NEXT-GEN ASTRONOMY


Gail Zasowski

Next-gen astronomical survey makes its first observations.

The Sloan Digital Sky Survey’s fifth generation collected its very first observations of the cosmos at 1:47 a.m. on October 24, 2020. As the world’s first all-sky time-domain spectroscopic survey, SDSS-V will provide groundbreaking insight into the formation and evolution of galaxies—like our own Milky Way—and of the supermassive black holes that lurk at their centers.

Funded primarily by member institutions, along with grants from the Alfred P. Sloan Foundation, the U.S. National Science Foundation, and the Heising-Simons Foundation, SDSS-V will focus on three primary areas of investigation, each exploring different aspects of the cosmos using different spectroscopic tools. Together these three project pillars—called “Mappers”—will observe more than six million objects in the sky, and monitor changes in more than a million of those objects over time.

The survey’s Local Volume Mapper will enhance our understanding of galaxy formation and evolution by probing the interactions between the stars that make up galaxies and the interstellar gas and dust that is dispersed between them. The Milky Way Mapper will reveal the physics of stars in our Milky Way, the diverse architectures of its star and planetary systems, and the chemical enrichment of our galaxy since the early universe. The Black Hole Mapper will measure masses and growth over cosmic time of the supermassive black holes that reside in the hearts of galaxies, and of the smaller black holes left behind when stars die.

“We are thrilled to start taking the first data for two of our three Mappers,” added SDSS-V spokesperson Gail Zasowski, an assistant professor in the University of Utah’s Department of Physics & Astronomy. “These early observations are already important for a wide range of science goals. Even these first targets provide data for studies ranging from mapping the inner regions of supermassive black holes and searching for exotic multiple-black hole systems, to studying nearby stars and their dead cores, to tracing the chemistry of potential planet-hosting stars across the Milky Way.”

A sampling of data from the first SDSS-V observations. Center: The telescope’s field-of-view, with the full Moon shown for scale. SDSS-V simultaneously observes 500 targets at a time within a circle of this size. Left: the optical-light spectrum of a quasar, a supermassive black hole at the center of a distant galaxy, which is surrounded by a disk of hot, glowing gas. The purple blob is an SDSS image of the light from this disk, the width of a human hair as seen from about 21 meters (63 feet) away. Right: The image and spectrum of a white dwarf –the left-behind core of a low-mass star (like the Sun) after the end of its life.

The newly-launched SDSS-V will continue the path-breaking tradition set by the survey’s previous generations, with a focus on the ever-changing night sky and the physical processes that drive these changes, from flickers and flares of supermassive black holes to the back-and-forth shifts of stars being orbited by distant worlds. SDSS-V will provide the spectroscopic backbone needed to achieve the full science potential of satellites like NASA’s TESS, ESA’s Gaia, and the latest all-sky X-ray mission, eROSITA.

As an international consortium, SDSS has always relied heavily on phone and digital communication. But adapting to exclusively virtual communication tactics since the beginning of the COVID-19 pandemic was a challenge, along with tracking global supply chains and laboratory availability at various university partners as they shifted in and out of lockdown during the final ramp-up to the survey’s start. Particularly inspiring were the project’s expert observing staff, who worked in even-greater-than-usual isolation to shut down, and then reopen, the survey’s mountain-top observatories.

“In a year when humanity has been challenged across the globe, I am so proud of the worldwide SDSS team for demonstrating—every day—the very best of human creativity, ingenuity, improvisation, and resilience.” said SDSS-V director Juna Kollmeier, of the Carnegie Observatories. “It has been a challenging period for SDSS and the world, but I’m happy to report that the pandemic may have slowed us, but it has not stopped us.”

Anil Seth


The University of Utah will actually operate as the data reduction center for SDSS-V, supported by the U’s Center for High Performance Computing. Joel Brownstein, a research associate professor in the Department of Physics & Astronomy, is the head of data management and archiving for SDSS-V. “As we see the first observations streaming to Utah from the mountain observatories, we are just starting to grasp the amazing potential of this ambitious data set. We are fully and proudly committed to making our results more accessible to the larger community by introducing new tools that enable a dynamic, user-driven experience.”

SDSS-V will operate out of both Apache Point Observatory in New Mexico, home of the survey’s original 2.5-meter telescope, and Carnegie’s Las Campanas Observatory in Chile, where it uses the 2.5-meter du Pont telescope.

SDSS-V’s first observations were taken in New Mexico with existing SDSS instruments, in a necessary change of plans due to the pandemic. As laboratories and workshops around the world navigate safe reopening, SDSS-V’s own suite of new innovative hardware is on the horizon—in particular, systems of automated robots to aim the fiber optic cables used to collect the light from the night sky. These robots will be installed at both observatories over the next year. New spectrographs and telescopes are also being constructed to enable the Local Volume Mapper observations.

Dr. Anil Seth, the University of Utah’s representative on the Advisory Council that oversees SDSS’s operations, highlighted the impact of the project’s open data policies and worldwide collaboration. “SDSS’s 20-year legacy has touched nearly every astronomer in the world by this point. It has become the go-to reference for astronomy textbooks on galaxies, made the most precise measurements of how our Universe is expanding, and showed us how powerful shared data can be. I look forward to see what new results SDSS V will reveal!”

For more information, please see the SDSS-V’s website at www.sdss5.org.

Adapted from a release by the Carnegie Observatories. Also published in @theU