Astronomers Create 3D Map of the Distant Universe

A 3D Map of the Adolescent Universe

3D map of the cosmic web at a distance of 10.8 billion years from Earth, generated from imprints of hydrogen gas observed in the spectrum of 24 background galaxies behind the volume. This is the first time that large-scale structures in such a distant part of the Universe have been directly mapped. Credit: Casey Stark (UC Berkeley) and Khee-Gan Lee (MPIA)

Using a new technique similar to x-ray computer-tomographic imaging, a team of astronomers has created the first three-dimensional map of the adolescent Universe – just 3 billion years after the Big Bang.

Using extremely faint light from galaxies 10.8-billion light years away, scientists have created one of the most complete, three-dimensional maps of a slice of the adolescent universe. The map shows a web of hydrogen gas that varies from low to high density at a time when the universe was made of a fraction of the dark matter we see today.

The new study, led by Khee-Gan Lee and his team at the Max Planck Institute for Astronomy in conjunction with researchers at Berkeley Lab and UC Berkeley, will be published in an upcoming issue of Astrophysical Journal Letters.

In addition to providing a new map of part of the universe at a young age, says David Schlegel of Berkeley Lab, the work demonstrates a novel technique for high-resolution universe maps. The new technique, which uses distant galaxies to backlight hydrogen gas, might inform future mapping projects, he says. One such project could be the proposed Dark Energy Spectroscopic Instrument (DESI). Managed by Berkeley Lab, DESI has the goal of producing the most complete map of the universe yet.

“DESI was designed without the possibility of extracting such information from the most distant, faint galaxies,” says Schlegel, “Now that we know this is possible, DESI promises to be even more powerful.”

Lyman-alpha Forest Tomography of the Early Universe

Artist’s impression illustrating the technique of Lyman-alpha tomography: as light from distant background galaxies (yellow arrows) travel through the Universe towards Earth, they are imprinted by the absorption signatures from hydrogen gas tracing in the foreground cosmic web. By observing a number of background galaxies in a small patch of the sky, astronomers were able to create a 3D map of the cosmic web using a technique similar to medical computer tomography (CT) scans. Credit: Khee-Gan Lee (MPIA) and Casey Stark (UC Berkeley)

The first big 3D map of the universe was created using data from the Sloan Digital Sky Survey (SDSS), which began in 1998. Over the years, the survey has provided data to make a high-resolution map of the nearby universe, within about 1-billion light years. Recent telescope upgrades have stretched our ability to map the universe to about 6-billion light years, but, according to Schlegel, it’s a fairly crude map with incomplete data in some areas. The next generation of maps will come from the DESI project, scheduled to begin operation in 2018 pending funding. DESI will allow scientists to visualize 10 times the volume of SDSS and will extend about 10-billion light years away.

Beyond 10-billion light years, says Schlegel, the expectation was that the map would become sparse. The reason: astronomers planned to use a familiar technique that uses the bright light of quasars, which are, unfortunately, scattered and few. The technique uses a phenomenon called Lyman-alpha forest absorption, which relies on the fact that vast clouds of hydrogen exist between Earth and distant quasars and galaxies. At a certain distance, as measured by the red shift of the light, astronomers can determine the density of hydrogen, based on the absorption of quasar light. The problem is that this only provides information about the presence of hydrogen along the line of sight, not over a larger volume of space.

“It’s a pretty weird map because it’s not really 3D,” explains Schlegel. “It’s all these skewers; we don’t have a picture of what’s between the quasars, just what’s along the skewers.”

The researchers believe their new technique, which uses the faint light of numerous distant galaxies instead of that of sparse quasars, can fill in the gaps between these skewers.

Before this study, no one knew if galaxies further than 10-billion light years away could provide enough light to be useful, Schlegel says. But earlier this year, the team collected four hours of data on the Keck-1 telescope during a brief break in cloudy skies. “It turned out to be enough time to prove we could do this,” Schlegel says.

Of course, the galaxies’ light was indeed exceedingly faint. In order to use it for a map, the researchers needed to develop algorithms to subtract light from the sky that would otherwise drown out the galactic signals. Schlegel developed the algorithm to do this, while Casey Stark and Martin White of UC Berkeley modified an existing algorithm, called a Wiener filter, to create the 3D map within a minute on a standard laptop computer.

Because the project was a proof-of-concept, the researchers are planning future Keck-1 telescope time to extend the volume of space they map. “This technique is pretty efficient and it wouldn’t take a long time to obtain enough data to cover volumes hundreds of millions of light years on a side,” says Khee-Gan Lee.

This research was supported by the U.S. Department of Energy’s Office of Science and used the facilities of the National Energy Research Scientific Computing Center (NERSC) located at Berkeley Lab.

First Three Dimensional Map of the Adolescent Universe

Publication: (In press) K.G. Lee et al., “Lyα Forest Tomography from Background Galaxies: The first Megaparsec-Resolution Large-Scale Structure Map at z>2” in the Astrophysical Journal Letters.

