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Z ~ 11 galaxy observed by CLASH most distant as of Nov 2012

by marcus
Tags: 2012, clash, distant, galaxy, observed
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marcus
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Nov16-12, 07:40 PM
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http://arxiv.org/abs/1211.3663
CLASH: Three Strongly Lensed Images of a Candidate z ~ 11 Galaxy
Dan Coe et al
(Submitted on 15 Nov 2012)
We present a candidate for the most distant galaxy known to date with a photometric redshift z = 10.7 +0.6 / -0.4 (95% confidence limits; with z < 9.5 galaxies of known types ruled out at 7.2-sigma). This J-dropout Lyman Break Galaxy, named MACS0647-JD, was discovered as part of the Cluster Lensing and Supernova survey with Hubble (CLASH). We observe three magnified images of this galaxy due to strong gravitational lensing by the galaxy cluster MACSJ0647.7+7015 at z = 0.591. The images are magnified by factors of ~8, 7, and 2,...
...This would suggest that low luminosity galaxies could have reionized the universe. However given the significant uncertainties based on only two galaxies, we cannot yet rule out the sharp drop off in number counts at z >~ 10 suggested by field searches.
Accepted for publication in the Astrophysical Journal. 23 pages, 18 figures
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marcus
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Nov16-12, 07:49 PM
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NASA press release about MACS0647-JD
http://www.nasa.gov/mission_pages/hu...ce-record.html (dated 15 November)
Go there to see the pictures. Here's a sample of the text:
==quote==
By combining the power of NASA's Hubble and Spitzer space telescopes and one of nature's own natural "zoom lenses" in space, astronomers have set a new record for finding the most distant galaxy seen in the universe.
The newly discovered galaxy, named MACS0647-JD, is very young and only a tiny fraction of the size of our Milky Way. The object is observed 420 million years after the big bang. The inset at left shows a close-up of the young dwarf galaxy. This image is a composite taken with Hubble's WFC 3 and ACS on Oct. 5 and Nov. 29, 2011. Credit: NASA, ESA, and M. Postman and D. Coe (STScI) and CLASH Team.
The farthest galaxy appears as a diminutive blob that is only a tiny fraction of the size of our Milky Way galaxy. But it offers a peek back into a time when the universe was 3 percent of its present age of 13.7 billion years.The newly discovered galaxy, named MACS0647-JD, was observed 420 million years after the big bang, the theorized beginning of the universe. Its light has traveled 13.3 billion years to reach Earth.

This find is the latest discovery from a program that uses natural zoom lenses to reveal distant galaxies in the early universe. The Cluster Lensing And Supernova Survey with Hubble (CLASH),an international group...

MACS0647-JD is so small it may be in the first steps of forming a larger galaxy. An analysis shows the galaxy is less than 600 light-years wide. Based on observations of somewhat closer galaxies, astronomers estimate that a typical galaxy of a similar age should be about 2,000 light-years wide. For comparison, the Large Magellanic Cloud, a dwarf galaxy companion to the Milky Way, is 14,000 light-years wide. Our Milky Way is 150,000 light-years across.

"This object may be one of many building blocks of a galaxy,"said the study's lead author, Dan Coe of the Space Telescope Science Institute. "Over the next 13 billion years, it may have dozens, hundreds, or even thousands of merging events with other galaxies and galaxy fragments."

Redshift is a consequence of the expansion of space over cosmic time. Astronomers study the distant universe in near-infrared light because the expansion of space stretches ultraviolet and visible light from galaxies into infrared wavelengths. Coe estimates MACS0647-JD has a redshift of 11, the highest yet observed.
=endquote=
Drakkith
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Nov16-12, 08:14 PM
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600 light years across? That's TINY!

marcus
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Nov16-12, 08:48 PM
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Z ~ 11 galaxy observed by CLASH most distant as of Nov 2012

Right! it is tiny! seems more like what we would call a "globular cluster" in size, or what people call a "proto-galaxy". It's amazing that they could see something like that at z>10.
Drakkith
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Nov16-12, 09:01 PM
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Quote Quote by marcus View Post
Right! it is tiny! seems more like what we would call a "globular cluster" in size, or what people call a "proto-galaxy". It's amazing that they could see something like that at z>10.
Yep. That's crazy!
jim mcnamara
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Nov16-12, 09:22 PM
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[ ]reionized the universe[ ]
Please, is there a discussion of what this means in a form where non-cosmologists can absorb it?

For example, if we have a "re"-ionized state then we must have had a prior state - maybe "de"-ionized?
Drakkith
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Nov16-12, 09:23 PM
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Quote Quote by jim mcnamara View Post
Please, is there a discussion of what this means in a form where non-cosmologists can absorb it?

For example, if we have a "re"-ionized state then we must have had a prior state - maybe "de"-ionized?

Here you go: http://en.wikipedia.org/wiki/Reionization
http://en.wikipedia.org/wiki/Chronol...e#Reionization
Chronos
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Nov16-12, 11:05 PM
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These very young 'galaxies' probably resemble the appearance of our own Milky Way some 500 million years after the BB.
surajt88
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Nov17-12, 10:57 AM
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Over the next 13 billion years, it may have dozens, hundreds, or even thousands of merging events with other galaxies and galaxy fragments.
I love it when astronomers (or people proficient in the field) speak in "future tense" for things that have taken place millions of years before now.!!
I'd put it "By now, the galaxy might have had dozens, hundreds, or even thousands of merging events with other galaxies and galaxy fragments"
Great discovery by the way. I'm amazed.!!


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