Our Peculiar Motion Away from the Local Void (Forwarded)

Institute for Astronomy
University of Hawai'i
Director's Office
2680 Woodlawn Drive, Honolulu, Hawaii 96822
(808) 956-8566 Fax: (808) 946-3467
Website: http://www.ifa.hawaii.edu

CONTACT:
Dr. R. Brent Tully (808) 956-8606 or Mrs. Karen Rehbock (808) 956-6829

FOR RELEASE: 9:30 a.m. Hawaiian Standard Time, May 28, 2007

Our Peculiar Motion Away from the Local Void

Much Ado About Nothing

Our Milky Way galaxy lies at the edge of a huge void and is being repulsed
by the void at high speed. This observation provides astronomers with a
fundamental insight into how dark matter is distributed and into the
process of galaxy formation. Brent Tully of the University of Hawaii is
discussing this discovery at the meeting of the American Astronomical
Society in Honolulu, Hawaii. His collaborators in this research are Helene
Courtois, Dale Kocevski, and Luca Rizzi, all at the University of Hawaii
during the period of research, Ed Shaya and Alan Peel at the University of
Maryland, and Igor Karachentsev of the Special Astrophysical Observatory
in Russia.

Two decades ago, Brent Tully and his collaborator Richard Fisher (National
Radio Astronomy Observatory, Charlottesville, Virginia) noted that our
galaxy lives adjacent a vast empty region that they called the 'Local
Void'. Today, thanks to the contributions of many astronomers around the
world, there is information on the distribution of hundreds of thousands
of galaxies and an increasingly detailed knowledge of the rich tapestry in
the distribution of galaxies. Galaxies collect along filaments and in
clusters, at places where the filaments intersect. Elsewhere there are
empty regions called voids. Our galaxy resides in a filament that bounds a
void. We call this filament the 'Local Sheet'.

It has also been known for two decades that our Milky Way galaxy is
traveling through intergalactic space at high speed. The Cosmic Microwave
Background (CMB) is radiation that comes to us in all directions from the
time when the universe was a hot plasma, 3 hundred thousand years after
the Big Bang. A tiny one part in a hundred systematic variation in
frequency of the peak of the CMB radiation is taken to be a Doppler shift
caused by our motion with respect to the ensemble of all other matter.
Some of the components of our motion have been known for a long time. The
Earth orbits the Sun once a year and the Sun orbits the center of the
Milky Way Galaxy every 250 million years. We also have known that our
galaxy is being pulled toward neighboring concentrations of matter,
particularly our nearest giant neighbor, the Andromeda Galaxy, at a
distance of 2 million light-years and the nearest rich cluster of
thousands of galaxies, the Virgo Cluster, at 55 million light-years. It
has also become clear that there are very long-range forces pulling on us.
We have a motion in a direction toward two huge concentrations of galaxies
that happen by chance to line up, one behind the other, at distances of
200 and 600 million light-years. The relative importance of these two
attractors has remained a detail in dispute among astronomers.

Yet until now part of our motion inferred from the variation in the CMB
remained unexplained. It is in a direction aligned with the flattened disk
of our galaxy and there was the possibility that something important was
being hidden by the veil of obscuring dust clouds in the plane of the
Milky Way. However, radiation at X-ray, infrared, and radio wavelengths
are not blocked. Years of observing by many astronomers have failed to
reveal anything important.

Now, another kind of observation has resolved the mystery. Astronomers
have been measuring the distances to galaxies with precision techniques.
With accurate distances it is possible to distinguish between the motions
of galaxies due to the general expansion of the universe and the local
deviant motions caused by the way matter is clumped, with its consequent
gravitational effects. It is found that galaxies are flowing in streams,
with coherent flows caused by large attractors far away and eddies caused
by modest attractors nearby. The influences on our motion discussed above
have been confirmed. In addition, features of the local streaming pattern
reveal the source of the additional component.

The critical new information comes from observations of relatively nearby
galaxies with Hubble Space Telescope. Accurate distances to galaxies are
provided by measuring the luminosities of the brightest old stars that lie
on what is known as the Red Giant Branch. These stars have well
established properties. The accurate distances give a detailed map of the
flow pattern of nearby galaxies and reveal several remarkable things.
First, the direction of our motion with respect to the nearest several
thousand galaxies is well defined. Second, all the galaxies within 15
million light years, within our Local Sheet, are moving together. Third,
this motion is NOT shared by galaxies just beyond our Local Sheet and, in
fact, we are moving on a collision course toward the nearest adjacent
filament, the Leo Spur (it will be at least 10 billion years before the
Local Sheet and the Leo Spur pancake together).

These patterns reveal the cause: the Local Void. Whereas concentrations of
matter pull, a void pushes! If an object is surrounded uniformly by matter
in all directions, except for one sector in which there is nothing, then
the absence of a pull is a push away from that sector. The effect can be
astonishingly large. Our velocity away from the Local Void is 600,000
miles per hour.

