Study: Distant galactic halos more common than astronomers expected

KINGSTON, Ontario, Oct. 13 (UPI) -- A new survey of distant spiral galaxies suggests galactic halos are more common than astronomers previously thought.

Using the Karl G. Jansky Very Large Array, a team of researchers at Canada's Queens University analyzed 35 spiral galaxies from an edge-on perspective, looking horizontally across the galactic discs. The galaxies ranged in distance from 11 million to 137 million light-years from Earth.

The survey -- and their improved imaging technology -- revealed a number of halos of cosmic rays and magnetic fields, stretching out above and below the edge-on galaxies.

"We knew before that some halos existed, but, using the full power of the upgraded VLA and the full power of some advanced image-processing techniques, we found that these halos are much more common among spiral galaxies than we had realized," Queen's researcher Judith Irwin said in a press release.

Most of the matter in -- and most of the light emanating from -- spiral galaxies is concentrated in a horizontally oriented disc. The light pollution has made it difficult for astronomers to study vertically oriented phenomena.

The new survey, detailed in paper published online this week in the Astronomical Journal, opens up a range of new research possibilities.

"Studying these halos with radio telescopes can give us valuable information about a wide range of phenomena, including the rate of star formation within the disk, the winds from exploding stars, and the nature and origin of the galaxies' magnetic fields," said lead study author Theresa Wiegert, a postdoctoral student at Queens.

To exhibit the vertical reach of spiral galaxies, researcher superimposed all 35 galaxies on top of one another, each scaled to stretch the same length.

The result is, Irwin said, "a spectacular image showing that cosmic rays and magnetic fields not only permeate the galaxy disk itself, but extend far above and below the disk."