In shape, the celestial behemoths resemble other spiral galaxies, such as our very own Milky Way. But in size, the Milky Way might as well be a fish swimming next to a blue whale.
Dubbed “super spirals” by researchers from the California Institute of Technology (Caltech) and the Univ. of California, Los Angeles (UCLA), these galaxies can shine up to 14 times brighter than the Milky Way, be 10 times more massive, and four times the width, according to NASA’s Jet Propulsion Laboratory.
The super spirals are the subject of a research paper recently published in The Astrophysical Journal.
The research team used data from the NASA/IPAC Extragalactic Database (NED), which provided the team with “a unique fusion of multi-wavelength photometry from Galaxy Evolution Explorer (GALEX), Sloan Digital Sky Survey (SDSS), and the 2-Micron All-Sky Survey (2MASS), among others,” according to the research paper.
In total, the team used a sample of approximately 800,000 galaxies, but focused on 53 that showcased the spiral shape. The closest super spiral, according to the researchers, was around 1.2 billion light-years away.
“While super spirals have similar structure to less luminous spiral galaxies, they are impressive in the vastness of their scale,” the researchers wrote.
According to NASA, their brightness indicates that the galaxies boast a star formation rate 30 times greater than the typical galaxy.
A previous theory dictated that this shouldn’t happen. Spiral galaxy growth is usually spurred by the galaxy bringing in gas from surrounding space. At a certain point though, the gas accumulates too quickly, and a process known as quenching prevents further star formation, according to NASA.
“It’s as if we have just discovered a new land animal stomping around that is the size of an elephant but had shockingly gone unnoticed by zoologists,” said lead author Patrick Ogle in a statement.
Interestingly, four of the 53 galaxies contained two nuclei, a usual indication of two galaxies merging together. Typically, the collision would result in an elliptical galaxy. However, the researchers posit that a collision between gas-rich spiral galaxies may result in a super spiral galaxy.