At Last, the Milky Way Gets a Better Close Up
After two years In terms of data acquisition and numerical processing, a team of astronomers has captured a literal snapshot of the cosmic scale. It’s filled with stellar goodness: Image shows reddish-brown dust clouds clustered along the center line of our Milky Way with more than 3 billion rays—nearly all stars , a faint neighboring galaxy here or there.
The project, based at the Harvard-Smithsonian Center for Astrophysics, is called the Dark Energy Camera Plane Survey, and aims to index objects that lie in the plane of our galaxy. In January, researchers published their second data release IN Additional astrophysics journal series, making it the largest catalog or index of stars ever collected by a single instrument, and one of the few instances where we turned the camera toward the middle of our galaxy. It’s a selfie in space, if you will.
But while the stars are performers, the other point of this survey is to capture the elusive substance floating between them: dust. Because the dust mask glows, it distorts our view of the universe. Knowing how much is out there could help astronomers filter its effects from their data and more accurately assess the chemistry and positions of the stars. Over the next decade, scientists will use this catalog to perfect maps of galactic dust, track ancient star systems, and study the formation and structure of our Milky Way.
For the survey, the team reused the Dark Energy Camera, or DECam, an optical instrument at the Cerro Tololo Inter-American Observatory in Chile that was originally built to study faint objects in far from the galactic plane. “We used this instrument built for cosmology, and we pointed it at the center of the celestial plane,” said Eddie Schlafly, an astronomer at the Space Telescope Science Institute. galaxy, where there are tons of stars, dust and gas. and fog.” The goal, he said, is to address as many individual light sources as possible.
That’s a pretty high order: Most astronomers don’t observe the galactic plane because it’s notoriously difficult to photograph. “The Milky Way is a spiral galaxy. So most of its stars are in a flatbread,” said Andrew Saydjari, a physics graduate student at Harvard University who led the survey. Unfortunately for observers on Earth, we sit right in the middle of that pancake. It is easy to see above or below our plane in that disk, where the stellar cloud is thin. But looking at the center of the galaxy, or looking back to the outer edge, is difficult because the view is so crowded. “A lot of stars can appear as if they were on top of each other,” says Saydjari.
Other things around the galactic center don’t help. For example, some gases are hot enough to emit their own photons of a color similar to the light of stars. And dust can make celestial objects look dimmer and redder than they really are. Both of these can skew astronomers’ measurements of the luminosity and position of stars.