To generate such a large velocity, the void must be very large and very
empty. The current standard model of the universe with dark matter and
dark energy does allow for voids that are as large as we infer for the
Local Void, but it is impressive that we should live next to such a large
feature. More importantly for our theoretical understanding, we conclude
that the void is really empty. Only a small fraction of the matter of the
universe is in a visible form, so it is not a given that an apparently
empty region is truly empty. However, the large push we are getting from
the Local Void is convincing evidence that it really is empty!

The determination of distances from the properties of Red Giant Branch
stars is based on observations by the authors and others made with Hubble
Space Telescope. Distance determinations of many more galaxies have been
made by a variety of methods, in part by the authors. This research has
been supported by the National Science Foundation.

The Institute for Astronomy at the University of Hawaii 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
Mauna Kea.

Established in 1907 and fully accredited by the Western Association of
Schools and Colleges, the University of Hawaii is the state's sole public
system of higher education. The UH System provides an array of
undergraduate, graduate, and professional degrees and community programs
on 10 campuses and through educational, training, and research centers
across the state. UH enrolls more than 50,000 students from Hawaii, the
U.S. mainland, and around the world.

IMAGE CAPTION:
[http://www.ifa.hawaii.edu/info/press..._aas07-630.jpg
(180KB)]
Distribution of galaxies in the region around our Milky Way in
supergalactic coordinates. Each little dot represents a galaxy of
typically 100 billion stars. The colors indicate the relative motions of
galaxies with accurately measured distances, with shades of green and blue
indicating motions toward us and shades of yellow to red indicating
motions away from us. Our nearest neighbors have only small relative
motions (represented by yellows and greens) as seen best in the exploded
view of the right panel. The observed pattern of velocities is explained
as follows. We, along with all these nearest neighbors, are moving
together toward the lower right corner of the figures. The result is that
all the galaxies in the lower right appear to be moving toward us and all
the galaxies in the upper left appear to be moving away -- but it is us
and our neighbors that are moving. Our motion is represented by the orange
arrow. We now understand that there are two main causes for this motion.
The concentration of objects at the right of the figures is the Virgo
Cluster and its mass of quadrillion (10**15) times the Sun causes an
attraction indicated by the blue vector in the exploded panel. The red
vector in this panel is what is left over and this represents our motion
of 600,000 miles per hour away from the Local Void. In detail, the Local
Void may consist of several components, identified in the left panel as
the Local Void and the North and South extensions.

On Jun 7, 3:27 am, Andrew Yee wrote:
Institute for Astronomy
University of Hawai'i
Director's Office
2680 Woodlawn Drive, Honolulu, Hawaii 96822
(808) 956-8566 Fax: (808) 946-3467
Website:http://www.ifa.hawaii.edu

CONTACT:
Dr. R. Brent Tully (808) 956-8606 or Mrs. Karen Rehbock (808) 956-6829

FOR RELEASE: 9:30 a.m. Hawaiian Standard Time, May 28, 2007

Our Peculiar Motion Away from the Local Void

Much Ado About Nothing

Our Milky Way galaxy lies at the edge of a huge void and is being repulsed
by the void at high speed. This observation provides astronomers with a
fundamental insight into how dark matter is distributed and into the
process of galaxy formation. Brent Tully of the University of Hawaii is
discussing this discovery at the meeting of the American Astronomical
Society in Honolulu, Hawaii. His collaborators in this research are Helene
Courtois, Dale Kocevski, and Luca Rizzi, all at the University of Hawaii
during the period of research, Ed Shaya and Alan Peel at the University of
Maryland, and Igor Karachentsev of the Special Astrophysical Observatory
in Russia.

Two decades ago, Brent Tully and his collaborator Richard Fisher (National
Radio Astronomy Observatory, Charlottesville, Virginia) noted that our
galaxy lives adjacent a vast empty region that they called the 'Local
Void'. Today, thanks to the contributions of many astronomers around the
world, there is information on the distribution of hundreds of thousands
of galaxies and an increasingly detailed knowledge of the rich tapestry in
the distribution of galaxies. Galaxies collect along filaments and in
clusters, at places where the filaments intersect. Elsewhere there are
empty regions called voids. Our galaxy resides in a filament that bounds a
void. We call this filament the 'Local Sheet'.

It has also been known for two decades that our Milky Way galaxy is
traveling through intergalactic space at high speed. The Cosmic Microwave
Background (CMB) is radiation that comes to us in all directions from the
time when the universe was a hot plasma, 3 hundred thousand years after
the Big Bang. A tiny one part in a hundred systematic variation in
frequency of the peak of the CMB radiation is taken to be a Doppler shift
caused by our motion with respect to the ensemble of all other matter.
Some of the components of our motion have been known for a long time. The
Earth orbits the Sun once a year and the Sun orbits the center of the
Milky Way Galaxy every 250 million years. We also have known that our
galaxy is being pulled toward neighboring concentrations of matter,
particularly our nearest giant neighbor, the Andromeda Galaxy, at a
distance of 2 million light-years and the nearest rich cluster of
thousands of galaxies, the Virgo Cluster, at 55 million light-years. It
has also become clear that there are very long-range forces pulling on us.
We have a motion in a direction toward two huge concentrations of galaxies
that happen by chance to line up, one behind the other, at distances of
200 and 600 million light-years. The relative importance of these two
attractors has remained a detail in dispute among astronomers.

