Featured Research

from universities, journals, and other organizations

New 3D map of massive galaxies and black holes offers clues to dark matter, dark energy

Date:
August 8, 2012
Source:
Sloan Digital Sky Survey III
Summary:
Astronomers have constructed the largest-ever three-dimensional map of massive galaxies and distant black holes, which will help the investigation of the mysterious “dark matter” and “dark energy” that make up 96 percent of the universe.

Galaxies are concentrated into clusters and filaments with voids in between. The SDSS-III is exploring this structure to determine the nature of dark energy and the distribution of dark matter in the Universe.
Credit: Miguel A. Aragσn (Johns Hopkins University), Mark SubbaRao (Adler Planetarium), Alex Szalay (Johns Hopkins University), Yushu Yao (Lawrence Berkeley National Laboratory, NERSC), and the SDSS-III Collaboration

Astronomers have constructed the largest-ever three-dimensional map of massive galaxies and distant black holes, which will help the investigation of the mysterious "dark matter" and "dark energy" that make up 96 percent of the universe.

The map was produced by the Sloan Digital Sky Survey III (SDSS-III).

Early last year, the SDSS-III released the largest-ever image of the sky, which covered one-third of the night sky. The new data, "Data Release 9" (DR9), which publicly releases the data from the first two years of this six-year project, begins expansion of this earlier image into a full three-dimensional map.

"What really makes me proud of this survey is our commitment to creating a legacy for the future," said Michael Blanton, a New York University physics professor who led the team that prepared DR9. "Our goal is to create a map of the universe that will be used long after we are done, by future generations of astronomers, physicists, and the general public."

DR9 is the latest in a series of data releases stretching back to 2001. This release includes new data from the ongoing SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), which will eventually measure the positions of 1.5 million massive galaxies over the past seven billion years of cosmic time, as well as 160,000 quasars -- giant black holes actively feeding on stars and gas -- from as long ago as 12 billion years in the past.

BOSS is targeting these big, bright galaxies because they live in the same places as other galaxies and they're easy to spot, even far away in the universe. Mapping these big galaxies thus provides an effective way to make a map of the rest of the galaxies in the universe.

With such a map, scientists can retrace the history of the universe over the last seven billion years. With that history, they can get better estimates for how much of the universe is made up of "dark matter" -- matter that we can't directly see because it doesn't emit or absorb light -- and "dark energy," the even more mysterious force that drives the accelerating expansion of the universe.

"Dark matter and dark energy are two of the greatest mysteries of our time," said David Schlegel of Lawrence Berkeley National Laboratory, who led the SDSS-III effort to map these galaxies and quasars. "We hope that our new map of the universe can help someone solve the mystery."

That map of the universe is the centerpiece of DR9. The release includes images of 200 million galaxies and spectra of 1.35 million galaxies, including new spectra of 540,000 galaxies from when the universe was half its present age. Spectra show how much light a galaxy gives off at different wavelengths. Because this light is shifted to longer redder wavelengths as the universe expands, spectra allow scientists to figure out how much the universe has expanded since the light left each galaxy. The galaxy images, plus these measurements of expansion, are combined by SDSS-III scientists to create the three-dimensional map released with DR9.

Distant "quasars" provide another way to measure the distribution of matter in the universe. Quasars are the brightest objects in the distant universe and their spectra show intricate patterns imprinted by the large-scale clumping of intergalactic gas and underlying dark matter that lies between each quasar and Earth.

These new data are not only helping us understand the distant universe, but also our own cosmic backyard, the Milky Way galaxy. DR9 includes better estimates for the temperatures and chemical compositions of more than half a million stars in our own galaxy.

"With these better estimates, we can look back at the history of our galaxy," said Connie Rockosi of the University of California, Santa Cruz, who leads the SDSS-III's Milky Way study. "We can tell the story of how smaller galaxies came together to build up the Milky Way we see today."

All these new images and spectra contain the promise of new discoveries about our universe -- but the SDSS-III is only in the middle of its six-year survey.

"The most fun part of making this data available online is knowing that anyone on the Internet can now access the very same data and search tools that professional astronomers use to make exciting discoveries about our universe," said Ani Thakar of Johns Hopkins University.

And DR9 doubtless contains many surprises.

"This is science at its collaborative best," said Michael Wood-Vasey, a professor at the University of Pittsburgh and the scientific spokesperson for the SDSS-III collaboration. "SDSS-III scientists work together to address big questions extending from our own galaxy to distant reaches of the universe and then they share all of that data with the world to allow anyone to make the next big discovery."


Story Source:

The above story is based on materials provided by Sloan Digital Sky Survey III. Note: Materials may be edited for content and length.


Journal Reference:

  1. SDSS-III Collaboration: Ahn C. P. et al. The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey. Astrophysical Journal Supplement Series, 2012 [link]

Cite This Page:

Sloan Digital Sky Survey III. "New 3D map of massive galaxies and black holes offers clues to dark matter, dark energy." ScienceDaily. ScienceDaily, 8 August 2012. <www.sciencedaily.com/releases/2012/08/120808093445.htm>.
Sloan Digital Sky Survey III. (2012, August 8). New 3D map of massive galaxies and black holes offers clues to dark matter, dark energy. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2012/08/120808093445.htm
Sloan Digital Sky Survey III. "New 3D map of massive galaxies and black holes offers clues to dark matter, dark energy." ScienceDaily. www.sciencedaily.com/releases/2012/08/120808093445.htm (accessed July 25, 2014).

Share This




More Space & Time News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: ISS Cargo Ship Launches in Kazakhstan

Raw: ISS Cargo Ship Launches in Kazakhstan

AP (July 23, 2014) — The Progress 56 cargo ship launched from the Baikonur Cosmodrome in Kazakhstan Wednesday. NASA says it will deliver cargo and crew supplies to the International Space Station. (July 23) Video provided by AP
Powered by NewsLook.com
Raw: Cargo Craft Undocks from Space Station

Raw: Cargo Craft Undocks from Space Station

AP (July 22, 2014) — A Russian Soyuz cargo-carrying spacecraft undocked from the International Space Station on Monday. The craft is due to undergo about ten days of engineering tests before it burns up in the Earth's atmosphere. (July 22) Video provided by AP
Powered by NewsLook.com
NASA Ceremony Honors Moon Walker Neil Armstrong

NASA Ceremony Honors Moon Walker Neil Armstrong

AP (July 21, 2014) — NASA honored one of its most famous astronauts Monday by renaming a historic building at the Kennedy Space Center in Florida. It now bears the name of Neil Armstrong, the first man to walk on the moon. (July 21) Video provided by AP
Powered by NewsLook.com
Neil Armstrong's Post-Apollo 11 Life

Neil Armstrong's Post-Apollo 11 Life

Newsy (July 19, 2014) — Neil Armstrong gained international fame after becoming the first man to walk on the moon in 1969. But what was his life like after the historic trip? Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

More Coverage


First BOSS Data: 3-D Map of 500,000 Galaxies, 100,000 Quasars

Aug. 8, 2012 — Now available to the public: spectroscopic data from over 500,000 galaxies up to 7 billion light years away, over 100,000 quasars up to 11.5 billion light years away, and many thousands of other ... read more
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:  

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile iPhone Android Web
          Follow Facebook Twitter Google+
          Subscribe RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins