Dark Energy Camera captures billions of Milky Way objects

Researchers from the Cerro Tololo Inter-American Observatory have published the results of a new survey of the plane of the Milky Way. It contains data on 3.32 billion celestial bodies located in our galaxy.

How to photograph the plane of the Milky Way

Our Milky Way contains hundreds of billions of stars, as well as regions of active star formation and clusters of dust clouds. A particularly significant concentration is observed in the area of the galactic plane, which we observe in the sky in the form of a bright band. It is there, in the spiral arms, that most of the stars and dust of our galaxy are located.

An image of the plane of the Milky Way obtained by the DECam camera during a new survey. Source: DECaPS2/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA

And although this abundance creates very beautiful views in photographs, it also significantly complicates life for astronomers. Dark tentacles of dust absorb starlight and completely obscure fainter stars, and light from diffuse nebulae interferes with any attempts to measure the brightness of individual objects. Another problem arises due to the huge number of luminaries. They may overlap in the image and make it difficult to separate individual stars from their neighbors.

Nevertheless, scientists from the Cerro Tololo Inter-American Observatory have taken up the task of photographing and cataloging objects located in the plane of our galaxy. To do this, they used a Dark Energy Camera (DECam).

Unprecedented data archive

DECam is one of the most advanced astronomical instruments of our time. The camera collects the light reflected by the 4-meter mirror of the Victor Blanco telescope and passes it through its insides, including a meter-long corrective lens. It is then captured by a grid of 62 devices with extremely sensitive CCD matrices. They allow DECam to create detailed images of faint astronomical objects.

One of the sections of the Milky Way plane photographed by DECam. Source: DECaPS2/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA

In total, astronomers have been observing the plane of the Milky Way for two years. During this time, DECam has made over 21,400 individual images. They covered 6.5% of the area of the night sky, which was equivalent to 13 thousand lunar disks (the volume of data collected during observations was 10 terabytes). Observations in the near infrared helped to look through most of the dust clouds. The researchers also used an innovative approach to data processing that allowed them to better predict the background behind each star. This helped mitigate the impact of nebulae and crowded star fields on such large astronomical images, ensuring greater accuracy of the final catalog of processed data.

An inset showing the location of the section of the Milky Way photographed by DECam. Source: DECaPS2/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA

The result of this work was a new celestial survey containing information about 3.32 billion celestial bodies located in our galaxy. This is one of the largest (and possibly one of the largest) among such archives available to astronomers. Combined with previous celestial surveys, the new data catalog will help researchers map the three-dimensional structure of stars and dust in the Milky Way with unprecedented detail.

According to https://noirlab.edu

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