The Sombrero galaxy (M104) is located 30 million light-years away in the constellation Virgo. Credits: NASA, ESA, CSA, STScI
The James Webb Space Telescope (JWST) once again shows off its infrared capabilities in new images of the famous Sombrero galaxy, otherwise known as Messier 104. By resolving the thick dust clouds in the outer disk and dimming the bright central star glow, JWST shows a completely new side of the famous galaxy.
In visible light, the system looks a lot like its namesake, with a broad, flat disk for an edge and a bright central core, glowing with old stars. But JWST observes the skies in infrared light, where many objects take on surprising appearances that don’t always line up with their visible-light counterparts. In particular, infrared vision can peer through dust clouds, make gas clouds suddenly visible, and dim starlight, allowing other features to shine through.
This means that for JWST’s viewing of M104, the bright core is reduced to a small spark. Without that overwhelming glow, the entire galaxy appears empty, replaced by the smooth inner disk, now visible. But this is misleading: the M104 is far from empty. In fact, it contains more stars than the Milky Way (although it is about the same size).
JWST’s predecessor, the Spitzer Space Telescope, also got an infrared view of the Sombrero, painting it more like a bull’s-eye than a hat. But Spitzer didn’t have the extraordinary resolving power of JWST; The advantage of JWST is evident in a comparison.
In the JWST image, the outer disk shows a detailed texture, like rippling clouds, representing clumps of dust. In many galaxies, such sites are often where stars form. But star formation has slowed in M104. In fact, M104 is known more for its oldest star groups: globular clusters. It has far more than its fair share, about 10 times more than the Milky Way, despite being only modestly larger.
Globular clusters are stars bound together gravitationally, resembling a sort of miniature irregular galaxy. Many of the stars in a globular structure are sisters, born from the same molecular cloud. But most globular clusters also contain intruders or multiple generations of stars. Astronomers are still unlocking the secrets of these clusters and how they contribute to the formation and evolution of galaxies.
The Sombrero Galaxy is a magnitude 8 galaxy, “only” about 30 million light-years away, making it a popular and easy target for backyard observatories, as well as NASA flagships. But despite its popularity, JWST’s strong infrared gaze can still reveal new details in this old favorite.
