MACHO project 2nd year LMC microlensing results and dark matter implications

PDF Version Also Available for Download.

Description

The MACHO Project is searching for galactic dark matter in the form of massive compact halo objects (Machos). Millions of stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge are photometrically monitored in an attempt to detect rare gravitational microlensing events caused by otherwise invisible Machos. Analysis of two years of photometry on 8.5 million stars in the LMC reveals 8 candidate microlensing events, far more than the one event expected from lensing by low-mass stars in known galactic populations. Five these eight events we estimate the optical depth towards the LMC from events with ... continued below

Physical Description

13 p.

Creation Information

Alcock, C.; Allsman, R. A. & Alves, D. February 1996.

Context

This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. It has been viewed 12 times . More information about this article can be viewed below.

Who

People and organizations associated with either the creation of this article or its content.

Sponsor

Publisher

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

Contact Us

What

Descriptive information to help identify this article. Follow the links below to find similar items on the Digital Library.

Description

The MACHO Project is searching for galactic dark matter in the form of massive compact halo objects (Machos). Millions of stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge are photometrically monitored in an attempt to detect rare gravitational microlensing events caused by otherwise invisible Machos. Analysis of two years of photometry on 8.5 million stars in the LMC reveals 8 candidate microlensing events, far more than the one event expected from lensing by low-mass stars in known galactic populations. Five these eight events we estimate the optical depth towards the LMC from events with 2 < i < 200 days to be r2 280 about 2.9+1 4/-0.8 X 10-7. This exceeds the optical depth of 0.5 x 10-7 expected for known stars and is to be compared with an optical depth of 4.7 X 10-7 predicted for a `standard` halo composed entirely of Machos. The total mass in this lensing population is 2 +1.2/-0.7 x 10+11 Mo (within 50 kpc from the Galactic center). Event timescales yield a most probable Macho Mass of 0.5 +0.3/-0.2 Mo, although this value is quite model dependent. -0.2

Physical Description

13 p.

Notes

OSTI as DE98050247

Other: FDE: PDF; PL:

Subjects

Source

  • 2. international symposium on sources and detection of dark matter in the universe, Santa Monica, CA (United States), 14-16 Feb 1996

Language

Item Type

Identifier

Unique identifying numbers for this article in the Digital Library or other systems.

  • Other: DE98050247
  • Report No.: UCRL-JC--127203
  • Report No.: CONF-960259--
  • Grant Number: W-7405-ENG-48
  • Office of Scientific & Technical Information Report Number: 644515
  • Archival Resource Key: ark:/67531/metadc696721

Collections

This article is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

What responsibilities do I have when using this article?

When

Dates and time periods associated with this article.

Creation Date

  • February 1996

Added to The UNT Digital Library

  • Aug. 14, 2015, 8:43 a.m.

Description Last Updated

  • April 10, 2017, 1:29 p.m.

Usage Statistics

When was this article last used?

Yesterday: 0
Past 30 days: 3
Total Uses: 12

Interact With This Article

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

Citations, Rights, Re-Use

Alcock, C.; Allsman, R. A. & Alves, D. MACHO project 2nd year LMC microlensing results and dark matter implications, article, February 1996; California. (digital.library.unt.edu/ark:/67531/metadc696721/: accessed September 23, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.