The famous Sombrero Galaxy now appears as more than a wide-brimmed hat floating in deep outer space.
New images from the Cerro Tololo Inter-American Observatory in Chile reveal a gigantic halo surrounding the galaxy, stretching three times its width. Already considered one of the largest objects in the Virgo Galaxy Cluster, the galaxy's expansive glow is roughly 150,000 light-years wide.
The pictures come from the Dark Energy Camera, an instrument mounted on the U.S. National Science Foundation's Victor M. Blanco 4-meter Telescope. Though the camera was built for a study that ended in 2019, it continues to aid astronomers, providing new insights for even the most photographed cosmic targets.
"This may be the first time the halo has been captured with this level of detail and at this large a scale," according to NOIRLab, a program of the National Science Foundation.
Discovered in 1781 by the French comet hunter Pierre Méchain, the Sombrero is a nearly edge-on spiral galaxy about 30 million light-years away from Earth in the Virgo constellation. Méchain was an associate of renowned astronomer Charles Messier, but the object was only scribbled onto Messier's personal copy of the Messier Catalogue.
It wasn't until two other astronomers — William Herschel and Camille Flammarion — observed the galaxy that it was formally added to the catalog in 1921. Back then, it was merely known as Messier 104.
The intriguing galaxy later earned its nickname for its uncanny resemblance to a Mexican hat. Its central bulge looks like the crown and a dark dust trail brings to mind a wide brim. Though the object can't be seen with the naked eye, many amateur astronomers enjoy gazing at it through binoculars and small backyard telescopes.
But different observatories tend to bring out different features in the galaxy. The James Webb Space Telescope homed in on the Sombrero about 1.5 years ago, and showed it in a different light — literally. From Webb's infrared perspective, the hazy bulge was decapitated, revealing instead a smooth core.
Researchers are interested in the galaxy for its roughly 2,000 globular clusters containing hundreds of thousands of old stars. Though the stars within them are of similar ages, their masses and characteristics vary.
The new images also highlight a stellar stream emerging from the south side of the galaxy. The feature is faint but vast.
"The halo and the stellar stream are populated with stars that have been torn from their home galaxies," according to NOIRLab, "hinting at a past galactic merger between the Sombrero and a smaller satellite galaxy."
