Planck Time

VLT, Hubble Smash Record for Eyeing Most Distant Galaxy

Article written: 20 Oct , 2010
Updated: 24 Dec , 2015


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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23 Responses

  1. Don Alexander says

    “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…

  2. 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.

  3. Roen says

    @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 falls within that target period.

  4. Manu says

    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!

  5. Member
    Aqua says

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

  6. HeadAroundU says

    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.

  7. lars says

    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.

  8. Roen says

    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 the spectrum of the light that passes through the cloud. this happens because specific elements will absorb light in specific places in the spectrum. The light in those places is missing and appear dark. These are called absorption lines, not to be confused with emission lines. In this way we can learn what elements are contained within the given cloud, nebula, young stellar disks, and even the atmospheres of some exoplanets.

    Someday never comes (No offense, Lars ;). Now is always a good time.

  9. Astrofiend says

    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.

    October 20th, 2010 at 9:13 pm ”

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

  10. renoor says

    @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.

  11. renoor says

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

  12. Lawrence B. Crowell says

    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 equal to the energy it gives back climbing back out. Yet if the gravitational energy well evolves this balance is perturbed and results in small deviations in photon energy.

    This result is interesting, for it means galaxies formed comparatively quickly after the CMB period, and probably matter accreted into super massive black hole (SMBH) quickly as well. SMBHs could not have formed early on, say during the inflationary period, or prior to then. This would imply a larger entropy, or larger overall Weyl curvature, and a much larger anisotropy of the CMB.


  13. Roen says

    @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. 🙂

  14. jimhenson says

    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 the universe. Not all stars will be under 600 million years old in this galaxy, because it is just too far away, and even the fine-structure constant might vary especially in the early universe.

  15. Manu says

    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?

  16. HeadAroundU says

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

  17. Lawrence B. Crowell says

    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.


  18. Member
    Aqua says

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

  19. Vanamonde says

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

  20. Jon Hanford says

    “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 no expert, please feel free to correct!):

    “[UDFy-38135539] is estimated to have contained roughly a billion stars, although it was only at most one tenth of the diameter of our own galaxy, the Milky Way, and had less than 1% of the mass of the Milky Way’s stars. According to Lehnert (of the Observatoire de Paris), it was forming the same number of stars per year as our galaxy, but they were much smaller and less massive, making it “intensely star forming”.” ( )

    So this galaxy is about the size and mass of the Small Magellanic Cloud (which is~7000 ly diameter, ~7×10^9 Msolar mass) and not a “full sized”, Milky Way mass galaxy.

    Also, it is noted that the JWST should be able to detect galaxies 13.4 Gly distant, only ~300 Myr after the Big Bang (~150 Myr after the start of reionization). Those z=9-10 candidates in the HUDF surely await confirmation in the next few years. Webb GOTCHU! 😀

  21. jimhenson says

    the John Webb is set to launch in 2 years. should it discover even more evolved yet older ancient galaxies at even greater redshifts and distances, perhaps 15 billion light years, someone will get credit for having a better theory that supports new evidence that the universe is older then the big-bang. my theory: the big-bang energy expands at c speed limit, thus creating matter and mass. inflation from the big-bang pushes away pre-existing distant galaxies, because it was a huge local singularity implosion, and not everything like the birth of the universe. galaxies beyond our visible horizon already existed. the big-bang destroyed everything within our current visible horizon, but not beyond it where those ancient mature most distant visible galaxies have begun to be discovered.

  22. wjwbudro says

    @JIMHENSON Not to be disrespectful but, I believe the rules are clear.
    “Comment policy: Be nice and brief. Don’t advertise your stuff, or promote your personal theories. We’ll delete any comments that break these policies. Click here for more details.”
    It seems that whenever you post your pet theories, the discussion seems to abruptly end and that disappoints me.
    You might try posting on BAUT “against the mainstream”.

  23. Hannes says


    Einstein was against the mainstream also during his lifetime, as all other (now considered) outstanding physicists.

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