Camera captures Southern Pinwheel galaxy in glorious detail

Astronomy enthusiasts might wonder why a camera called the Dark Energy Camera (DECam) would be used to image a single spiral galaxy. DECam has indeed already completed its main work, since the instrument was used to complete the Dark Energy Survey, which took place from 2013 to 2019. Like many people, rather than enjoying a quiet retirement, DECam keep busy. Members of the astronomical community can request time to use it, and the data collected is processed and made public, thanks to the Astro Data Archive of the Community Science and Data Center (CSDC) program at NSF’s NOIRLab. The continuous operation of DECam also makes lavishly detailed footage like this possible.

Messier 83, or the Southern Windmill, is located in the southern constellation Hydra and is an obvious target for a beautiful astronomical picture. It is oriented so that it is almost entirely front-facing when viewed from Earth, which means we can observe its spiral structure in fantastic detail. The galaxy is about 15 million light years away, making it a neighbor in astronomical terms. It’s about 50,000 light years in diameter, so it’s a bit small compared to our own Milky Way, which is 100,000 to 200,000 light years in diameter. In other respects, however, the Southern Windmill probably gives a good approximation of how our Milky Way would look like a distant alien civilization.

Six different filters were used on DECam to create this spectacular new sight of classic beauty. Filters allow astronomers to select the wavelengths of light in which they want to see the sky. This is crucial for scientific observations, when astronomers need very specific information about an object, but it also creates colorful images like this. Observing celestial objects, such as the Southern Windmill, with several different filters means that different details can be spotted. For example, the dark tendrils that curl across the galaxy are actually tracks of dust, blocking light. In contrast, the bright red spots in clusters are caused by hot, glowing hydrogen gas (which identifies them as centers of star formation). Dust trails and dynamic ionized gas have different temperatures, and are therefore visible in different wavelengths. Filters allow you to observe the two separately and then combine them into a single complex image. A total of 163 DECam exposures, with a combined total exposure time of over 11.3 hours, made it possible to create this portrait of Messier 83.

https://www.youtube.com/watch?v=TfxrMOVsyTI

Yet these observations weren’t just meant to create a pretty picture. They are helping to prepare the next observations of the Vera C. Rubin Observatory, a future program of NOIRLab. In ten years of operation, from 2023, the Rubin Observatory will carry out an unprecedented optical survey of the visible sky called the Legacy Survey of Space and Time (LSST). “The Messier 83 observations are part of an ongoing program to produce an atlas of time varying phenomena in neighboring southern galaxies for the Legacy Survey of Space and Time at the Rubin Observatory,” said Monika Soraisam, investigator for DECam’s observations on Messier 83. “We are generating multi-colored light curves of stars in this galaxy, which will be used to tame the onslaught of expected LSST alerts using state-of-the-art software infrastructure such as that of NOIRLab. ANTARES alert-broker. ”

Built by the US Department of Energy (DOE), DECam is mounted on the 4-meter Víctor M. Blanco telescope at CTIO in Chile. DECam is a powerful instrument that uses 74 highly sensitive Charge Coupled Devices (CCDs) to capture images. CCDs are the same devices used to take pictures in everyday cell phones. Of course, DECam’s CCD sensors are much larger and have been specially designed to collect very faint red light from distant galaxies. This capability was crucial to DECam’s original purpose, the Dark Energy Survey. This ambitious investigation probed one of the Universe’s most fundamental questions: Why is our Universe not only expanding, but expanding at an accelerating rate? For six years, DECam has studied the sky, imagining the most distant galaxies to collect more data to allow astronomers to further study our accelerating Universe. Taking great pictures like this should look a lot easier for DECam.

“Although DECam has achieved its original goal of completing the Dark Energy Investigation, it continues to be a valuable resource for the astronomical community, capturing panoramic views of objects like Messier 83 that delight the senses and advance progress. our understanding of the Universe, ”said Chris Davis, program director for NOIRLab at the National Science Foundation.

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Provided by NOIRlab