SPACE/COSMOS
In ancient stellar nurseries, some stars are born of fluffy clouds
Observations of the Small Magellanic Cloud: insights into star formation in early-universe-like environments
Kyushu University
image:
A far infrared image of the Small Magellanic Cloud as observed by the European Space Agency's (ESA) Herschel Space Observatory. Circles indicate the positions observed by the ALMA telescope, with the corresponding enlarged image of the observed molecular cloud from radio waves emitted by carbon monoxide. The enlarged pictures framed in yellow indicate filamentary structures. The pictures in the blue frame indicate fluffy shapes.
view moreCredit: ALMA (ESO/NAOJ/NRAO), Tokuda et al., ESA/Herschel
Fukuoka, Japan—How are stars born, and has it always been this way?
Stars form in regions of space known as stellar nurseries, where high concentrations of gas and dust coalesce to form a baby star. Also called molecular clouds, these regions of space can be massive, spanning hundreds of light-years and forming thousands of stars. And while we know much about the life cycle of a star thanks to advances in technology and observational tools, precise details remain obscure. For example, did stars form this way in the early universe?
Publishing in The Astrophysical Journal, researchers from Kyushu University, in collaboration with Osaka Metropolitan University, have found that in the early universe, some stars may have formed in “fluffy” molecular clouds. The results were obtained from observations of the Small Magellanic Cloud and may provide a new perspective on star formation throughout the history of the universe.
In our Milky Way galaxy, the molecular clouds that facilitate star formation have an elongated “filamentary” structure about 0.3 light-years wide. Astronomers believe that our Solar System was formed in the same way, where a large filamentary molecular cloud broke apart to form a stellar egg, also called a molecular cloud core. Over hundreds of thousands of years, gravity would attract gases and matter into the cores to create a star.
“Even today our understanding of star formation is still developing, comprehending how stars formed in the earlier universe is even more challenging,” explains Kazuki Tokuda, a Post‐doctoral Fellow at Kyushu University’s Faculty of Science and first author of the study. “The early universe was quite different from today, mostly populated by hydrogen and helium. Heavier elements formed later in high-mass stars. We can’t go back in time to study star formation in the early universe, but we can observe parts of the universe with environments similar to the early universe.”
The team set their sights on the Small Magellanic Cloud (SMC), a dwarf galaxy near the Milky Way about 20,000 light-years from Earth. The SMC contains only about one-fifth of the heavy elements of the Milky Way, making it very close to the cosmic environment of the early universe, about 10 billion years ago. However, the spatial resolution for observing the molecular clouds in the SMC was often insufficient, and it was unclear whether the same filamentary structure could be seen at all.
Fortunately, the ALMA radio telescope in Chile was powerful enough to capture higher-resolution images of the SMC and determine the presence or absence of filamentary molecular clouds.
“In total, we collected and analyzed data from 17 molecular clouds. Each of these molecular clouds had growing baby stars 20 times the mass of our Sun,” continues Tokuda. “We found that about 60% of the molecular clouds we observed had a filamentary structure with a width of about 0.3 light-years, but the remaining 40% had a ‘fluffy’ shape. Furthermore, the temperature inside the filamentary molecular clouds was higher than that of the fluffy molecular clouds.”
This temperature difference between filamentary and fluffy clouds is likely due to how long ago the cloud was formed. Initially, all clouds were filamentary with high temperatures due to the clouds colliding with each other. When the temperature is high, the turbulence in the molecular cloud is weak. But as the temperature of the cloud drops, the kinetic energy of the incoming gas causes more turbulence and smoothens the filamentary structure, resulting in the fluffy cloud.
If the molecular cloud retains its filamentary shape, it is more likely to break up along its long “string” and form many stars like our Sun, a low-mass star with planetary systems. On the other hand, if the filamentary structure cannot be maintained, it may be difficult for such stars to emerge.
“This study indicates that the environment, such as an adequate supply of heavy elements, is crucial for maintaining a filamentary structure and may play an important role in the formation of planetary systems,” concludes Tokuda. “In the future, it will be important to compare our results with observations of molecular clouds in heavy-element-rich environments, including the Milky Way galaxy. Such studies should provide new insights into the formation and temporal evolution of molecular clouds and the universe.”
