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Posts Tagged ‘Star Formation’

Dark Matter Filaments Stoked Star Birth In Early Galaxies

From The New Scientist:

Tendrils of dark matter channelled gas deep into the hearts of some of the universe’s earliest galaxies, a new computer simulation suggests. The result could explain how some massive galaxies created vast numbers of stars without gobbling up their neighbours.

Dramatic bursts of star formation are thought to occur when galaxies merge and their gas collides and heats up. Evidence of these smash-ups is fairly easy to spot, since they leave behind mangled pairs of galaxies that eventually merge, their gas settling into a bright, compact centre.

Read more ….

Dark Matter Filaments Stoked Star Birth In Early Galaxies

From The New Scientist:

Tendrils of dark matter channelled gas deep into the hearts of some of the universe’s earliest galaxies, a new computer simulation suggests. The result could explain how some massive galaxies created vast numbers of stars without gobbling up their neighbours.

Dramatic bursts of star formation are thought to occur when galaxies merge and their gas collides and heats up. Evidence of these smash-ups is fairly easy to spot, since they leave behind mangled pairs of galaxies that eventually merge, their gas settling into a bright, compact centre.

Read more ….

Unprecedented 16-Year-Long Study Tracks Stars Orbiting Milky Way Black Hole

This is the central parts of our galaxy, the Milky Way, as observed in the near-infrared with the NACO instrument on ESO’s Very Large Telescope. By following the motions of the most central stars over more than 16 years, astronomers were able to determine the mass of the supermassive black hole that lurks there. (Credit: ESO/S. Gillessen et al.)

From Science Daily:

ScienceDaily (Dec. 10, 2008) — By watching the motions of 28 stars orbiting the Milky Way’s most central region with admirable patience and amazing precision, astronomers have been able to study the supermassive black hole lurking there. It is known as “Sagittarius A*” (pronounced “Sagittarius A star”). The new research marks the first time that the orbits of so many of these central stars have been calculated precisely and reveals information about the enigmatic formation of these stars — and about the black hole to which they are bound.

“The centre of the Galaxy is a unique laboratory where we can study the fundamental processes of strong gravity, stellar dynamics and star formation that are of great relevance to all other galactic nuclei, with a level of detail that will never be possible beyond our Galaxy,” explains Reinhard Genzel, leader of the team from the Max-Planck-Institute for Extraterrestrial Physics in Garching near Munich.

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Strangulation Of Spiral Galaxies: ‘Missing Link’ Discovered

These images of three galaxies from the Galaxy Zoo (top) and STAGES surveys (bottom) show examples of how the newly discovered population of red spiral galaxies on the outskirts of crowded regions in the Universe may be a missing link in our understanding of galaxy evolution. At left, both surveys find examples of normal spiral galaxies displaying all the hallmarks of youth: blue in colour, they are disk-like in structure. The obvious spiral arms host knotty structures where large numbers of hot young stars are being born. On the right are examples of typical rounded balls of stars known as elliptical galaxies. The reddish colour indicates that their stars are mostly old. With no gas left to use as fuel to form any more, they are old, dead and red In the centre are examples of the new “red spiral” galaxy found in large numbers by both the STAGES and Galaxy Zoo collaborations. While still disk-like and recognizably spiral in shape, their spiral arms are smoother. Furthermore, their colour is as red as the ellipticals. Astronomers from both teams believe these red spirals are objects in transition, where star formation has been shut off by interactions with the environment. (Credit: STAGES image credit: Marco Barden, Christian Wolf, Meghan Gray, the STAGES survey; STAGES image from Hubble Space Telescope, colour from COMBO-17 survey; Galaxy Zoo image credit: Sloan Digital Sky Survey)

From Science Daily:

ScienceDaily (Nov. 25, 2008) — Astronomers in two UK-led international collaborations have separately uncovered a type of galaxy that represents a missing link in our understanding of galaxy evolution.

Galaxy Zoo, which uses volunteers from the general public to classify galaxies, and the Space Telescope A901/902 Galaxy Evolution Survey (STAGES) projects have used their vast datasets to disentangle the roles of “nature” and “nurture” in changing galaxies from one variety to another.

Both studies have identified a population of unusual red spiral galaxies that are setting out on the road to retirement after a lifetime of forming stars. Crucially, nature and nurture appear to play a role in this transformation: both the mass of a galaxy as well as its local environment are important in determining when and how quickly its star formation is shut down. The scientists’ work appears together in a forthcoming edition of Monthly Notices of the Royal Astronomical Society.

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