Intergalactic Entity Captured for first Time in 3D
Lyman alpha blob in emerging galaxy cluster SSA22 imaged with Caltech’s Cosmic Web Imager. The arrows show the gas filaments of the IGM flowing into blob. (Christopher Martin, Robert Hurt)
For the first time, 3D images have been captured of a cosmological entity called theintergalactic medium (IGM). Until now, the structure of IGM had been theoretical.
The discovery could provide astronomers with a new understanding of galactic and intergalactic dynamics.
The images were captured with an instrument built at the California Institute of Technologycalled the Cosmic Web Imager. The device was installed on the Hale 200-inch telescope atPalomar Observatory near San Diego, California.
IGM is a network or web of thread-like formations of diffuse gases left over from the Big Bang that links all the galaxies in the universe together.
Christopher Martin, professor of physics at Caltech, created and developed the device.
“I’ve been thinking about the intergalactic medium since I was a graduate student,” he said. “Not only does it comprise most of the normal matter in the universe, it is also the medium in which galaxies form and grow.”
The first intergalactic filaments of IGM imaged by Martin’s team were within an area of space occupied by a quasar and something known as a Lyman alpha blob – considered to be one of the largest objects in the universe – which was found within a developing galaxy cluster.
Caltech’s Cosmic Web Imager installed in the Cassegrain cage of the Hale 200 inch telescope at Palomar Observatory. (Matt Matuszewski)
Martin and his colleagues observed one narrow filament that flowed into the quasar. The astronomers determined that it was about one million light-years long and might be powering the growth of the galaxy that contains the quasar. The team also found three filaments surrounding the Lyman alpha blob. Measurements indicated the diffuse gas from the filaments was pouring into the blob and affecting its dynamics.
The scientists associated with the Cosmic Web Imager say the device has already spotted one possible spiral-galaxy, three times the size of our Milky Way galaxy, that is still developing.
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