Example of a filamentary (left) and fluffy (right) molecular cloud in the Small Magellanic Cloud captured by the ALMA telescope
The radio waves emitted by carbon monoxide molecules are shown in color. The brighter the color, the stronger the radio emission. The crosses in the middle indicate the presence of giant baby stars. The left figure shows a molecular cloud with a filamentary structure, and the right figure shows an example of a molecular cloud with a fluffy shape. Scale bar: one light-year.
Credit
ALMA (ESO/NAOJ/NRAO), Tokuda et al.
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For more information about this research, see "ALMA 0.1 pc View of Molecular Clouds Associated with High-Mass Protostellar Systems in the Small Magellanic Cloud: Are Low-Metallicity Clouds Filamentary or Not?" Kazuki Tokuda, Yuri Kunitoshi, Sarolta Zahorecz, Kei E. I. Tanaka, Itsuki Murakoso, Naoto Harada, Masato I. N. Kobayashi, Tsuyoshi Inoue, Marta Sewilo, Ayu Konishi, Takashi Shimonishi, Yichen Zhang, Yasuo Fukui, Akiko Kawamura, Toshikazu Onishi, and, Masahiro N. Machida The Astrophysical Journal https://doi.org/10.3847/1538-4357/ada5f8
About Kyushu University
Founded in 1911, Kyushu University is one of Japan's leading research-oriented institutes of higher education, consistently ranking as one of the top ten Japanese universities in the Times Higher Education World University Rankings and the QS World Rankings. The university is one of the seven national universities in Japan, located in Fukuoka, on the island of Kyushu—the most southwestern of Japan’s four main islands with a population and land size slightly larger than Belgium. Kyushu U’s multiple campuses—home to around 19,000 students and 8000 faculty and staff—are located around Fukuoka City, a coastal metropolis that is frequently ranked among the world's most livable cities and historically known as Japan's gateway to Asia. Through its VISION 2030, Kyushu U will “drive social change with integrative knowledge.” By fusing the spectrum of knowledge, from the humanities and arts to engineering and medical sciences, Kyushu U will strengthen its research in the key areas of decarbonization, medicine and health, and environment and food, to tackle society’s most pressing issues.
Journal
The Astrophysical Journal
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
ALMA 0.1 pc View of Molecular Clouds Associated with High-Mass Protostellar Systems in the Small Magellanic Cloud: Are Low-Metallicity Clouds Filamentary or Not?
Article Publication Date
20-Feb-2025
Unlocking the future of satellite navigation with smart techniques
Aerospace Information Research Institute, Chinese Academy of Sciences
image:
RMSE of the stepwise and centralized dynamic OD. (a) RMSE of the Stepwise OD (b) RMSE of centralized OD.
view moreCredit: Satellite Navigation
A new study reveals advanced methods for improving orbit determination (OD) of large constellations of Low Earth Orbit (LEO) satellites, utilizing Global Navigation Satellite System (GNSS) observations and inter-satellite ranging. These innovations promise to significantly boost the accuracy and computational efficiency essential for satellite communication, remote sensing, and navigation augmentation.
Large constellations of Low Earth Orbit (LEO) satellites are integral to modern satellite communication, remote sensing, and navigation systems. However, tracking the orbits of these satellites poses a significant challenge due to their vast numbers and the need for high-precision data over long periods. Ground-based tracking stations are limited in their ability to handle such vast constellations, while spaceborne Global Navigation Satellite System (GNSS) receivers offer a promising solution. Unfortunately, existing methods still struggle with computational efficiency and accuracy, necessitating the development of more advanced techniques.
Published (DOI: 10.1186/s43020-025-00160-1) on February 10, 2025, in Satellite Navigation, a new study from the Xi'an Research Institute of Surveying and Mapping and the State Key Laboratory of Spatial Datum presents stepwise autonomous orbit determination (OD) methods for large LEO constellations. By combining GNSS observations with inter-satellite ranging, the research significantly enhances both the accuracy and efficiency of OD—an essential component of satellite functionality.
