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Astronomers map vast emptiness in our cosmic neighborhood



  Astronomers map vast void in our cosmic neighborhood
A smoothed rendering of the structure surrounding the local void. Our Milky Way is at the origin of the red-green-blue orientation arrows (each 200 million light-years long). We are at the boundary between a large, low-density cavity and the high density Jungfrau Cluster. Picture credits: R. Brent Tully

An astronomer from the Institute of Astronomy at the University of Hawaii (IfA) and an international team published a new study revealing more of the vast cosmic structure of our galaxy galaxy.

The universe is a tapestry of galaxy communities and huge cavities. In a recent study reported in The Astrophysical Journal Brent Tully's team uses the same tools from a previous study to map the size and shape of a vast empty region called a local void and that limits the galaxy galaxy. By observing galaxy movements, they deduce the distribution of the mass responsible for that motion and construct three-dimensional maps of our local universe.

Galaxies not only move with the total extent of the universe, but also respond to the gravitational tug of their neighbors and regions with much mass. As a result, they move towards the densest areas and away from low mass regions ̵

1; the cavities.

Although we live in a cosmic metropolis, Tully and Richard Fisher stated as early as 1987 that our Milky Way galaxy is also located in the edge of a vast empty region they called the local emptiness. The existence of the local void has been widely accepted, but has remained poorly studied because it is located behind the center of our galaxy and therefore, in our view, is very obscured.


Now, Tully and his team have measured the motions of 18,000 galaxies In the Compendium Cosmicflows-3 of Galaxy Distances, create a cosmographic map that highlights the boundary between the collection of matter and the absence of matter that defines the edge of the local void , In 2014, they used the same technique to identify the full scale of our home supercluster of over one hundred thousand galaxies, naming it Laniakea, which in Hawaiian means "immense sky."

Astronomers have been trying to identify themselves for 30 years Why do the Milky Way, our nearest android neighbor Andromeda, and their smaller neighbors deviate from the total universe by more than 600 km / s? The new study shows that about half of this movement is "local" from the combination of a move from the massive nearby Jungfrau Cluster and our involvement in the expansion of the local void as it becomes increasingly emptier.

Representations of the void can be seen in a video (below) and alternatively in an interactive model (below). The interactive model allows a viewer to pan, zoom, rotate and pause / activate the temporal evolution of movement along the orbits. The orbits are displayed in a frame of reference that cancels the entire expansion of the universe. What we are seeing are the deviations from the cosmic expansion caused by the interactions of local gravitational sources.


Galaxy orbits the local supercluster


Further information:
Cosmicflows-3: Cosmography of the Local Void, The Astrophysical Journal (2019). DOI: 10.3847 / 1538-4357 / ab2597

Provided by
University of Hawaii in Manoa




Quote :
Astronomers map huge emptiness in our cosmic neighborhood (2019, July 22)
retrieved on July 22, 2019
from https://phys.org/news/2019-07-astronomers-vast-void-cosmic-neighborhood.html

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