Looking back 13 billion (!) years i...(Oldest Galaxy)

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dutchie

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UDFy-38135539 Is Most Distant Galaxy Ever Measured
By News Staff | October 20th 2010 12:03 PM

Astronomers report they have measured the distance to the most remote galaxy and have found that they are seeing it when the Universe was only about 600 million years old (a redshift of 8.6), making those the first confirmed observations of a galaxy whose light is clearing the opaque hydrogen fog that filled the cosmos at this early time.

“Using the ESO Very Large Telescope we have confirmed that a galaxy spotted earlier using Hubble is the most remote object identified so far in the Universe” , says Matt Lehnert (Observatoire de Paris) who is lead author of the paper reporting the results. “The power of the VLT and its SINFONI spectrograph allows us to actually measure the distance to this very faint galaxy and we find that we are seeing it when the Universe was less than 600 million years old.”

Studying these first galaxies is extremely difficult. By the time that their initially brilliant light gets to Earth they appear very faint and small. Furthermore, this dim light falls mostly in the infrared part of the spectrum because its wavelength has been stretched by the expansion of the Universe — an effect known as redshift. To make matters worse, at this early time, less than a billion years after the Big Bang, the Universe was not fully transparent and much of it was filled with a hydrogen fog that absorbed the fierce ultraviolet light from young galaxies. The period when the fog was still being cleared by this ultraviolet light is known as the era of reionization.

(click the picture for a hires version) Astronomers using ESO’s Very Large Telescope (VLT) have now measured the distance to the most remote galaxy so far, UDFy-38135539 (the faint object shown in the excerpt on the left), which we see as it was when the Universe was only about 600 million years old (a redshift of 8.6). These are the first confirmed observations of a galaxy whose light is clearing the opaque hydrogen fog that filled the cosmos at this early time.
Credit:NASA, ESA, G. Illingworth (UCO/Lick Observatory and University of California, Santa Cruz) and the HUDF09 Team.


Despite these challenges the new Wide Field Camera 3 on the NASA/ESA Hubble Space Telescope discovered several robust candidate objects in 2009 that were thought to be galaxies shining in the era of reionization. Confirming the distances to such faint and remote objects is an enormous challenge and can only reliably be done using spectroscopy from very large ground-based telescopes, by measuring the redshift of the galaxy’s light.

Matt Lehnert says, “After the announcement of the candidate galaxies from Hubble we did a quick calculation and were excited to find that the immense light collecting power of the VLT, when combined with the sensitivity of the infrared spectroscopic instrument, SINFONI, and a very long exposure time might just allow us to detect the extremely faint glow from one of these remote galaxies and to measure its distance.”

They obtained telescope time on the VLT and observed the candidate galaxy called UDFy-38135539 for 16 hours. After two months of very careful analysis and testing of their results, the team found that they had clearly detected the very faint glow from hydrogen at a redshift of 8.6, which makes this galaxy the most distant object ever confirmed by spectroscopy. A redshift of 8.6 corresponds to a galaxy seen just 600 million years after the Big Bang.

[youtube]http://www.youtube.com/watch?v=RItsQAxbo7M[/youtube]
A European team of astronomers using ESO’s Very Large Telescope (VLT) has measured the distance to the most remote galaxy so far, UDFy-38135539. By carefully analysing the very faint glow of the galaxy they have found that they are seeing it when the Universe was only about 600 million years old (a redshift of 8.6). These are the first confirmed observations of a galaxy whose light is clearing the opaque hydrogen fog that filled the cosmos at this early time. Credit: ESO. Editing: Herbert Zodet. Written by: Richard Hook and Douglas Pierce-Price. Narration: Dr. J. Music: movetwo. Footage and photos: ESO, NASA, ESA, G. Illingworth (UCO/Lick Observatory and University of California, Santa Cruz) and the HUDF09 Team, A. M. Swinbank and S. Zieleniewski, M. Alvarez, R. Kaehler and T. Abel and José Francisco Salgado (josefrancisco.org). Directed by: Herbert Zodet. Executive producer: Lars Lindberg Christensen.

One of the surprising things about this discovery is that the glow from UDFy-38135539 seems not to be strong enough on its own to clear out the hydrogen fog. “There must be other galaxies, probably fainter and less massive nearby companions of UDFy-38135539, which also helped make the space around the galaxy transparent. Without this additional help the light from the galaxy, no matter how brilliant, would have been trapped in the surrounding hydrogen fog and we would not have been able to detect it”, explains co-author Mark Swinbank (Durham University).

Co-author Jean-Gabriel Cuby (Laboratoire d’Astrophysique de Marseille) remarks: “Studying the era of reionisation and galaxy formation is pushing the capability of current telescopes and instruments to the limit, but this is just the type of science that will be routine when ESO’s European Extremely Large Telescope — which will be the biggest optical and near infrared telescope in the world — becomes operational.”