The study introduces three pioneering autonomous OD strategies. The first method integrates GNSS data with inter-satellite link (ISL) range measurements to refine orbit parameters. The second method utilizes ISL ranges as constraints, improving accuracy without adding computational load. The third strategy adapts the covariance matrix of orbit predictions dynamically, addressing errors caused by abnormal dynamic model information. These approaches begin with initial orbit parameter estimation via spaceborne GNSS observations, followed by refinements using ISL range data. The adaptive approach stands out by adjusting the covariance matrix based on an adaptive factor, which controls dynamic model errors. Simulations demonstrate substantial improvements, with the root mean square error (RMSE) of position estimates dropping to as low as 11.34 cm when combining dynamic models with ISL ranges. Moreover, the ability to parallelize the estimation process for individual satellites reduces computational burden, offering a scalable solution for managing large constellations.
Dr. Yuanxi Yang, a leading expert in satellite navigation and one of the study's authors, underscores the importance of these advancements: "Our stepwise autonomous OD methods provide a practical solution to the computational and accuracy challenges faced by large LEO constellations. By integrating GNSS observations and ISL ranging, we achieve higher precision and efficiency, paving the way for more robust satellite operations."
The implications of this research are far-reaching. The enhanced OD techniques provide a scalable solution that will improve the operational efficiency of large LEO constellations, ensuring more accurate satellite communication, remote sensing, and navigation augmentation. As satellite constellations grow in size and complexity, these methods offer a reliable framework for maintaining precise orbit control—unlocking vast potential for global navigation, environmental monitoring, and beyond.
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DOI
Original Source URL
https://doi.org/10.1186/s43020-025-00160-1
Funding information
This work was funded by the National Natural Science Foundation of China (Grant No. 42388102; No. 41931076).
About Satellite Navigation
Satellite Navigation (E-ISSN: 2662-1363; ISSN: 2662-9291) is the official journal of Aerospace Information Research Institute, Chinese Academy of Sciences. The journal aims to report innovative ideas, new results or progress on the theoretical techniques and applications of satellite navigation. The journal welcomes original articles, reviews and commentaries.
Journal
Satellite Navigation
Subject of Research
Not applicable
Article Title
Stepwise autonomous orbit determination of large LEO constellations by GNSS observations with partial inter-satellite ranging
Article Publication Date
19-Feb-2025
DESI uncovers 300 new intermediate-mass black holes plus 2500 new active black holes in dwarf galaxies
The Dark Energy Spectroscopic Instrument discovers a treasure trove of active black holes in dwarf galaxies and reveals that surprisingly few are of intermediate mass
Association of Universities for Research in Astronomy (AURA)
image:
This artist’s illustration depicts a dwarf galaxy that hosts an active galactic nucleus — an actively feeding black hole. In the background are many other dwarf galaxies hosting active black holes, as well as a variety of other types of galaxies hosting intermediate-mass black holes.
view moreCredit: NOIRLab/NSF/AURA/J. da Silva/M. Zamani
Using early data from the Dark Energy Spectroscopic Instrument (DESI), a team of scientists have compiled the largest sample ever of dwarf galaxies that host an actively feeding black hole, as well as the most extensive collection of intermediate-mass black hole candidates to date. This dual achievement not only expands scientists’ understanding of the black hole population in the Universe, but also sets the stage for further explorations regarding the formation of the first black holes to form in the Universe and their role in galaxy evolution.
DESI is a state-of-the-art instrument that can capture light from 5000 galaxies simultaneously. It was constructed, and is operated, with funding from the Department of Energy (DOE) Office of Science. DESI is mounted on the U.S. National Science Foundation (NSF) Nicholas U. Mayall 4-meter Telescope at the NSF Kitt Peak National Observatory, a Program of NSF NOIRLab. The program is now in its fourth of five years surveying the sky and is set to observe roughly 40 million galaxies and quasars by the time the project ends.
The DESI project is an international collaboration of more than 900 researchers from over 70 institutions around the world and is managed by DOE’s Lawrence Berkeley National Laboratory (Berkeley Lab).
