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Astronomers* have published the most detailed star map of a part of the Milky Way. Approximately 3.32 billion celestial objects are recorded in it. For this, 21,400 individual images and more than ten terabytes of data were collected.
The map was created over two years using the Dark Energy Camera at NSF’s Cerro Tololo Inter-American Observatory in Chile. The entire DECaPS2 survey map is publicly available in high resolution (here). It shows the Galactic disk as seen from the Southern Hemisphere. This covers 6.5 percent of the night sky.
Individual stars are difficult to identify
The researchers* captured light in the optical and near-infrared spectra. The big challenge was identifying individual objects. In this part of the Milky Way, a lot of dust absorbs starlight, making fainter objects challenging to detect. The light emanating from cosmic nebulae also makes it difficult to measure the brightness of individual objects.
In addition, there are so many stars in this region that it is difficult to tell them apart. They overlap on the image, making it difficult to determine what is in the background and foreground.
A new method for data processing
Still, the team created the giant celestial atlas to date, with 3.32 billion stars. According to study leader Andrew Saydjari of the Harvard-Smithsonian Center for Astrophysics, the reason is that they pointed the camera at a region with an exceptionally high density of stars, he says in a statement.
They used the near-infrared camera to look through much of the dust. They also used a new data processing method (study) to predict what lies behind a star. This allowed them to calculate how nebulae and dense star clusters affect the image and make the map more accurate. The results appeared in the Astrophysical Journal. In 2021, the team already published a map of the outer Milky Way.
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