Astronomers have released a gargantuan survey of the galactic plane of the Milky Way. The new dataset has an impressive 3.32 billion celestial objects — arguably the largest such catalog thus far. The information for this unprecedented survey had been taken with the Dark Energy Camera, 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 vast amounts of stars, glimmering star forming regions, and towering dark clouds of dust and gas. Imaging and also cataloging these objects for study is a herculean task, but a newly released astronomical dataset known as the other data release of the Dark Energy Camera Plane Survey (DECaPS2) reveals a staggering amount of these objects in detail that is unprecedented. The DECaPS2 survey, which took two years to complete and produced more than 10 terabytes of information from 21,400 particular exposures, identified approximately 3.32 billion objects — arguably the largest such catalog compiled to date. Astronomers and the public can explore the dataset in this case.
This unprecedented collection was taken by the Dark Energy Camera (DECam) instrument on the Víctor M. Blanco 4 meter Telescope at Cerro Tololo Inter American Observatory (CTIO), a program of NSF’s NOIRLab. CTIO is a constellation of international astronomical telescopes perched atop Cerro Tololo in Chile at an altitude of 2200 meters (7200 feet). CTIO’s lofty vantage point gives astronomers an unparalleled view of the southern celestial hemisphere, which allowed DECam to record the southern Galactic plane in detail that is such.
DECaPS2 is a survey of the plane of the Milky Way as observed out of the southern sky taken at optical and near-infrared wavelengths. The first trove of data from DECaPS was launched in 2017, and with the inclusion of the new information release, the survey today covers 6.5 % of the night sky and spans an impressive 130 degrees in length. While it may seem modest, this equates to 13,000 times the angular location of the full Moon.
The DECaPS2 dataset can be obtained on the entire scientific community and it is hosted by NOIRLab’s Astro Data Lab, that is an element of the Community Science and Data Center. Interactive access to the imaging with panning/zooming inside of a web browser is available from the Legacy Survey Viewer, the world Wide Aladin and Telescope.
Most of the stars and dust in the Milky Way are located in its disk — the brilliant band stretching out across this particular image — where the spiral arms lie. While this profusion of stars and dust makes for beautiful images, additionally, it makes the Galactic plane challenging to look at. The dim tendrils of dust seen threading through this image absorb blot and starlight out fainter stars entirely, and the light from diffuse nebulae interferes with any efforts to measure the brightness of specific items. An additional challenge arises from the large number of stars, which may overlap in the image and make it difficult to disentangle specific stars from their neighbors.
Despite the difficulties, astronomers delved into the Galactic plane to obtain a better understanding of the Milky Way of ours. By observing at near infrared wavelengths, they were able to peer past much of the light-absorbing dust. The researchers likewise used an innovative data-processing approach, which allowed them to better anticipate the background behind every star. This helped to mitigate the effects of nebulae and crowded star fields on such large astronomical images, ensuring that the last catalog of processed information is more accurate.
“One of the primary reasons because of the achievements of DECaPS2 is that we simply pointed at a region with an extraordinarily high density of stars and also were careful about identifying energy sources that appear nearly in addition to each other,” said Andrew Saydjari, a graduate pupil at Harvard University, researcher in the Center for Astrophysics | Harvard & lead author and Smithsonian of the paper. “Doing so allowed us to produce the biggest that catalog perhaps from an individual camera, in terminology of the number of items observed.”
“When coupled with images from Pan STARRS 1, DECaPS2 completes a 360-degree panoramic view of the Milky Way ‘s disk and additionally reaches much fainter stars,” said Edward Schlafly, a researcher in the AURA managed Space Telescope Science Institute along with a co-author of the paper describing DECaPS2 posted in the Astrophysical Journal Supplement. “With this new survey, we can map the three-dimensional structure of the Milky Way’s stars and dust in unprecedented detail.”
“Since the work of mine on the Sloan Digital Sky Survey 2 decades ago, I’ve been searching for a way to make much better measurements on top of complex backgrounds,” said Douglas Finkbeiner, a professor at the Center for Astrophysics, co author of the newspaper, and primary investigator behind the project. “This work has achieved that and more!”
“This is rather a technical feat. Imagine a group photo of over three billion folks and every single individual is recognizable!” says Debra Fischer, division director of Astronomical Sciences at NSF. “Astronomers is poring over this detailed portrait of more than three billion stars in the Milky Way for decades to come. This’s an excellent example of what partnerships across federal agencies are able to achieve.”
DECam was originally built to perform the Dark Energy Survey, which was done by the Department of Energy as well as the US National Science Foundation between 2013 and 2019.