Planck Time

VLT, Hubble Smash Record for Eyeing Most Distant Galaxy

20 Oct , 2010 by

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Using the Hubble Space Telescope and the Very Large Telescope (VLT), astronomers have looked back to find the most distant galaxy so far. “We are observing a galaxy that existed essentially when the Universe was only about 600 million years old, and we are looking at this galaxy – and the Universe – 13.1 billion years ago,” said Dr. Matt Lehnert from the Observatoire de Paris, who is the lead author of a new paper in Nature. “Conditions were quite different back then. The basic picture in which this discovery is embedded is that this is the epoch in which the Universe went from largely neutral to basically ionized.”

Lehnert and an international team used the VLT to make follow-up observations of the galaxy — called UDFy-38135539 – which Hubble observations in 2009 had revealed. The astronomers analyzed the very faint glow of the galaxy to measure its distance — and age. This is the first confirmed observations of a galaxy whose light is emerging from the reionization of the Universe.

The reionization period is about 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 ionized. Although not the thick plasma soup of the earlier period just after the Big Bang, this galaxy formation started the reionization epoch, clearing the opaque hydrogen fog that filled the cosmos at this early time.

A simulation of galaxies during the era of deionization in the early Universe. Credit: M. Alvarez, R. Kaehler, and T. Abel

“The whole history of the Universe is from the reionization,” Lehnert said during an online press briefing. “The dark matter that pervades the Universe began to drag the gas along and formed the first galaxies. When the galaxies began to form, it reionized the Universe.”

UDFy-38135539 is about 100 million light-years farther than the previous most distant object, a gamma-ray burst.

Studying these first galaxies is extremely difficult, Lehnert said, as the 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. During the time of less than a billion years after the Big Bang, the hydrogen fog that pervaded the Universe absorbed the fierce ultraviolet light from young galaxies.

The new Wide Field Camera 3 on the NASA/ESA Hubble Space Telescope discovered several candidate objects in 2009, and with 16 hours of observations using the VLT, the team was able to was used to detect the very faint glow from hydrogen at a redshift of 8.6.

The team used the SINFONI infrared spectroscopic instrument on the VLT and a very long exposure time.

“Measuring the redshift of the most distant galaxy so far is very exciting in itself,” said co-author Nicole Nesvadba (Institut d’Astrophysique Spatiale), “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 galaxies, probably fainter and less massive nearby companions of UDFy-38135539,” said co-author Mark Swinbank from Durham University, “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.”

Sources: ESO, press briefing

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Don Alexander
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Don Alexander
October 20, 2010 11:57 AM

“UDFy-38135539 is about 100 million light-years farther than the previous most distant object, a gamma-ray burst.”

This means war!!! :@

Also, this is incorrect, it’s only 32 million years earlier using WMAP concordance cosmology. And 12 BILLION light years “further” in terms of luminosity distance…

Dr. Paul Cook
Member
October 20, 2010 2:12 PM

Interesting. Here we have a galaxy that’s recognizably a galaxy existing 400,000 years BEFORE galaxies are thought to be able to form (after about a billion years). How is that possible? Seems to me that we’re seeing a galaxy, fully formed after at least 10 billion years, at a distance of 12.8 billion light years. Someone has to come up with a theory as to how a galaxy formed just 600,000 years after the Big Bang when hydrogen hadn’t even begun cooling.

Roen
Member
Roen
October 20, 2010 2:42 PM
@Dr. Paul Cook: The previously known furthest was IOK-1 @ 12.9 billion ly (750 million years ATB). As stated in the article UDFy-38135539 is about 100 million years before that. . Between that and 1 billion years ATB the first stars formed in galaxies. “Someone has to come up with a theory as to how a galaxy formed just 600,000 years after the Big Bang when hydrogen hadn’t even begun cooling.” With respect, I don’t see a problem with the distances or the time between the cooling and the formation of a galaxy 6 million years ATB. It is believed that the first galaxies formed 1 BY ATB (between 400,000 years ATB and 1 BY ATB). This galaxy… Read more »
Manu
Member
Manu
October 20, 2010 4:12 PM

There’s one thing I never got right.
I understand the CMB was allowed to ‘escape’ when the plasma neutralized, and light could fly straight. It was visible (black body) light at this time, not yet redshifted to microwaves, right?
But the resulting neutral H2 is also supposed to have been opaque, until the much later reionization.
How could the CMB light propagate during that first billion years then? Ha!

Aqua4U
Member
October 20, 2010 5:00 PM

“…a redshift of 8.6…” Come ON JWST! HO!

HeadAroundU
Member
October 20, 2010 5:06 PM

Manu, I’m not an expert but we use infrared telescopes to penetrate a dust. Microwave light is even more to the left on EM spectrum. It goes through everything, I guess.

lars
Member
lars
October 20, 2010 9:13 PM

No, what you can say is, this galaxy has the highest redshift ever measured.