PDF Copy of the Study: Lyman-alpha Forest Tomography from Background Galaxies: The First Megaparsec-Resolution Large-Scale Structure Map at z>2

Images: Casey Stark (UC Berkeley) and Khee-Gan Lee (MPIA)

11 Comments on "Astronomers Create 3D Map of the Distant Universe"

  1. There is CYAN-TRANSITIONGOING TO EMERGENCE in the dark space outside of the rectangle, in THE FIRST picture
    In usual pictures if you concentrate on the black space and not the white-LIGHT you can see dark energy which are gravity lines created BY E=G,WHICH =MC SQUARED

  2. That was 10 Billion years ago. Ever wonder what it’s like and where it is now? We’re seeing it as it was then. If the Universe is expanding where is it’s limit now? We’re only talking about the observable Universe so how big is it really?? Fun questions, no answers. Doesn’t really matter anyway.

    • The Same, light does not age, the photo is a picture of their NOW of 10 billion years ago, I as the observer, view their-then-now in our-now-view 10 BILLION YEARS LATER, (PRESENT-TIME)0ur-now,…. IF THE UNIVERSE IS EXPANDING IT-IS THE SAME SIZE BUT FURTHER AWAY-older there, older-here…. IF THE UNIVERSE IS STATIC,SAME SIZE same-age-there and here holo-deck-view …… IF THE UNIVERSE
      is contracting -closer-bigger there bigger-view-here HIT-US-(ANY-PRESENT-TIME) not so fun-pun-now unless they and we are holograms FROM-HERE-AND-FOREVER-NOW-ON BECAUSE WE WOULDN’T FEEL A THING!!! WELL AND-TRULY-DUSTED-AND-DEAD

    • Of course, it matters. I’ve been trying to make sense of this for more than two decades. We see the past; the distant past. We’re told that what we see is X light years away, as if what we see (or report) is what’s going on now.

      Stuff like this ought to be reported as “X billion years ago, this’s what was going on.” We’ve no idea what’s going on out there now. Well, we can possibly extrapolate somewhat, but for all we know, Vogons are building a hyperspace bypass out there now.

      Pretty pictures, interesting technique, and it’s been interesting watching this sort of thing develop since the discovery of gravitational lensing started us on this road.

  3. E=MC SQUARED.EINSTIEN
    G=MC SQUARED
    E=G, THAT’S A BIT BETTER PHI’= IF INSIDE L’if’E which= choice
    we live inside a 3D body that has a 4D MIND, A MINDFUL-CHOICE TO GIVE A 3D BRAIN A QUANTUM HEADACHE!!!

  4. PLEASE view Trieste picture Wikipedia 23rd January 1960 15 emergence in sky, 15 emergence in sea , either other life here or out there now been here for 55 or more years.

  5. orwell 1984 here covertly run by you-know-who the enemy within

  6. THIS WORLD-WIDE IS BUILT for entrapment so all of business, can somehow catch your data and covertly monitor you-me-every one else and more
    everything electronic is covertly watching and recording your actions
    your tv is included as a UHF RECIEVER, DISHER-OUT

  7. MUI DOES NOT WORK , the two systems will-not marry-up
    classical zero times zero equals zero
    classical zero divided by zero DOES NOT COMPUTE
    binary zero times zero equals zero equals zero
    binary zero divide by zero
    THEREFORE BOTH SYSTEMS ARE WRONG AS ZERO IS IN BOTH SYSTEMS

    BECAUSE BOTH SYSTEMS CAN’T BE RIGHT TOGETHER
    BECAUSE BOTH SYSTEMS CAN-NOT BE WRONG TOGETHER NOR RIGHT-TOGETHER
    ALSO LIKE-WISE THE LOGICAL-STATEMENT zero plus ‘or’ zero MINUS MUST BE O’K IN TRANSITION, HALF OF ONE ‘AND’

    THE OTHER ‘REVERSING IT’ HALF OF ‘ONE’ ‘OR’ THE OTHER, MUST BE
    RIGHT

    IN OTHER WORS NOTHING BUT QUANTUM MADNESS……..CHAOS AND WELL KAPUT TOGETHER

  8. Stephen Johnson | October 28, 2014 at 4:18 pm | Reply

    HE’S RIGHT UNO!!! FOR IT’S A MAD, MAD,MAD…CRAZY WORLD IF YOUR A QUANTA, WHO WAS GIVEN A QUARTER BOTTLE OF MILK A DAY TO IMPROVE HIS/HER SCHOOLING
    ON PORPOISE THEY TORTOISE WHATT!!! AND HOW TO TORQUE-THE-TORQUE TO ERG-US ON 2better thinks ….2 return, learn & earn…..ERNIE -PAY 4 THE DAY-O

  9. Question why is it that when you think of a model of our solar system or universe it seems to be circular expanding on the sides but not above and below there was to be something out there in those directions as well wright?

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