Scientists from NASA have published a new image showing the Milky Way’s closest neighbor, the M31 galaxy, also known as the Andromeda galaxy. It was obtained by some of the most powerful telescopes in the world at different wavelengths.
The Andromeda Galaxy is the closest spiral galaxy to us. It is located at a distance of about 2.5 million light years. Astronomers use it to study the structure and evolution of our own spiral galaxy, whose study is complicated by the fact that Earth is located inside the Milky Way.
Andromeda has played an important role in many aspects of astrophysics, but especially in the discovery of dark matter. In the 1960s, astronomer Vera Rubin and her colleagues discovered that there was some invisible matter in the galaxy that affected how it and its spiral arms rotated. This unknown substance was named “dark matter.” Its nature remains one of the biggest unanswered questions in modern astrophysics.
The new image of the galaxy is a composite image obtained using some of the world’s most powerful telescopes at different wavelengths. It includes X-ray data from the Chandra and XMM-Newton observatories (red, green, and blue); ultraviolet data obtained by the GALEX telescope (blue); optical data obtained by astrophotographers using ground-based telescopes, infrared data from Spitzer, COBE, Planck, and Herschel (red, orange, and violet), as well as data from the Westerbork Synthesis Radio Telescope (red-orange).
Like all spiral galaxies observed from such a distance and at such an angle, Andromeda appears relatively flat. Its spiral arms surround a bright core, creating a disc shape similar to a large dinner plate.
Each type of radiation reveals new information about this close galactic neighbor of the Milky Way. For example, Chandra X-rays show high-energy radiation around the supermassive black hole at the center of M31, as well as many other smaller compact and dense objects scattered throughout the galaxy. However, there are no spiral arms, which makes the bright golden core and nearby stars clear and easy to study.
In radio waves, spiral arms appear red and orange, like a burning, loosely coiled rope, while the center appears black, with no discernible core. In infrared light, the outer arms appear similarly bright. Here, a white spiral ring surrounds a blue center with a small golden core. The optical image is hazy and gray, with spiral arms resembling faded rings of smoke. This is where the blackness of space is dotted with points of light, and a small bright spot shines in the center of the galaxy. Under ultraviolet light, the spiral arms appear ice blue and white, with a hazy white sphere at the center.
NASA also published a sonification of the data obtained. In the 30-second video, the layers from each telescope were separated and rotated so that they were positioned horizontally on top of each other.
As sonification moves from left to right, each type of light is matched with a different range of notes, from lower-energy radio waves to high-energy X-rays. The brightness of each source controls the volume, while the vertical position determines the pitch.
Earlier, we reported on the results of a study showing that, contrary to popular belief, the Andromeda Galaxy may not collide with the Milky Way in the future.
According to Chandra
