Clearing the cosmic fog: The most distant galaxy ever measured (w/ Video)

Oct 20, 2010
Astronomers using ESO’s Very Large Telescope (VLT) have measured the distance to the most remote galaxy so far, UDFy-38135539, existing when the Universe was only about 600 million years old (a redshift of 8.6). Image: M. Alvarez, R. Kaehler, and T. Abel

(PhysOrg.com) -- 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. It has taken 13.1 billion years, travelling at 300,000 kilometres (186,000 miles) per second, for this smudge of infant light to arrive.

The results will appear in the 21 October issue of the journal Nature.

"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 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 . 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 fog that absorbed the fierce ultraviolet light from young galaxies. The period when the fog was still being cleared by this is known as the era of reionisation. Despite these challenges the new Wide Field Camera 3 on the NASA/ESA discovered several robust candidate objects in 2009 that were thought to be galaxies shining in the era of reionisation. 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.

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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

Matt Lehnert takes up the story: "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."

On special request to ESO's Director General they obtained telescope time on the VLT and observed a 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 .

Co-author Nicole Nesvadba (Institut d'Astrophysique Spatiale) sums up this work, "Measuring the redshift of the most distant galaxy so far is very exciting in itself, but the astrophysical implications of this detection are even more important. This is the first time we know for sure that we are looking at one of the galaxies that cleared out the fog which had filled the very early Universe."

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 , 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."

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StarDust21
5 / 5 (1) Oct 20, 2010
interesting sutff
yyz
5 / 5 (7) Oct 20, 2010
Definitely pushing the limits of ground based spectroscopy. The identification of the Lyman alpha line of hydrogen allowed for the galaxy's distance to be measured. At rest, this line lies in the far-UV part of the spectrum at 1216 A. The VLT measured this line at 11,616 A in the near IR! Due to the extreme distance, little can be said about the galaxy itself but is noted as being rather average in luminosity and mass.

Hopefully, they're on to something here. Candidate galaxies in the Hubble Ultra Deep Field have been identified with photometric redshifts of 9-10. These objects will likely need the power of Webb Telescope and 30+m giant scopes now on the drawing boards to obtain useful spectra (the extreme redshift example seen here is a big reason future scopes -Webb et al- are optimized for near-to-mid IR wavelengths).

Nature paper: http://www.eso.or...1041.pdf
TDK
3.7 / 5 (3) Oct 20, 2010
The same story with picture, which appears more relevant for me
http://www.bbc.co...11580789
TehDog
not rated yet Oct 20, 2010
Both links are appreciated, I'd not noticed the BBC story, and the .pdf looks like interesting reading.
kevinrtrs
1.6 / 5 (9) Oct 21, 2010
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.

Maybe it's because there wasn't any fog to start off with because the whole Big Bang model in wrong. It certainly is being falsified at every turn and at every falsification more ad-hoc assumptions are required to bring the observations in line with the theory. Here we have exactly such a case - the galaxy is seen clearly but should have been obscured by fog. However, it's not the theory that gets thrashed, rather it's that there must be some other auxilliary objects that helped the galaxy shine thru the fog. I now predict there'll be even more surprises in store: not enough time dilation, not enough development and the galaxy will look strangely just like ones much closer to us.
genastropsychicallst
1 / 5 (6) Oct 21, 2010
... tele- by clearing for molecules the particles are fogging, fogging are particles the molecules for clearing by -scope ...
Quantum_Conundrum
1.5 / 5 (8) Oct 21, 2010
It has taken 13.1 billion years, travelling at 300,000 kilometres (186,000 miles) per second, for this smudge of infant light to arrive.


that would mean the galaxy was 13.1 billion ly away 13.1 billion years ago. Which would place it far, far outside our light horizon today.

The Big Bang theory is such an inconsistent joke. Seriously folks. they've gotta come up with something better than this crap.
Titto
1.4 / 5 (9) Oct 21, 2010
Maybe that galaxy is the centre and we are distant??? Who is moving?
Ye the Big Bang theory is for those who believes that nothing is something and life comes from nothing?
If I crack open a stone one day and find something like a tablespoon inside, then yes!! Maybe something can develop by itself???
CSharpner
5 / 5 (6) Oct 21, 2010
that would mean the galaxy was 13.1 billion ly away 13.1 billion years ago. Which would place it far, far outside our light horizon today.

Imagine you're onboard the Enterprize D. You seaparte the saucer section from the engineering section and send them off in opposite directions, each tavelling at 1/2 light speed from the origin. 1 year later, they've each traveled 1/2 a light year (1 ly total). At that time, the engineering section flashes a super bright light, just outside itself. 1 yr later, that flash arrives at where the saucer section /was/ a year earlier, but is now 1/2 a ly further away. 1/2 year later, the light arrives where the saucer section /was/, but has moved on. Eventually, the light will catch up to the saucer section, but the saucer section will be nearly 2 ly away from where the flash originated and it will appear to be that far away.
CSharpner
5 / 5 (5) Oct 21, 2010
It certainly is being falsified at every turn and at every falsification more ad-hoc assumptions are required to bring the observations in line with the theory.

That's a description of the idea that the universe is only 6,000 years old.
TDK
1.8 / 5 (5) Oct 21, 2010
The Big Bang theory is such an inconsistent joke
Is 600 millions of years enough for formation of galaxy? We should consider, with Big Bang theory the reionization period has finished one billion years after Big Bang, so that this galaxy has been actually formed during it.

http://en.wikiped...on_years
Pyle
5 / 5 (2) Oct 21, 2010
that would mean the galaxy was 13.1 billion ly away 13.1 billion years ago. Which would place it far, far outside our light horizon today.

Yes, it is, in your words, "outside our light horizon today." That is why we are looking at light it made 13.1 billion years ago. What is your point?

What does your comment have to do with any inconsistency?
Titto
1 / 5 (2) Oct 23, 2010
It is funny how we measure in years??? Say one is milliones of miles away from our planet which orbits our sun and that is one year?Are we still measuring then in years?????
The problem folks....nobody knows what time/distance really is? We just do not know!