ALPINE sky survey program finds rotating disk-shaped galaxies in the early universe

The ALPINE program has announced that using combined observations from a host of telescopes it has determined that there may have been large numbers of rotating disc-shaped galaxies in the early universe. Data that the team used for their observations came from the ALMA observatory along with observations from other telescopes, including the W. M. Keck Observatory in Hawaii and NASA's Hubble and Spitzer space telescopes.

The team says this is the first multi-wavelength study from ultraviolet to radio waves of distant galaxies that existed between 1 billion and 1.5 billion years after the big bang. One of the ALPINE project's key functions is to use ALMA to observe for the signature of an ion known as C⁺, which is a positively charged form of carbon.

When the ultraviolet light from a newborn star hits clouds of dust, it creates C⁺ atoms. Scientists can measure the signature of that atom or "emission line" in galaxies to see how they are rotating. As the gas containing C⁺ spins towards us, the light signature shifts to bluer wavelengths. As it spins away, the light shifts to redder wavelengths.

The team made C⁺ measurements of 118 remote galaxies to create a catalog of rotation speeds, and other features like gas density and the number of stars formed. The survey found that rotating mangled galaxies in the process of merging, along with seemingly perfectly smooth spiral-shaped galaxies. About 15 percent of the galaxies observed had smooth, ordered rotation expected of a spiral galaxy.

The team notes that the galaxies may not be spirals, but rotating disks with clumps of material. Future observations with more advanced space telescopes will be made to determine the structure of the galaxies.