Two views of the Laniakea Supercluster. The outer surface shows the region dominated by Laniakea’s gravity. The streamlines shown in black trace the paths along which galaxies flow as they are pulled closer inside the supercluster. Individual galaxies’ colors distinguish major components within the Laniakea Supercluster: the historical Local Supercluster in green, the Great Attractor region in orange, the Pavo-Indus filament in purple, and structures including the Antlia Wall and Fornax-Eridanus cloud in magenta. Credit: SDvision interactive visualization software by DP at CEA/Saclay, France.
This is a short
video about Laniakea that gives the viewer a general sense of the
structure of our home supercluster and of galaxy motions in the nearby
Universe. Credit: This video is a preview of "Laniakea Supercluster", a
film produced as part of the following publication: "The Laniakea
Supercluster of Galaxies" published in Nature, volume 513, number 7516,
p.71 (4 September 2014) by R. Brent Tully, Hélène Courtois, Yehuda
Hoffman, and Daniel Pomarède.
Astronomers using the National Science Foundation’s Green Bank Telescope (GBT)
-- among other telescopes -- have determined that our own Milky Way
galaxy is part of a newly identified ginormous supercluster of galaxies,
which they have dubbed “Laniakea,” which means “immense heaven” in
Hawaiian.
This discovery clarifies the boundaries of our
galactic neighborhood and establishes previously unrecognized linkages
among various galaxy clusters in the local Universe.
“We have
finally established the contours that define the supercluster of
galaxies we can call home,” said lead researcher R. Brent Tully, an
astronomer at the University of Hawaii at Manoa. “This is not unlike
finding out for the first time that your hometown is actually part of
much larger country that borders other nations.”
The paper explaining this work is the cover story of the September 4 issue of the journal Nature.
Superclusters
are among the largest structures in the known Universe. They are made
up of groups, like our own Local Group, that contain dozens of galaxies,
and massive clusters that contain hundreds of galaxies, all
interconnected in a web of filaments. Though these structures are
interconnected, they have poorly defined boundaries.
To better
refine cosmic mapmaking, the researchers are proposing a new way to
evaluate these large-scale galaxy structures by examining their impact
on the motions of galaxies. A galaxy between structures will be caught
in a gravitational tug-of-war in which the balance of the gravitational
forces from the surrounding large-scale structures determines the
galaxy’s motion.
By using the GBT and other radio telescopes to
map the velocities of galaxies throughout our local Universe, the team
was able to define the region of space where each supercluster
dominates. “Green Bank Telescope observations have played a significant
role in the research leading to this new understanding of the limits and
relationships among a number of superclusters,” said Tully.
The
Milky Way resides in the outskirts of one such supercluster, whose
extent has for the first time been carefully mapped using these new
techniques. This so-called Laniakea Supercluster is 500 million
light-years in diameter and contains the mass of one hundred million
billion Suns spread across 100,000 galaxies.
This study also
clarifies the role of the Great Attractor, a gravitational focal point
in intergalactic space that influences the motion of our Local Group of
galaxies and other galaxy clusters.
Within the boundaries of the
Laniakea Supercluster, galaxy motions are directed inward, in the same
way that water streams follow descending paths toward a valley. The
Great Attractor region is a large flat bottom gravitational valley with a
sphere of attraction that extends across the Laniakea Supercluster.
The
name Laniakea was suggested by Nawa‘a Napoleon, an associate professor
of Hawaiian Language and chair of the Department of Languages,
Linguistics, and Literature at Kapiolani Community College, a part of
the University of Hawaii system. The name honors Polynesian navigators
who used knowledge of the heavens to voyage across the immensity of the
Pacific Ocean.
The other authors are Hélène Courtois (University
Claude Bernard Lyon 1, Lyon, France), Yehuda Hoffman (Racah Institute of
Physics, Hebrew University, Jerusalem), and Daniel Pomarède (Institute
of Research on Fundamental Laws of the Universe, CEA/Saclay, France).
The
GBT is the world's largest fully steerable radio telescope. Its
location in the National Radio Quiet Zone and the West Virginia Radio
Astronomy Zone protects the incredibly sensitive telescope from unwanted
radio interference.
The National Radio Astronomy Observatory is a
facility of the National Science Foundation, operated under cooperative
agreement by Associated Universities, Inc.
Founded in 1967, the
Institute for Astronomy at the University of Hawaii at Manoa conducts
research into galaxies, cosmology, stars, planets, and the sun. Its
faculty and staff are also involved in astronomy education, deep space
missions, and in the development and management of the observatories on
Haleakala and Maunakea. The Institute operates facilities on the islands
of Oahu, Maui, and Hawaii.
Contacts:
Mr. Charles E. Blue, NRAO Public Information Officer
(434) 296-0314; cblue@nrao.edu
Dr. R. Brent Tully
+1 808-956-8606; tully@ifa.hawaii.edu
Dr. Roy Gal
Cell: +1 301-728-8637, rgal@ifa.hawaii.edu
Ms. Talia Ogliore, Media Contact
(808) 956-4531; togliore@hawaii.edu
Mr. Charles E. Blue, NRAO Public Information Officer
(434) 296-0314; cblue@nrao.edu
Dr. R. Brent Tully
+1 808-956-8606; tully@ifa.hawaii.edu
Dr. Roy Gal
Cell: +1 301-728-8637, rgal@ifa.hawaii.edu
Ms. Talia Ogliore, Media Contact
(808) 956-4531; togliore@hawaii.edu
