Astronomy Stories
This cartoon courtesy of Anthony Piro illustrates three possibilities for the origin of the mysterious hydrogen emissions from the Type IA supernova called ASASSN-18tb that were observed by the Carnegie astronomers.
Pasadena, CA—Detection of a supernova with an unusual chemical signature by a team of astronomers led by Carnegie’s Juna Kollmeier—and including Carnegie’s Nidia Morrell...
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Over the past few years, Dr. Sheppard and his team have been performing the largest and deepest survey ever attempted of our Solar System’s fringes. In December 2018, he announced the most-...
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Earth's Moon, public domain image
Pasadena, CA— “Can moons have moons?” This simple question—asked by the four-year old son of Carnegie’s Juna...
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Pasadena, CA— Miguel Roth, director of Carnegie’s Las Campanas Observatory in Chile from 1990 to 2014 and the current representative of the Giant Magellan Telescope Organization (GMTO) in...
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An artist’s conception of a type Ia supernova exploding, courtesy of ESO.
Pasadena, CA—New work from the Carnegie Supernova Project provides the best-yet calibrations for using type Ia supernovae to measure cosmic distances, which has implications for our...
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Pan-STARRS image showing the host galaxy of the newly discovered supernova ASASSN-18bt
Pasadena, CA—A supernova discovered by an international group of astronomers including Carnegie’s Tom Holoien and...
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Pasadena, CA—Carnegie’s Anthony Piro was part of a Caltech-led team of astronomers who observed the peculiar death of a massive...
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John Graham
Washington, DC—Carnegie astronomer John Graham—who also served during different periods as both Vice President and Secretary of the American Astronomical Society—died at home in...
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The fund supports a postdoctoral fellowship in astronomy that rotates between the Carnegie Science departments of Terrestrial Magnetism in Washington, D.C., and the Observatories in Pasadena California. 
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The Carnegie Irvine Galaxy Survey is obtaining high-quality optical and near-infrared images of several hundred of the brightest galaxies in the southern hemisphere sky, at Carnegie’s Las Campanas Observatory to investigate the structural properties of galaxies. For more see    http...
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The recent discovery that the universe is expanding at an accelerating rate has profoundly affected physics. If the universe were gravity-dominated then it should be decelerating. These contrary results suggest a new form of “dark energy”—some kind of repulsive force—is...
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Looking far into space is looking back in time. Staff astronomer emeritus Alan Dressler began his career at Carnegie some years ago as a Carnegie Fellow. Today, he and colleagues use Magellan and the Hubble Space Telescope to study galaxy evolution—how galaxy structures and shapes change, the...
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Director Emeritus, George Preston has been deciphering the chemical evolution of stars in our Milky Way for a quarter of a century. He and Steve Shectman started this quest using a special technique to conduct a needle-in-the-haystack search for the few, first-generation stars, whose chemical...
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Staff member emeritus François Schweizer studies galaxy assembly and evolution by observing nearby galaxies, particularly how collisions and mergers affect their properties. His research has added to the awareness that these events are dominant processes in shaping galaxies and determining...
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Over 20 years ago, Carnegie astronomer emeritus Alan Dressler chaired the Association of Universities for Research in Astronomy (AURA) Hubble Space Telescope (HST) and Beyond Committee. The group...
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Type Ia supernovae are violent stellar explosions that shine as some of the brightest objects in the universe. But there are still many mysteries surrounding their origin—what kind of star...
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The lightest few elements in the periodic table formed minutes after the Big Bang.  Heavier chemical elements are created by stars, either from nuclear fusion in their interiors or in...
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Explore Carnegie Science

Fotografía de Yuri Beletsky, cortesía de la Carnegie Institution for Science.
April 27, 2020

Pasadena, California— El universo está lleno de miles de millones de galaxias—pero su distribución en el espacio está lejos de ser uniforme. ¿Por qué vemos tantas estructuras en el universo hoy y cómo se formó y creció todo?

Una encuesta de decenas de miles de galaxias, realizada durante 10 años utilizando el telescopio de Magallanes Baade perteneciente al Observatorio Las Campanas de Carnegie en Chile, proporcionó un enfoque para responder a este misterio fundamental. Los resultados, liderados por Daniel Kelson, de Carnegie, fueron publicados en Monthly Notices of the Royal Astronomical Society.

The Magellan telescopes at LCO by Yuri Beletsky.
April 27, 2020

Pasadena, CA— The universe is full of billions of galaxies—but their distribution across space is far from uniform. Why do we see so much structure in the universe today and how did it all form and grow? 

A 10-year survey of tens of thousands of galaxies made using the Magellan Baade Telescope at Carnegie’s Las Campanas Observatory in Chile provided a new approach to answering this fundamental mystery. The results, led by Carnegie’s Daniel Kelson, are published in Monthly Notices of the Royal Astronomical Society. 

“How do you describe the indescribable?” asks Kelson. “By taking an entirely new approach to the problem.

Caltech logo
March 17, 2020

The Carnegie Institution for Science is consolidating our California research departments into an expanded presence in Pasadena. With this move, we are building on our existing relationship with Caltech, with a goal of broadening our historic collaborations in astronomy and astrophysics and pursuing new opportunities in ecology and plant biology that will support the global fight against climate change.

