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TOPIC: Distant Galaxies


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MS1358arc
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Galaxies give birth to 50 stars a year
Young fertile galaxies give birth to stars such as the sun at a ''runaway'' rate of up to 50 a year, astronomers have learned.
The discovery shows that ''stellar nurseries'' within early galaxies similar to our own were producing stars far more rapidly than was previously thought.
Astronomers looked back 12.5 billion years to study one of the most distant galaxies known, MS1358arc.


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RE: Distant Galaxies
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The Universe's infant galaxies enjoyed rapid growth spurts forming stars like our Sun at a rate of up to 50 stars a year, according to scientists at Durham University. Led by RAS Norman Lockyer Fellow Dr Mark Swinbank, the team's work appears in Monthly Notices of the Royal Astronomical Society.
The findings show that "stellar nurseries" within the first galaxies gave birth to stars at a much more rapid rate than previously expected, the researchers from Durham's Institute for Computational Cosmology revealed. Their work appears in a paper in the journal Monthly Notices of the Royal Astronomical Society.
The research looked back 12.5 billion years to one of the most distant known galaxies, seen as it appeared about one billion years after the Big Bang.

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"Dropouts" pinpoint earliest galaxies
Astronomers, conducting the broadest survey to date of galaxies from about 800 million years after the Big Bang, have found 22 early galaxies and confirmed the age of one by its characteristic hydrogen signature at 787 million years post Big Bang. The finding is the first age-confirmation of a so-called dropout galaxy at that distant time and pinpoints when an era called the reionisation epoch likely began. The research will be published in a December issue of the Astrophysical Journal.
With recent technological advancements, such as the Wide-Field Camera 3 on the Hubble Space Telescope, there has been an explosion of research of the reionisation period, the farthest back in time that astronomers can observe. The Big Bang, 13.7 billion years ago, created a hot, murky universe. Some 400,000 years later, temperatures cooled, electrons and protons joined to form neutral hydrogen, and the murk cleared. Some time before 1 billion years after the Big Bang, neutral hydrogen began to form stars in the first galaxies, which radiated energy and changed the hydrogen back to being ionised. Although not the thick plasma soup of the earlier period just after the Big Bang, this star formation started the reionisation epoch. Astronomers know that this era ended about 1 billion years after the Big Bang, but when it began has eluded them and intrigued researchers like lead author Masami Ouchi of the Carnegie Observatories.

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Scientists have found the most distant galaxy cluster ever observed and believe the discovery might provide clues as to how the universe was formed.
The cluster, known as JKCS041, is about 10.2 billion light years away and was observed as it was when the universe was a quarter of its present age, the National Aeronautics and Space Administration (NASA) said.


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-- Edited by Blobrana on Saturday 24th of October 2009 11:52:24 PM

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Passive Red Spirals
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Title: Galaxy Zoo: Passive Red Spirals
Authors: Karen L. Masters (ICG, Portsmouth), Moein Mosleh (Sussex/Leiden), A. Kathy Romer (Sussex), Robert C. Nichol (ICG), Steven P. Bamford (Nottingham), Kevin Schawinski (Yale), Chris J. Lintott (Oxford), Dan Andreescu, Heather C. Campbell, Ben Crowcroft, Isabelle Doyle, Edward M. Edmondson, Phil Murray, M. Jordan Raddick, Anze Slosar, Alexander S. Szalay, Jan Vandenberg
(Version v2)

We study the spectroscopic properties and environments of red spiral galaxies found by the Galaxy Zoo project. By carefully selecting face-on, disk dominated spirals we construct a sample of truly passive disks (not dust reddened, nor dominated by old stellar populations in a bulge). As such, our red spirals represent an interesting set of possible transition objects between normal blue spirals and red early types. We use SDSS data to investigate the physical processes which could have turned these objects red without disturbing their morphology. Red spirals prefer intermediate density regimes, however there are no obvious correlations between red spiral properties and environment - environment alone is not sufficient to determine if a galaxy will become a red spiral. Red spirals are a small fraction of spirals at low masses, but dominate at large stellar masses - massive galaxies are red independent of morphology. We confirm that red spirals have older stellar populations and less recent star formation than the main spiral population. While the presence of spiral arms suggests that major star formation cannot have ceased long ago, we show that these are not recent post-starbursts, so star formation must have ceased gradually. Intriguingly, red spirals are ~4 times more likely than normal spirals to host optically identified Seyfert/LINER, with most of the difference coming from LINER-like emission. We find a curiously large bar fraction in the red spirals suggesting that the cessation of star formation and bar instabilities are strongly correlated. We conclude by discussing the possible origins. We suggest they may represent the very oldest spiral galaxies which have already used up their reserves of gas - probably aided by strangulation, and perhaps bar instabilities moving material around in the disk.

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Scientists have captured images of some of the universe's most distant galaxies thanks to a refurbished space telescope.
Ross McLure and James Dunlop of Edinburgh University were part of team which analysed the latest images of deep space beamed down from the Hubble space telescope.

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Looking almost 11 billion years into the past, astronomers have measured the motions of stars for the first time in a very distant galaxy and clocked speeds upwards of one million miles per hour, about twice the speed of our Sun through the Milky Way.
The fast-moving stars shed new light on how these distant galaxies, which are a fraction the size of our Milky Way, may have evolved into the full-grown galaxies seen around us today. The results will be published in the August 6, 2009 issue of the journal Nature, with a companion paper in the Astrophysical Journal.


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UH astronomers see earliest galaxies
University of Hawaii astronomers and colleagues have observed the first galaxies formed shortly after the universe began with the Big Bang 13.7 billion years ago.

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Keck Laser Helps Astronomers Probe the Nature of Massive Galaxies in the Early Universe
Astronomers using the W. M. Keck Observatory have discovered distant galaxies as massive as the Milky Way yet ten to 1000 times more compact. The new results, announced June 9 at the 214th American Astronomical Society meeting in Pasadena, provide astronomers with surprising clues about early star and galaxy formation at a time when the Universe was just a few billion years old.

The shapes of these galaxies tell us that it is not reasonable to expect they could occur from mergers. Instead, the kind of disks were seeing and the constituent stars seemed to have formed all at once, directly from the gas. In the old lingo, this is monolithic galaxy formation - astronomer Alan Stockton of the University of Hawaii.

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Researchers have observed so-called monster galaxies in a group for the first time, according to the May 7 edition of science magazine Nature.
A study group comprising researchers of the National Astronomical Observatory, Tokyo University and other entities observed the group of galaxies with the Atacama Submillimeter Telescope Experiment (ASTE) radio telescope in Chile.


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