Someday you will understand what redshift is actually telling you, and it ain’t solely cosmological distance.

Roen
Member
Roen
October 20, 2010 9:53 PM
Red shift can be caused by intense gravitational fields that lengthens the wavelength, shifting it toward the red end of the spectrum. The motion and angular momentum of celestial objects can be studied by looking at the red shift (and blue shift). The universal expansion was discovered due to the fact that nearly all galaxies are shifted into the red. As galaxies are pulled away from each other by the universal expansion, the amount that the wavelength is lengthened indicates how far away the galaxy in question is. There are many wonderful things that can be discovered just by studying the spectrum of light. As light shines through a dust cloud, for example, dark lines will appear in… Read more »
Astrofiend
Member
Astrofiend
October 20, 2010 11:16 PM

Ooooh baby – can’t wait for JWST, GMT and the like to start sinking their teeth into these. A JWST deep-field will be a beautiful thing to behold.

“lars
October 20th, 2010 at 9:13 pm ”

Well by all means enlighten us Lars! Are you sitting on a big discovery?!

renoor
Member
renoor
October 21, 2010 12:25 AM

@manu, intereresting question! I’m not an expert too, but I think that after just few milion years the bacground radiation was alredy in deep infrared wavelengths, because the decrease in wavelength should be exponential, not linear.

renoor
Member
renoor
October 21, 2010 2:00 AM

i’m very sorry, of course it’s INCREASE and LOGARHYTMIC

Lawrence B. Crowell
Member
Lawrence B. Crowell
October 21, 2010 4:55 AM
Roen: I think you are referring to the integrated Sachs-Wolfe effect due to gravitational red shift in the post CMB period, or equivalently in space between the surface of last scatter and the present here on Earth. So this is not integral to the CMB. Gravitational wells evolve significantly if they are not due to ordinary luminous matter that tends to accumulate by dissipation. So dark energy or small regions of gravitational energy may have existed shortly after the surface of last scattering which red shifted photons passing through them. If the gravitational potential energy were static the energy of the photon would exhibit no change in its energy, for the energy it gains falling in would be… Read more »
Roen
Member
Roen
October 21, 2010 6:23 AM

@Lawrence: I was actually providing details that were not provided by lars in his comment “Someday you will understand what redshift is actually telling you, and it ain’t solely cosmological distance.” I felt that whoever he was talking to would appreciate a general run down of what can be learned from red shift data and how red shift could be caused. But tyvm for the additional information, it gives me yet another direction for further study. smile

jimhenson
Guest
jimhenson
October 21, 2010 3:23 PM
what needs to be realized is that in the future, more powerful telescopes will always find new record setting older galaxies. Why? Because it is ignorance for anyone to be dating the age of the universe. They don’t even know if parallel universes exist nor what is out far beyond the visible horizon. we have the oldest galaxy ever discovered, but it has to fit their model of the universe, so that the universe was only 600 million years old. How stupid. nobody even knows nor can agree with what the UNIVERSE IS for pity sakes! I’m certain there will be stars in this galaxy, that are far older then what is believed to be the age of… Read more »
Manu
Member
Manu
October 21, 2010 1:46 PM

Headaroundu, Renoor: thanks!
I guess you’re on the right track. Still, the universe being way denser when the CMB was visible light, the early thousands of years should have the most impact.
This leads to 2 more questions:
– how “opaque” is H2 actually?
– what proportion of the CMB has been lost to absorption?

HeadAroundU
Member
October 21, 2010 9:45 PM

Well, Manu, I thought that CMB was microwave light right from the beginning. grin

Lawrence B. Crowell
Member
Lawrence B. Crowell
October 22, 2010 9:12 AM

The CMB is from the end of the radiation dominated period of the universe. That is 380,000 years into the universe, which is close to the beginning.

LC

Aqua4U
Member
October 22, 2010 3:35 PM

I can see the headlines now…. JWST discovers galaxies at a redshift of 10.2!

Vanamonde
Member
Vanamonde
October 22, 2010 10:23 PM

Any one know if there is any evidence of Population III stars? Can we get a spectrum from this dot?

Jon Hanford
Member
Jon Hanford
October 23, 2010 6:12 AM
“Here we have a galaxy that’s recognizably a galaxy existing 400,000 years BEFORE galaxies are thought to be able to form (after about a billion years). How is that possible? Seems to me that we’re seeing a galaxy, fully formed after at least 10 billion years, at a distance of 12.8 billion light years. Someone has to come up with a theory as to how a galaxy formed just 600,000 years after the Big Bang when hydrogen hadn’t even begun cooling.” IIRC, current theory suggests galaxies could have formed as early as 200 Myr after the Big Bang. Also, this particular galaxy is far from being “fully formed”. From Wiki (standard disclaimer: this info appears correct, but I’m… Read more »
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