25,335 science & technology articles
 

How much dark matter surrounds our Milky Way?

Posted on October 14, 2013

There are ‘hidden’ spots of dark matter located in space, according to some theories developed by modern astrophysicists. In fact, some of these structures also surround our Milky Way galaxy. However, it is difficult to prove this theory, as, based on the properties, which could be used indirectly to measure the amount of present dark matter, there are no visible objects (such as stars, dust, etc.) outside our galaxy. But scientists hope to solve this elusive problem with the new developments in the field of astronomical equipment and with some mathematical modeling.

Artist's conception of Gaia mapping the stars of the Milky Way.

Artist’s concept of the Gaia telescope  mapping the stars of the Milky Way.

Robert Feldmann from the University of California, Berkeley, USA, and Douglas Spolyar from the Paris Institute of Astrophysics, France, have performed high-resolution numerical simulations to verify the capabilities of the new ESA space telescope Gaia. Their work is available at arXiv.org.

The authors propose that the mentioned invisible structures of dark matter may be detected by measuring their gravitational pull on the stars from the Milky Way disk. This, in turn, could be estimated by analyzing the velocity dispersion of the stars located in different regions of the galaxy disk. Also, Feldmann and Spolyar state, that, in order to eliminate other possible impacts, the kinematic signature of the dark matter halo could be calculated by averaging a sufficiently large sample of velocities of the stars located in approximately same vicinity.

A low mass substructure (purple) passing vertically through the stellar disk of the MW (yellow). Tidal forces deform the substructure noticeably, but do not destroy it. The simulated impact occurs 8 kpc from the Galactic center at t=185 Myr.

A low mass substructure (purple) passing vertically through the stellar disk of the Milky Way (yellow). Tidal forces deform the substructure noticeably, but do not destroy it. The simulated impact occurs 8 kpc from the Galactic center at t=185 Myr.

Certainly, this investigation was performed only by a numerical simulation based on relatively approximate star velocity data. However, the authors hope that their framework will be useful in the nearest future for the upcoming astrometric Gaia mission. This mission should provide more precise information on the positions and motions of more than a billion stars in Milky Way. Therefore, astronomers hope to detect the kinematic signatures of dark matter structures around our galaxy.

The authors say that up to 20 dark matter structures should be detected in the outskirts of our galaxy if the cold dark matter theory is correct.

By Alius Noreika, Source: Technology.org

   
This entry was posted in Astronomy news, Authored post, Featured Space news, Spotlight news and tagged , , , . Bookmark the permalink.

Categories

Related Topics

Trending

General News

Follow us

Facebook   Twitter   Pinterest   StumbleUpon   Plurk
Google+   Tumblr   Delicious   RSS   Newsletter via Email