With DESI’s early data [1], which include survey validation and 20% of the first year of operations, the team, led by University of Utah postdoctoral researcher Ragadeepika Pucha, was able to obtain an unprecedented dataset that includes the spectra of 410,000 galaxies [2], including roughly 115,000 dwarf galaxies — small, diffuse galaxies containing thousands to several billions of stars and very little gas. This extensive set would allow Pucha and her team to explore the complex interplay between black hole evolution and dwarf galaxy evolution.
While astrophysicists are fairly confident that all massive galaxies, like our Milky Way, host black holes at their centers, the picture becomes unclear as you move toward the low-mass end of the spectrum. Finding black holes is a challenge in itself, but identifying them in dwarf galaxies is even more difficult, owing to their small sizes and the limited ability of our current instruments to resolve the regions close to these objects. An actively feeding black hole, however, is easier to spot.
“When a black hole at the center of a galaxy starts feeding, it unleashes a tremendous amount of energy into its surroundings, transforming into what we call an active galactic nucleus,” says Pucha. “This dramatic activity serves as a beacon, allowing us to identify hidden black holes in these small galaxies.”
From their search the team identified an astonishing 2500 candidate dwarf galaxies hosting an active galactic nucleus (AGN) — the largest sample ever discovered. The significantly higher fraction of dwarf galaxies hosting an AGN (2%) relative to previous studies (about 0.5%) is an exciting result and suggests scientists have been missing a substantial number of low-mass, undiscovered black holes.
In a separate search through the DESI data, the team identified 300 intermediate-mass black hole candidates — the most extensive collection to date. Most black holes are either lightweight (less than 100 times the mass of our Sun) or supermassive (more than one million times the mass of our Sun). The black holes in between the two extremes are poorly understood, but are theorized to be the relics of the very first black holes formed in the early Universe, and the seeds of the supermassive black holes that lie at the center of large galaxies today. Yet they remain elusive, with only around 100–150 intermediate-mass black hole candidates known until now. With the large population discovered by DESI, scientists now have a powerful new dataset to use to study these cosmic enigmas.
“The technological design of DESI was important for this project, particularly its small fiber size, which allowed us to better zoom in on the center of galaxies and identify the subtle signatures of active black holes,” says Stephanie Juneau, associate astronomer at NSF NOIRLab and co-author of the paper. “With other fiber spectrographs with larger fibers, more starlight from the galaxy's outskirts comes in and dilutes the signals we’re searching for. This explains why we managed to find a higher fraction of active black holes in this work relative to previous efforts.”
Typically, black holes found in dwarf galaxies are expected to be within the intermediate-mass regime. But intriguingly, only 70 of the newly discovered intermediate-mass black hole candidates overlap with dwarf AGN candidates. This adds another layer of excitement to the findings and raises questions about black hole formation and evolution within galaxies.
“For example, is there any relationship between the mechanisms of black hole formation and the types of galaxies they inhabit?” Pucha said. “Our wealth of new candidates will help us delve deeper into these mysteries, enriching our understanding of black holes and their pivotal role in galaxy evolution.”
Notes
[1] DESI early data is available as files via the DESI collaboration and as searchable databases of catalogs and spectra via the Astro Data Lab and SPARCL at the Community Science and Data Center, a Program of NSF NOIRLab.
[2] DESI's early data contain nearly 3.5 million unique galaxy spectra. The sample used in this work was selected based on redshift (distance) and accurate detection of emission lines.
