Astronomers have published a gigantic study of the galactic plane of the Milky Way. The new data set contains a staggering 3.32 billion celestial objects, possibly the largest catalog yet. The data for this unprecedented survey was taken with the Dark Energy Chamber, built by the US Department of Energy, at the NSF’s Cerro Tololo Inter-American Observatory in Chile, a program of NOIRLab.
The Milky Way galaxy contains hundreds of billions of stars, bright star-forming regions, and towering dark clouds of dust and gas. Imaging and cataloging these objects for study is a Herculean task, but a recently released astronomical dataset known as the Dark Energy Camera Plane Survey Second Data Release (DECaPS2) reveals a staggering number of these objects in unprecedented detail. . The DECaPS2 survey, which took two years to complete and produced more than 10 terabytes of data from 21,400 individual exposures, identified approximately 3.32 billion objects, possibly the largest catalog compiled to date.
This unprecedented collection was captured by the Dark Energy Camera (DECam) instrument on the Victor M. Blanco 4-meter Telescope at the Cerro Tololo Inter-American Observatory (CTIO), a program of NSF’s NOIRLab. CTIO is a constellation of international astronomical telescopes atop Cerro Tololo in Chile at an altitude of 2,200 meters (7,200 ft). CTIO’s elevated vantage point gives astronomers an unrivaled view of the southern celestial hemisphere, which allowed DECam to capture the southern galactic plane in such detail.
DECaPS2 is a survey of the plane of the Milky Way as seen from the southern sky taken at optical and near-infrared wavelengths. The first trove of DECaPS data was released in 2017, and with the addition of the new data release, the survey now covers 6.5% of the night sky and spans a staggering 130 degrees of longitude. While it may sound modest, this is equivalent to 13,000 times the angular area of the full moon.
The DECaPS2 dataset is available to the entire scientific community and is hosted by NOIRLab’s Astro Data Lab, which is part of the Community Science and Data Center. Interactive access to pan/zoom images within a web browser is available from Legacy Survey Viewer, World Wide Telescope and Aladin.
Most of the Milky Way’s stars and dust lie in its disk, the bright band that runs across this image, in which the spiral arms lie. While this profusion of stars and dust makes for beautiful images, it also makes the galactic plane a challenge to observe. The dark tendrils of dust seen streaking across this image absorb starlight and completely blot out fainter stars, and light from diffuse nebulae interferes with any attempt to measure the brightness of individual objects. Another challenge arises from the large number of stars, which can overlap in the image and make it difficult to separate individual stars from their neighbors.
Despite the challenges, astronomers delved deeper into the galactic plane to better understand our Milky Way. By looking at near-infrared wavelengths, they were able to look past much of the light-absorbing dust. The researchers also used an innovative data processing approach, which allowed them to better predict the background behind each star. This helped mitigate the effects of crowded nebulae and star fields in such large astro images, ensuring that the final catalog of processed data is more accurate.
«One of the main reasons for the success of DECaPS2 is that we simply targeted a region with an extraordinarily high density of stars and were careful to identify the sources that appear almost on top of each other,» said Andrew Saydjari, a graduate student at University. from Harvard, a researcher at the Center for Astrophysics, Harvard & Smithsonian, and lead author of the paper. «Doing so allowed us to produce the largest catalog ever made with a single camera, in terms of the number of objects observed.»
«When combined with images from Pan-STARRS 1, DECaPS2 completes a 360-degree panoramic view of the Milky Way’s disk and, in addition, reaches much fainter stars,» said Edward Schlafly, a researcher at the Space Telescope Science Institute managed by AURA and colleague. -author of the article describing DECaPS2 published in the Astrophysical Journal Supplement. «With this new study, we can map the three-dimensional structure of stars and dust in the Milky Way in unprecedented detail.»
«Since my work on the Sloan Digital Sky Survey two decades ago, I have been looking for a way to make better measurements over complex backgrounds,» said Douglas Finkbeiner, a professor in the Center for Astrophysics, a co-author on the paper. and principal investigator behind the project. “This work has accomplished that and more.”
«This is quite a technical feat. Imagine a group photo of over three billion people and every individual is recognizable,» says Debra Fischer, NSF division director of Astronomical Sciences. «Astronomers will be poring over this detailed portrait of more than three billion stars in the Milky Way for decades to come. This is a fantastic example of what partnerships between federal agencies can accomplish.»