New Survey of the Milky Way Reveals Billions of Celestial Objects

Astronomers have released a new survey of the Milky Way that includes 3.3 billion celestial objects.

Astronomers have released a new survey of the Milky Way that includes 3.3 billion celestial objects. (NOIRLab)
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A new survey of the Milky Way has revealed a staggering 3.3 billion celestial objects. Our galaxy is teeming with hundreds of billions of stars, dark pillars of dust and gas, and stellar nurseries where stars are born. Now, astronomers have captured these wonders in unprecedented detail with the Dark Energy Camera Plane Survey, which recorded 21,400 individual exposures over two years.

The survey is the largest catalog of Milky Way objects to date and the two data releases from the program cover 6.5% of the night sky. Astronomers will be able to use the data to map the 3D structure of the galaxy’s dust and stars. “This is quite a technical feat,” said Debra Fischer, division director of astronomical sciences at the National Science Foundation. “Imagine a group photo of over three billion people and every single individual is recognizable.”

A new image of the celestial objects captured by the survey was released on Wednesday, showing stars and dust across the bright galactic disk. Dark streaks of dust obscure starlight, while the glow from star-forming regions make it difficult to spot the individual brightness of celestial objects. However, the Dark Energy Camera can see through the dust using near-infrared light and a data-processing method to reduce the obscuring effects of star-forming regions.

The data set was published in a study in the Astrophysical Journal Supplement. “One of the main reasons for the success of DECaPS2 is that we simply pointed at a region with an extraordinarily high density of stars and were careful about identifying sources that appear nearly on top of each other,” said lead study author Andrew Saydjari, a doctoral student at Harvard University and researcher at the Harvard–Smithsonian Center for Astrophysics. “Doing so allowed us to produce the largest such catalog ever from a single camera, in terms of the number of objects observed.”