Astronomy Stories
Pasadena, CA—Astronomers have believed since the 1960s that a galaxy dubbed UGC 1382 was a relatively boring, small elliptical galaxy. Ellipticals are the most common type of galaxy and lack...
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Pasadena, CA— The Astronomical Society of the Pacific (ASP) has announced that the Carnegie Observatories’ postdoctoral associate Rachael Beaton will receive the 2016 Robert J. Trumpler...
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Washington, DC— Brown dwarfs are sometimes called failed stars. They’re stars’ dim, low-mass siblings and they fade in brightness over time. They’re fascinating to astronomers...
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Pasadena, CA— Carnegie’s Allan Sandage, who died in 2010, was a tremendously influential figure in the field of astronomy. His final paper, published posthumously, focuses on unraveling a...
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Pasadena, CA— You can never predict what treasure might be hiding in your own basement. We didn’t know it a year ago, but it turns out that a 1917 image on an astronomical glass plate...
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Pasadena, CA—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...
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Take a tour with Cynthia Hunt through eight foundational images from the Carnegie Observatories' plate collection in Nautilus magazine....
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"Supernovae shape the universe we live in and there are still many unanswered questions about these explosions, even for the common ones," Ben Shappee tells The Washington Post about the...
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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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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...
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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...
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Guillermo Blanc wants to understand the processes by which galaxies form and evolve over the course of the history of the universe. He studies local galaxies in the “present day” universe as well as very distant and therefore older galaxies to observe the early epochs of galaxy...
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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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John Mulchaey is the director and the Crawford H. Greenewalt Chair of the Carnegie Observatories. He investigates groups and clusters of galaxies, elliptical galaxies, dark matter—the invisible material that makes up most of the universe—active galaxies and black holes. He is also...
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Pasadena, CA— Eta Carinae, one of the most massive stars in our Milky Way galaxy, unexpectedly increased in brightness in the 19th century. For ten years in the mid-1800s it was the second-brightest...
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Although Ross 128 b is not Earth’s twin, and there is still much scientists don’t know about its potential geologic activity, a team including Carnegie Astronomy's Johanna Teske...
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On Friday, March 23, the first blast (Big Bang Event) occurred at Las Campanas Peak in Chile, at high noon US Eastern Daylight Time. It marked the beginning of mountain leveling and site preparation...
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Explore Carnegie Science

An image of the Hubble Space Telescope floating against the background of space courtesy of NASA.
July 16, 2019

Pasadena, CA—A team of collaborators from Carnegie and the University of Chicago used red giant stars that were observed by the Hubble Space Telescope to make an entirely new measurement of how fast the universe is expanding, throwing their hats into the ring of a hotly contested debate. Their result—which falls squarely between the two previous, competing values—will be published in The Astrophysical Journal.

Nearly a century ago, Carnegie astronomer Edwin Hubble discovered that the universe has been growing continuously since it exploded into being during the Big Bang. But precisely how fast it’s moving—a value termed the Hubble constant in his

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.
May 7, 2019

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, Anthony Piro, Mark Phillips, and Josh Simon—may hold the key to solving the longstanding mystery that is the source of these violent explosions. Observations taken by the Magellan telescopes at Carnegie’s Las Campanas Observatory in Chile were crucial to detecting the emission of hydrogen that makes this supernova, called ASASSN-18tb, so distinctive.   

Their work is published in Monthly Notices of the Royal Astronomical Society.

Type Ia supernovae play a

Earth's Moon, public domain image
January 23, 2019

Pasadena, CA— “Can moons have moons?”

This simple question—asked by the four-year old son of Carnegie’s Juna Kollmeier—started it all.  Not long after this initial bedtime query,  Kollmeier was coordinating a program at the Kavli Institute for Theoretical Physics (KITP)  on the Milky Way while her one-time college classmate Sean Raymond of Université de Bordeaux was attending a parallel KITP program on the dynamics of Earth-like planets.   After discussing this very simple question at a seminar, the two joined forces to solve it.  Their findings are the basis of a paper published in Monthly Notices

December 14, 2018

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 Chile was awarded the Bernardo O’Higgins Order by the Chilean Foreign Affairs Ministry in Santiago today. The honor is in recognition “of his contribution to the development of astronomy in Chile, and for inspiring appreciation and knowledge of astronomy among students and people of all ages.”

The award is the highest civilian honor for non-Chileans. O’Higgins was one of the founders of the Chilean Republic. The award was established in 1965 to recognize

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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 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 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://cgs.obs.carnegiescience.edu/CGS/Home.html

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. 

Andrew Newman works in several areas in extragalactic astronomy, including the distribution of dark matter--the mysterious, invisible  matter that makes up most of the universe--on galaxies, the evolution of the structure and dynamics of massive early galaxies including dwarf galaxies, ellipticals and cluster. He uses tools such as gravitational lensing, stellar dynamics, and stellar population synthesis from data gathered from the Magellan, Keck, Palomar, and Hubble telescopes.

Newman received his AB in physics and mathematics from the Washington University in St. Louis, and his MS and Ph D in astrophysics from Caltech. Before becomming a staff astronomer in 2015, he was a

Scott Sheppard studies the dynamical and physical properties of small bodies in our Solar System, such as asteroids, comets, moons and trans-neptunian objects (bodies that orbit beyond Neptune).  These objects have a fossilized imprint from the formation and migration of the major planets in our Solar System, which allow us to understand how the Solar System came to be.

The major planets in our Solar System travel around the Sun in fairly circular orbits and on similar planes. However, since the discovery of wildly varying planetary systems around other stars, and given our increased understanding about small, primordial bodies in our celestial neighborhood, the notion that

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

Globular clusters are spherical systems of some 100,000  gravitationally bound stars. They are among the oldest components of our galaxy and are key to understanding the age and scale of the universe. Previous measurements of their distances have compared the characteristics of different types of stars in the solar neighborhood with the same types of stars found in the clusters. However, these measurements have systematic errors, which limit the determination of cluster ages and distances.

 Ian Thompson has a different approach to the problem: using observations of exceedingly rare Detached Eclipsing Binary stars. These systems have two separated stars orbiting each