Published on September 19th, 2013 | by Martha Kent0
3D Map of the Universe: Large Scale Structures
An international team of scientists led by astronomers at the Kyoto University, University of Tokyo and the University of Oxford released the first version of the first 3D map of the Universe. The map is a part of the FastSound project that aims to map far away distant galaxies and could help determine the unexplained accelerating expansion of the Universe.
The project is about mapping Galaxies of our Universe at nine billion light years away. Using the new Fiber Multi-Object Spectrograph (FMOS) of the Subaru Telescope, the team of astronomers have created a 3D map that includes 1,100 galaxies. This it a large-scale structure of the Universe as it was nine billion years ago (see the image above).
The FastSound project includes this 3D map that depicts the Universe approximately 4.7 billion years after the Big Bang. The 3D map spans across 600 milions light years in angular direction and 2 billion light in the radial direction. The colors of galaxies seen in the map indicate their star formation rate (ie the total mass of stars in the galaxy that are formed every year). The background hue represents the density of the background galaxies and the distribution of mass (which is dominated by the presence of so-called “dark matter”, which it is believed to represent about 30% of total energy in the Universe).
The FastSound project is one of the strategic programs of the Subaru Telescope. The observations began in March 2012 and it will continue until spring 2014. Although the research conducted so far using 3D maps of the Universe were interested in nearby universe (eg, in 2006, Sloan Digital Sky Survey project examined an area up to 5 billion light-years away), FastSound project is distinguished by producing a 3D map of the distant universe that covers a larger area, which is more than 10 billion light-years away.
FMOS is a powerful wide field spectrograph which allows near-infrared spectroscopy and can scan more than 100 items at a time. The extremely wide field observation of the spectrograph is possible due to the combination of infrared and optical domains obtained by collecting light using the 8.2ma primary mirror of the Subaru telescope.
The final 3D map of distant Universe serves the main scientific objective of the project: the precise measurement of the movement of Galaxies and the determination of the growth rate of cosmic structures at large scale. This is also a test of the general theory of relativity enunciated by Einstein. Although scientists know that the expansion of the Universe is accelerating, they do not know the reason for this phenomenon, so it became one of the most important questions in contemporary astronomy and physics. An unidentified form of energy named “dark energy” seems to uniformly fill the entire universe and it represents about 70% of the mass and energy of the universe. Apparently, this dark energy causes accelerating expansion. As an alternative to this hypothesis lies the theory of gravity in a cosmological scale that may differ from that of general relativity (which is the theory that describes gravity and space-time). The comparison between the 3D map of our younger Universe and the predictions of general relativity could finally reveal the cause for the mysterious accelerating expansion of the current Universe.
image source: FastSound project, www.naoj.org