The reddest galaxies with a larger central bulge have the longest bars, that is, gigantic central columns of stars and dark matter. This is reflected in a scientific study by researchers from Europe and the US in which the Google Maps service has been used to observe the sky. The results of the most precise measurements, corresponding to 3,150 galaxies, have been published in the Monthly Notices of the Royal Astronomical Society .
The study is part of the project “Zoo of the galaxies” ( Galaxy Zoo ), a citizen science initiative in which more than 200,000 volunteers help classify one million galaxies from the images provided by the Sloan Digital Sky astronomical catalog Survey. In the case of bars, about 150 fans have registered their observations on a website created for this purpose. The page is still active, although it no longer supports any further data entry.
“This website combines the classifications of the Galaxy Zoo project with Google Maps technologies “, highlights Ben Hoyle, researcher at the Institute of Cosmos Sciences (University of Barcelona) and coordinator of the work, in statements to the SINC agency. Specifically, the team has used the Google Maps Sky interface, which allows observing the sky – in particular the galaxies – from the point of view of the Earth .
The red of the bars
“In this way we have compiled some 16,000 measurements of the bars of 5,000 galaxies, which is a hundred times more than previous samplings,” says Hoyle. “In addition to obtaining various conclusions, such as the fact that the longest bars appear in the reddest galaxies, those that are extinguishing the formation of stars.”
Within the electromagnetic spectrum,the color red comes from the oldest and coolest stars, while the blue is related to the hottest and youngest. The study also reveals that the bars are typically redder than the rest of the galaxy, implying that they have an older stellar population.
Another conclusion indicates that galaxies with a larger bulge (central agglomeration of stars) have longer bars. Furthermore, barred galaxies are more likely to have spiral arms than those without a bar.
