5fb755a11e333a3472296285/html5/thumbnails/3.jpg)
Gravitational Microlensing
![Page 4: The MACHO Project - Rutgers Physics & Astronomysaurabh/690/Feb14...The MACHO Project Microlensing Results from 5.7 Years of LMC Observations C. Alcock et. al. Main Results •Dark](https://reader035.vdocuments.site/reader035/viewer/2022070917/5fb755a11e333a3472296285/html5/thumbnails/4.jpg)
Gravitational Microlensing
• Observations of 11.9 million stars in the LMC over a period of 5.7 years.• Number of microlensing events: 13-17
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Event Selection Criteria
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Sources of Uncertainty
• Main source of error is from uncertainty inmodels of the Milky Way and LMC.
• Criteria Set B is has low S/N• Crowding• Supernova• Cosmic Rays• Variable Stars which produce background
micolensing (bumpers)
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Interpretation
• One explanation is that MACHOscomprise 20% of Milky Way halo mass.
• Total implied mass of MACHOs within 50kpc, of 9x1010 MO.
• Another explanation is that the LMC halodominates microlensing, and there are noMACHOs in our galaxy.
• Some MACHOs may be white dwarf stars.