This plan, which affects our research operations in Pasadena and Palo Alto, reflects Carnegie’s ongoing efforts to extend our leadership in space, Earth, and life sciences and to enhance our ability to explore new frontiers.

In selecting our Pasadena location, we

 Illustration of DS Tuc AB by M. Weiss, CfA.
March 9, 2020

Pasadena, CA— A new kind of astronomical observation helped reveal the possible evolutionary history of a baby Neptune-like exoplanet.

To study a very young planet called DS Tuc Ab, a Harvard & Smithsonian Center for Astrophysics-led team that included six Carnegie astronomers—Johanna Teske, Sharon Wang, Stephen Shectman, Paul Butler, Jeff Crane, and Ian Thompson—developed a new observational modeling tool. Their work will be published in The Astrophysical Journal Letters and represents the first time the orbital tilt of a planet younger than 45 million years—or about 1/100th the age of the Solar System—has been measured.


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The Giant Magellan Telescope will be one member of the next class of super giant earth-based telescopes that promises to revolutionize our view and understanding of the universe. It will be constructed in the Las Campanas Observatory in Chile. Commissioning of the telescope is scheduled to begin in 2021.

The GMT has a unique design that offers several advantages. It is a segmented mirror telescope that employs seven of today’s largest stiff monolith mirrors as segments. Six off-axis 8.4 meter or 27-foot segments surround a central on-axis segment, forming a single optical surface 24.5 meters, or 80 feet, in diameter with a total collecting area of 368 square meters. The GMT

The recent discovery that the universe is expanding at an accelerating rate has profoundly affected physics. If the universe were gravity-dominated then it should be decelerating. These contrary results suggest a new form of “dark energy”—some kind of repulsive force—is driving the universe. To get a grasp of dark energy, it is extremely important that scientists get the most accurate measurements possible of Type Ia supernovae. These are specific types of exploring stars with exceptional luminosity that allow astronomers to determine distances and the acceleration rate at different distances. At the moment, the reality of the accelerating universe remains

The Carnegie Hubble program is an ongoing comprehensive effort that has a goal of determining the Hubble constant, the expansion rate of the universe,  to a systematic accuracy of 2%. As part of this program, astronomers are obtaining data at the 3.6 micron wavelength using the Infrared Array Camera (IRAC) on Spitzer Space Telescope. The team has demonstrated that the mid-infrared period-luminosity relation for Cepheids, variable stars used to determine distances and the rate of the expansion,  at 3.6 microns is the most accurate means of measuring Cepheid distances to date. At 3.6 microns, it is possible to minimize the known remaining systematic uncertainties in the Cepheid

The Carnegie Irvine Galaxy Survey is obtaining high-quality optical and near-infrared images of several hundred of the brightest galaxies in the southern hemisphere sky, at Carnegie’s Las Campanas Observatory to investigate the structural properties of galaxies. For more see

Juna Kollmeier’s research is an unusual combination—she is as observationally-oriented theorist making predictions that can be compared to current and future observations. Her primary focus is on the emergence of structure in the universe. She combines cosmological hydrodynamic simulations and analytic theory to figure out how the tiny fluctuations in density that were present when the universe was only 300 thousand years old, become the galaxies and black holes that we see now, after 14 billion years of cosmic evolution. 

 She has a three-pronged approach to unravelling the mysteries of the universe. On the largest scales, she studies the intergalactic

The earliest galaxies are those that are most distant. Staff associate Dan Kelson is interested in how these ancient relics evolved. The latest generation of telescopes and advanced spectrographs—instruments that analyze light to determine properties of celestial objects—allow astronomers to accurately measure enormous numbers of distant galaxies. Kelson uses the Magellan 6.5-meter telescopes and high-resolution imaging from the Hubble Space Telescope to study distant galaxies.His observations of their masses, sizes and morphologies allow him to directly measure their stars' aging to infer their formation history. Kelson is the principal investigator of the Carnegie-

Josh Simon uses observations of nearby galaxies to study problems related to dark matter, chemical evolution, star formation, and the process of galaxy evolution.

In one area he looks at peculiarly dark galaxies. Interestingly, some galaxies are so dark they glow with the light of just a few hundred Suns. Simon and colleagues have determined that a tiny, very dim galaxy orbiting the Milky Way, called Segue 1, is the darkest galaxy ever found and has the highest dark matter density ever found. His team has also laid to rest a debate about whether Segue 1 really is a galaxy or a globular cluster—a smaller group of stars that lacks dark matter. Their findings make Segue 1 a

Rebecca Bernstein combines observational astronomy with developing new instruments and techniques to study her objects of interest. She focuses on formation and evolution of galaxies by studying the chemistry of objects called extra galactic globular clusters—old, spherical compact groups of stars that are gravitationally bound. She also studies the stellar components of clusters of galaxies and is engaged in various projects related to dark matter and dark energy—the invisible matter and repulsive force that make up most of the universe.

 Although Bernstein joined Carnegie as a staff scientist in 2012, she has had a long history of spectrographic and imaging