Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists determine large magellanic cloud galaxy formed similar to Milky Way

12.09.2003


An astronomer from the Lawrence Livermore National Laboratory, in collaboration with an international team of researchers, have discovered that a neighboring galaxy -- the Large Magellanic Cloud (LMC) -- appears to have formed with an old stellar halo, similar to how our very own Milky Way formed.



The oldest and most metal-poor Milky Way stars form a spherical halo where they move about like atoms in a hot gas, which in turn prompts two major formation scenarios of our galaxy: extended hierarchical accretion and rapid collapse. RR Lyrae stars, which are found both in the Milky Way and the LMC, are excellent tracers of old and metal-poor populations.

By measuring the movement of 43 RR Lyrae stars in the inner regions of the LMC, the team determined that a moving hot, metal-poor, old halo also exists in the LMC, suggesting that the Milky Way and smaller, more irregular galaxies like the LMC have similar early formation histories.


The research, titled "Kinematic Evidence for an Old Stellar Halo in the Large Magellanic Cloud," is featured in the Sept. 12 issue of Science.

Kem Cook of Livermore’s Institute of Geophysics and Planetary Physics and part of the Massive Compact Halo Objects (MACHO) team, which previously discovered the RR Lyrae stars in the LMC, noted that they are an easily identified tracer of an old, metal-poor population. The LMC is more than 160,000 light-years away from our galaxy.

"The bottom line is that the Large Magellanic Cloud seems to have had a similar early formation history as the Milky Way," Cook said. "It created a spherical component that is not rotationally supported, but the stars have high random velocities, like a hot gas."

Cook, along with scientists from Universidad Pontifica Catolica in Chile, the European Southern Observatory, Columbia Astrophysics Laboratory and the Mount Stromlo Observatory at The Australian National University, observed the LMC RR Lyrae stars in January 2003 and measured the radial velocity dispersion using the European Southern Obervatories VLT.

The large-velocity dispersion of the LMC RR Lyrae stars scales to the Milky Way RR Lyrae star’s velocity dispersion and indicates that metal-poor old stars in the LMC are distributed in a halo population.

Models of halo formation by accretion indicate that these old objects formed in small satellite galaxies that were subsequently accreted (eaten up) by the galaxy. Meanwhile, models of halo formation by dissipational collapse indicate that the halo formed rapidly before the disk collapsed. The researchers applied these models to smaller galaxies and observed a halo population in the LMC by its oldest objects.


Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by the University of California for the U.S. Department of Energy’s National Nuclear Security Administration.

Anne Stark | EurekAlert!
Further information:
http://www.berkeley.edu/

More articles from Physics and Astronomy:

nachricht CCNY physicists master unexplored electron property
26.07.2017 | City College of New York

nachricht Large, distant comets more common than previously thought
26.07.2017 | University of Maryland

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

 
Latest News

CCNY physicists master unexplored electron property

26.07.2017 | Physics and Astronomy

Molecular microscopy illuminates molecular motor motion

26.07.2017 | Life Sciences

Large-Mouthed Fish Was Top Predator After Mass Extinction

26.07.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>