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TOPIC: Distant Galaxies


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RE: Distant Galaxies
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Catching a 'Wave' of Galaxies Ending the Dark Ages

Through a project dubbed SURFS UP, NASA's Spitzer Space Telescope and Hubble Space Telescope are catching sight of a "wave" of galaxies that emerged in the early universe. Starlight from these primordial galaxies is reckoned to have cleared a fog of hydrogen gas that shrouded the cosmos during a mysterious period known as the Dark Ages.
Spitzer has revealed that the stars shining in two of the young SURFS UP galaxies, discovered by Hubble, look surprisingly mature. The finding suggests these stars formed earlier than expected, and thus began lifting the cosmic fog sooner than previously thought.

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Some galaxies in the early universe grew up quickly

Some galaxies grew up in a hurry. Most of the galaxies that have been observed from the early days of the universe were young and actively forming stars. Now, an international team of astronomers, including Carnegie's Eric Persson and Andy Monson, have discovered galaxies that were already mature and massive in the early days. Fifteen mature galaxies were found at a record-breaking average distance of 12 billion light years, when the universe was just 1.6 billion years old. Their existence at such an early time raises new questions about what forced them to grow up so quickly. The finding is published by The Astrophysical Journal Letters.
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Quasar host galaxies
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Title: Quasar host galaxies in the SDSS Stripe 82
Authors: Jari Kotilainen. Renato Falomo, Daniela Bettoni, Kalle Karhunen, Michela Uslenghi

We present first results from our study of the properties of ~400 low redshift (z < 0.5) quasars, based on a large homogeneous dataset derived from the Stripe 82 area of the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7). For this sky region, deep (r~22.4) u,g,r,i,z images are available, up to ~2 mag deeper than standard SDSS images, allowing us to study both the host galaxies and the Mpc-scale environments of the quasars. This sample greatly outnumbers previous studies of low redshift quasar hosts, from the ground or from space. Here we report the preliminary results for the quasar host galaxies. We are able to resolve the host galaxy in ~80 % of the quasars. The quasar hosts are luminous and large, the majority of them in the range between M*-1 and M*-2, and with ~10 kpc galaxy scale-lengths. Almost half of the host galaxies are best fit with an exponential disk, while the rest are spheroid-dominated. There is a reasonable relation between the central black hole mass and the host galaxy luminosity.

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Astronomers find most distant galaxy to date

With the help of NASAs Hubble and Spitzer Space Telescopes, a team of astronomers led by Hopkins Wei Zheng has discovered the most distant - and, hence, the youngest - galaxy ever observed with high confidence.
The telescopes captured light from that galaxy when the universe, now 13.7 billion years old, was just 500 million years of age. The light travelled about 13.2 billion light years before reaching the telescopes.

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Seeing the Birth of the Universe in an Atom of Hydrogen

An international team of scientists led by researchers at Tel Aviv University have developed a method for detecting galaxies of stars that formed when the universe was in its infancy, during the first 180 million years of its existence. The method is able to observe stars that were previously believed too old to find, says Prof. Rennan Barkana of TAU's School of Physics and Astronomy.
Published in the journal Nature, the researchers' method uses radio telescopes to seek out radio waves emitted by hydrogen atoms, which were abundant in the early days of the universe. Emitting waves measuring about eight inches (21 centimetres) long, the atoms reflect the radiation of the stars, making their emission detectable by radio telescopes, explains Prof. Barkana. This development opens the way to learning more about the universe's oldest galaxies.

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Title: Stars throw their weight in old galaxies
Authors: Nate Bastian

The observation that old, massive galaxies have a larger fraction of low-mass stars than their younger, lower-mass counterparts adds to mounting evidence that star formation may have been different in the early Universe.

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Under 'dark halo' old galaxies have many more stars

Some of the oldest galaxies in the Universe have three times more stellar mass, and so many more stars, than all current models of galaxy evolution predict. The finding comes from the Atlas3D international team, led by Michele Cappellari (Oxford), and including ASTRON astronomers Paolo Serra, Raffaella Morganti and Tom Oosterloo, who found a way to remove the 'halo' of dark matter that has clouded previous calculations.
The team's analysis means that all current models, which assumed for decades that the light we observe from a galaxy can be used to infer its stellar mass, will have to be revised. It also suggests that researchers have a new riddle to ponder: exactly how galaxies forming so early in the life of the Universe got to be massive so fast. A report of the research is published in this week's Nature.

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Under 'dark halo' old galaxies have many more stars

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VLT Observations of Gamma-ray Burst Reveal Surprising Ingredients of Early Galaxies

An international team of astronomers has used the brief but brilliant light of a distant gamma-ray burst as a probe to study the make-up of very distant galaxies. Surprisingly the new observations, made with ESOs Very Large Telescope, have revealed two galaxies in the young Universe that are richer in the heavier chemical elements than the Sun. The two galaxies may be in the process of merging. Such events in the early Universe will drive the formation of many new stars and may be the trigger for gamma-ray bursts.
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NASA's Spitzer Finds Distant Galaxies Grazed on Gas

Galaxies once thought of as voracious tigers are more like grazing cows, according to a new study using NASA's Spitzer Space Telescope.
Astronomers have discovered that galaxies in the distant, early universe continuously ingested their star-making fuel over long periods of time. This goes against previous theories that the galaxies devoured their fuel in quick bursts after run-ins with other galaxies.

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NASA's Spitzer Finds Distant Galaxies Grazed on Gas

Galaxies once thought of as voracious tigers are more like grazing cows, according to a new study using NASA's Spitzer Space Telescope.
Astronomers have discovered that galaxies in the distant, early universe continuously ingested their star-making fuel over long periods of time. This goes against previous theories that the galaxies devoured their fuel in quick bursts after run-ins with other galaxies.

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