Skip to main content Accessibility help
×
Hostname: page-component-848d4c4894-jbqgn Total loading time: 0 Render date: 2024-07-03T13:56:10.495Z Has data issue: false hasContentIssue false

Microlensing towards the Magellanic Clouds: Nature of the lenses and implications on dark matter

Published online by Cambridge University Press:  21 August 2009

Kailash C. Sahu
Affiliation:
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA; ksahu@stsci.edu
Mario Livio
Affiliation:
Space Telescope Science Institute, Baltimore
Get access

Summary

A close scrutiny of the microlensing results towards the Magellanic clouds reveals that the stars within the Magellanic clouds are major contributors as lenses, and the contribution of MACHOs to dark matter is 0 to 5%. The principal results which lead to this conclusion are the following:

  1. (i) Out of the ∼17 events detected so far towards the Magellanic Clouds, the lens location has been securely determined for one binary-lens event through its caustic-crossing timescale. In this case, the lens was found to be within the Magellanic Clouds. Although less certain, lens locations have been determined for three other events and in each of these three events, the lens is most likely within the Magellanic clouds.

  2. (ii) If most of the lenses are MACHOs in the Galactic halo, the timescales would imply that the MACHOs in the direction of the LMC have masses of the order of 0.5 M, and the MACHOs in the direction of the SMC have masses of the order of 2 to 3 M. This is inconsistent with even the most flattened model of the Galaxy. If, on the other hand, they are caused by stars within the Magellanic Clouds, the masses of the stars are of the order of 0.2 M for both the LMC as well as the SMC.

  3. (iii) If 50% of the lenses are in binary systems similar to the stars in the solar neighborhood, ∼10% of the events are expected to show binary characteristics.

  4. […]

Type
Chapter
Information
The Dark Universe
Matter, Energy and Gravity
, pp. 14 - 23
Publisher: Cambridge University Press
Print publication year: 2004

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Save book to Kindle

To save this book to your Kindle, first ensure coreplatform@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×