Yet until now part of our motion inferred from the variation in the CMB
remained unexplained. It is in a direction aligned with the flattened disk
of our galaxy and there was the possibility that something important was
being hidden by the veil of obscuring dust clouds in the plane of the
Milky Way. However, radiation at X-ray, infrared, and radio wavelengths
are not blocked. Years of observing by many astronomers have failed to
reveal anything important.

Now, another kind of observation has resolved the mystery. Astronomers
have been measuring the distances to galaxies with precision techniques.
With accurate distances it is possible to distinguish between the motions
of galaxies due to the general expansion of the universe and the local
deviant motions caused by the way matter is clumped, with its consequent
gravitational effects. It is found that galaxies are flowing in streams,
with coherent flows caused by large attractors far away and eddies caused
by modest attractors nearby. The influences on our motion discussed above
have been confirmed. In addition, features of the local streaming pattern
reveal the source of the additional component.

The critical new information comes from observations of relatively nearby
galaxies with Hubble Space Telescope. Accurate distances to galaxies are
provided by measuring the luminosities of the brightest old stars that lie
on what is known as the Red Giant Branch. These stars have well
established properties. The accurate distances give a detailed map of the
flow pattern of nearby galaxies and reveal several remarkable things.
First, the direction of our motion with respect to the nearest several
thousand galaxies is well defined. Second, all the galaxies within 15
million light years, within our Local Sheet, are moving together. Third,
this motion is NOT shared by galaxies just beyond our Local Sheet and, in
fact, we are moving on a collision course toward the nearest adjacent
filament, the Leo Spur (it will be at least 10 billion years before the
Local Sheet and the Leo Spur pancake together).

These patterns reveal the cause: the Local Void. Whereas concentrations of
matter pull, a void pushes! If an object is surrounded uniformly by matter
in all directions, except for one sector in which there is nothing, then
the absence of a pull is a push away from that sector. The effect can be
astonishingly large. Our velocity away from the Local Void is 600,000
miles per hour.

To generate such a large velocity, the void must be very large and very
empty. The current standard model of the universe with dark matter and
dark energy does allow for voids that are as large as we infer for the
Local Void, but it is impressive that we should live next to such a large
feature. More importantly for our theoretical understanding, we conclude
that the void is really empty. Only a small fraction of the matter of the
universe is in a visible form, so it is not a given that an apparently
empty region is truly empty. However, the large push we are getting from
the Local Void is convincing evidence that it really is empty!


What about possibility of existence "negative energy" or "negative
mass"
(this new "negative mass" type ("right neutrinos" etc.) would interact
only
gravitationally with our familiar ordinary positive mass) inside that
huge void,
would that give also required large push ?

Problem: Lonely galaxies are observed also inside of these huge voids
(or
are we sure that these observed lonely galaxies are not located
behind these huge voids ?)

This new "negative mass" type would possible be observable in WMAP's
pictures about temperature distribution of cosmic background
radiation (two different types spots, one for positive mass type
and one for "negative mass" type). Different mass types would have
been separated to different space areas due this push force since the
beginning of big bang (these two would then have totally different
evolution paths) ?

Hannu

The determination of distances from the properties of Red Giant Branch
stars is based on observations by the authors and others made with Hubble
Space Telescope. Distance determinations of many more galaxies have been
made by a variety of methods, in part by the authors. This research has
been supported by the National Science Foundation.

The Institute for Astronomy at the University of Hawaii 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
Mauna Kea.

Established in 1907 and fully accredited by the Western Association of
Schools and Colleges, the University of Hawaii is the state's sole public
system of higher education. The UH System provides an array of
undergraduate, graduate, and professional degrees and community programs
on 10 campuses and through educational, training, and research centers
across the state. UH enrolls more than 50,000 students from Hawaii, the
U.S. mainland, and around the world.

IMAGE CAPTION:
[http://www.ifa.hawaii.edu/info/press..._aas07-630.jpg
(180KB)]
Distribution of galaxies in the region around our Milky Way in
supergalactic coordinates. Each little dot represents a galaxy of
typically 100 billion stars. The colors indicate the relative motions of
galaxies with accurately measured distances, with shades of green and blue
indicating motions toward us and shades of yellow to red indicating
motions away from us. Our nearest neighbors have only small relative
motions (represented by yellows and greens) as seen best in the exploded
view of the right panel. The observed pattern of velocities is explained
as follows. We, along with all these nearest neighbors, are moving
together toward the lower right corner of the figures. The result is that
all the galaxies in the lower right appear to be moving toward us and all
the galaxies in the upper left appear to be moving away -- but it is us
and our neighbors that are moving. Our motion is represented by the orange
arrow. We now understand that there are two main causes for this motion.
The concentration of objects at the right of the figures is the Virgo
Cluster and its mass of quadrillion (10**15) times the Sun causes an
attraction indicated by the blue vector in the exploded panel. The red
vector in this panel is what is left over and this represents our motion
of 600,000 miles per hour away from the Local Void. In detail, the Local
Void may consist of several components, identified in the left panel as
the Local Void and the North and South extensions.