Citation: M. D. Lehnert, N. P. H. Nesvadba, J.-G. Cuby, A. M. Swinbank, S. Morris, B. Cle´ment, C. J. Evans, M. N. Bremer&S. Basa, 'Spectroscopic confirmation of a galaxy at redshift z58.6', Nature Oct 21 2010 pp 940-942 doi:10.1038/nature09462

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Yes, it's a tiny, featureless blob, but this is light which was created some 13 billion years ago!! Some 600 million years after the creation of the universe. Awesome. Truly Awesome...
 
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Captain_Salty

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Re: Looking back 13 billion (!) years into history...

why does this galaxy "appear small" if we're seeing it when it was much closer?
is it actually a small galaxy, or can we only see a portion of it... or maybe something else entirely? :mrgreen:
 
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dutchie

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Re: Looking back 13 billion (!) years into history...

I must be quite dim and not understand your question, but if not, my answer would be: we're seeing it as a small object, because we're looking at something which is 13 bln. ly away. Any idea how that translates to miles/kilometres?
 
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origin

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Re: Looking back 13 billion (!) years into history...

Captain_Salty":w58fjh29 said:
why does this galaxy "appear small" if we're seeing it when it was much closer?
is it actually a small galaxy, or can we only see a portion of it... or maybe something else entirely? :mrgreen:

Because even though the galaxy was closer it was still very far away. The light that is now being emitted from the galalxy will never reach us.
 
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Archer17

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Re: Looking back 13 billion (!) years into history...

According to what I read about it on the BBC News site this galaxy is "quite small." An excerpt from the article:

"If you look at the object in the Hubble image, it really isn't much," said Dr Matt Lehnert of the Observatoire de Paris, France, and lead author on the Nature paper.

"We really don't know much about it, but it looks like it is quite small - much, much smaller than our own Milky Way Galaxy. It's probably got only a tenth to a hundredth of the stars in the Milky Way. And that's part of the difficulty in observing it - if it's not big, it's not bright," he told BBC News.

The entire piece, including a pic of the VLT/Sinfoni instrument used in conjunction with Hubble can be found here.
 
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SpeedFreek

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Re: Looking back 13 billion (!) years into history...

For a galaxy with a redshift of z=8.6:

The age at redshift z was 0.591 Gyr. - The universe was 591 million years old when that light was emitted.

The light travel time was 13.074 Gyr. - The light took just over 13 billion years to reach us.

The comoving radial distance, which goes into Hubble's law, is 9315.5 Mpc or 30.383 Gly. That galaxy is now over 30 billion light-years away.

The angular size distance is 970.4 Mpc or 3.1649 Gly. The galaxy was 3.1 billion light years away when that light was emitted.

The redshift of an object is an indication of the change in the scale factor of the universe between the light being emitted and us seeing it, using the form (1+z). So the universe is now 9.6 times larger than it was when that galaxy emitted the light we now see.

The original distance at emission (3.1649 Gly), multiplied by the scale factor 1+z (9.6) = the distance today (30.383 Gly)
 
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EarthlingX

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[youtube]http://www.youtube.com/watch?v=nflMBWxtmR8[/youtube]
ESOobservatory | October 21, 2010

A European team of astronomers using ESO's Very Large Telescope (VLT) has measured the distance to the most remote galaxy so far. By carefully analysing the very faint glow of the galaxy they have found that they are seeing it when the Universe was only about 600 million years old (a redshift of 8.6). These are the first confirmed observations of a galaxy whose light is clearing the opaque hydrogen fog that filled the cosmos at this early time.

Credit:

ESO. Visual design and editing: Martin Kornmesser and Luis Calçada. Editing: Herbert Zodet. Web and technical support: Lars Holm Nielsen and Raquel Yumi Shida. Written by: Richard Hook and Douglas Pierce-Price. Narration: Dr. J. Music: movetwo. Footage and photos: ESO, NASA, ESA, G. Illingworth (UCO/Lick Observatory and University of California, Santa Cruz) and the HUDF09 Team, A. M. Swinbank and S. Zieleniewski, M. Alvarez (http://www.cita.utoronto.ca/~malvarez), R. Kaehler and T. Abel and José Francisco Salgado (josefrancisco.org). Directed by: Herbert Zodet. Executive producer: Lars Lindberg Christensen.
 
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smwilson31

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Can any one enlighten me on how the hydrogen fog in the early universe was made. Was this the by product of matter and anti-matter annihilating each other, the remaining matter of which was hydrogen?

Kind Regards
 
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csmyth3025

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smwilson31":1nk3m9t7 said:
Can any one enlighten me on how the hydrogen fog in the early universe was made. Was this the by product of matter and anti-matter annihilating each other, the remaining matter of which was hydrogen?

Kind Regards
A good Wikipedia article that explains the "hydrogen fog" can be found here: http://en.wikipedia.org/wiki/Reionization

Another Wikipedia article that explains how the protons and neutrons that form the nuclei of hydrogen and helium are thought to have been created can be found here: http://en.wikipedia.org/wiki/Baryogenesis

Chris
 
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