More information
This research was presented in a paper titled “Tripling the Census of Dwarf AGN Candidates Using DESI Early Data” to appear in The Astrophysical Journal. DOI: 10.3847/1538-4357/adb1dd
The team is composed of Ragadeepika Pucha (University of Utah, University of Arizona), S. Juneau (NSF NOIRLab), Arjun Dey (NSF NOIRLab), M. Siudek (Institute of Space Sciences (ICE-CSIC), Instituto de Astrof´ısica de Canarias), M. Mezcua (ICE-CSIC, Institut d’Estudis Espacials de Catalunya (IEEC)), J. Moustakas (Siena College), S. BenZvi (University of Rochester), K. Hailine (University of Arizona), R. Hviding (Max Planck Institute for Astronomy, University of Arizona), Yao-Yuan Mao (University of Utah), D. M. Alexander (Durham University), R. Alfarsy (University of Portsmouth), C. Circosta (European Space Agency (ESA), University College London), Wei-Jian Guo (National Astronomical Observatories, Chinese Academy of Sciences), V. Manwadkar (Stanford University, SLAC National Accelerator Laboratory), P. Martini (The Ohio State University), B. A. Weaver (NSF NOIRLab), J. Aguilar (Lawrence Berkeley National Laboratory), S. Ahlen (Boston University), D. Bianchi (Università degli Studi di Milano), D. Brooks (University College London), R. Canning (University of Portsmouth), T. Claybaugh (Lawrence Berkeley National Laboratory) K. Dawson (University of Utah), A. de la Macorra (Universidad Nacional Autónoma de México), Biprateep Dey (University of Toronto, University
of Pittsburgh), P. Doel (University College London), A. Font-Ribera (University College London, The Barcelona Institute of Science and Technology), J. E. Forero-Romero (Universidad de los Andes), E. Gaztañaga (IEEC, University of Portsmouth, ICE-CSIC), S. Gontcho A Gontcho (Lawrence Berkeley National Laboratory), G. Gutierrez (Fermi National Accelerator Laboratory), K. Honscheid (The Ohio State University), R. Kehoe (Southern Methodist University), S. E. Koposov (University of Edinburgh, University of Cambridge), A. Lambert (Lawrence Berkeley National Laboratory), M. Landriau (Lawrence Berkeley National Laboratory), L. Le Guillou (Sorbonne Université, CNRS/IN2P3), A. Meisner (NSF NOIRLab), R. Miquel (Institució Catalana de Recerca i Estudis Avançats, The Barcelona Institute of Science and Technology), F. Prada (Instituto de Astrofísica de Andalucía (CSIC)), G. Rossi (Sejong University), E. Sanchez (CIEMAT), D. Schlegel (Lawrence Berkeley National Laboratory) M. Schubnell (University of Michigan), H. Seo (Ohio University), D. Sprayberry (NSF NOIRLab), G. Tarlé (University of Michigan), and H. Zou (National Astronomical Observatories, Chinese Academy of Sciences).
This research is supported by the Director, Office of Science, Office of High Energy Physics of the U.S. Department of Energy, and by the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility; additional support for DESI is provided by the U.S. National Science Foundation, Division of Astronomical Sciences; the Science and Technology Facilities Council of the United Kingdom; the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; the French Alternative Energies and Atomic Energy Commission (CEA); the National Council of Humanities, Science and Technology of Mexico (CONAHCYT); the Ministry of Science, Innovation and Universities of Spain (MICIU/AEI/10.13039/501100011033), and by the DESI Member Institutions. The authors are honored to be permitted to conduct scientific research on I’oligam Du’ag (Kitt Peak), a mountain with particular significance to the Tohono O’odham Nation.
Current DESI Member Institutions include: Aix-Marseille University; Argonne National Laboratory; Barcelona-Madrid Regional Participation Group; Brookhaven National Laboratory; Boston University; Brazil Regional Participation Group; Carnegie Mellon University; CEA-IRFU, Saclay; China Participation Group; Cornell University; Durham University; École Polytechnique Fédérale de Lausanne; Eidgenössische Technische Hochschule, Zürich; Fermi National Accelerator Laboratory; Granada-Madrid-Tenerife Regional Participation Group; Harvard University; Kansas State University; Korea Astronomy and Space Science Institute; Korea Institute for Advanced Study; Lawrence Berkeley National Laboratory; Laboratoire de Physique Nucléaire et de Hautes Energies; Ludwig Maximilians University; Max Planck Institute; Mexico Regional Participation Group; National Taiwan University; New York University; NSF’s National Optical-Infrared Astronomy Research Laboratory; Ohio University; Perimeter Institute; Shanghai Jiao Tong University; Siena College; SLAC National Accelerator Laboratory; Southern Methodist University; Swinburne University; The Ohio State University; Universidad de los Andes; University of Arizona; University of Barcelona; University of California, Berkeley; University of California, Irvine; University of California, Santa Cruz; University College London; University of Florida; University of Michigan at Ann Arbor; University of Pennsylvania; University of Pittsburgh; University of Portsmouth; University of Queensland; University of Rochester; University of Toronto; University of Utah; University of Waterloo; University of Wyoming; University of Zurich; UK Regional Participation Group; Yale University. For more information, visit desi.lbl.gov.
Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit http://www.lbl.gov.
DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
NSF NOIRLab, the U.S. National Science Foundation center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), NSF Kitt Peak National Observatory (KPNO), NSF Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and NSF–DOE Vera C. Rubin Observatory (in cooperation with DOE’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona.
The scientific community is honored to have the opportunity to conduct astronomical research on I’oligam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence of I’oligam Du’ag (Kitt Peak) to the Tohono O’odham Nation, and Maunakea to the Kanaka Maoli (Native Hawaiians) community.
The National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 to promote the progress of science. NSF supports basic research and people to create knowledge that transforms the future. Please refer to www.nsf.gov.
Established in 2007 by Mark Heising and Elizabeth Simons, the Heising-Simons Foundation (www.heisingsimons.org) is dedicated to advancing sustainable solutions in the environment, supporting groundbreaking research in science, and enhancing the education of children.
The Gordon and Betty Moore Foundation, established in 2000, seeks to advance environmental conservation, patient care and scientific research. The Foundation’s Science Program aims to make a significant impact on the development of provocative, transformative scientific research, and increase knowledge in emerging fields. For more information, visit www.moore.org.
The Science and Technology Facilities Council (STFC) of the United Kingdom coordinates research on some of the most significant challenges facing society, such as future energy needs, monitoring and understanding climate change, and global security. It offers grants and support in particle physics, astronomy and nuclear physics, visit www.stfc.ac.uk
This mosaic shows a series of images featuring candidate dwarf galaxies hosting an active galactic nucleus, captured with the Subaru Telescope’s Hyper Suprime-Cam.
This mosaic shows a series of images featuring intermediate-mass black hole candidates, arranged in increasing order of stellar mass, captured with the Subaru Telescope’s Hyper Suprime-Cam.
This mosaic shows a series of images featuring intermediate-mass black hole candidates, arranged in increasing order of stellar mass, captured with the Subaru Telescope’s Hyper Suprime-Cam.
Credit
Legacy Surveys/D. Lang (Perimeter Institute)/NAOJ/HSC Collaboration/D. de Martin (NSF NOIRLab) & M. Zamani (NSF NOIRLab)
This scatter plot shows the number of candidate dwarf galaxies hosting active galactic nuclei (AGN) from previous surveys as compared with the number of new dwarf galaxy AGN candidates discovered by the Dark Energy Spectroscopic Instrument (DESI). This plot is adapted from Figure 5 in the paper titled “Tripling the Census of Dwarf AGN Candidates Using DESI Early Data,” appearing in The Astrophysical Journal.
Credit
NOIRLab/NSF/AURA/R. Pucha/J. Pollard
Within the Dark Energy Spectroscopic Instrument’s early data, scientists have uncovered the largest samples ever of intermediate-mass black holes and dwarf galaxies hosting an active black hole, more than tripling the existing census of both. These large statistical samples will allow for more in-depth studies of the dynamics between dwarf galaxy evolution and black hole growth, and open up vast discovery potential surrounding the evolution of the Universe’s earliest black holes.
Links
- Read the paper: Tripling the Census of Dwarf AGN Candidates Using DESI Early Data
- Visit the Dark Energy Spectroscopic Instrument webpage
- Images of DESI
- Videos of DESI
- Images of Nicholas U. Mayall 4-meter telescope
- Videos of Nicholas U. Mayall 4-meter telescope
- Check out other NOIRLab Science Releases
Journal
The Astrophysical Journal
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