Astronomy Stories
Washington, D.C.—Astronomers have discovered an extremely cool object that could have a particularly diverse history—although it is now as cool as a planet, it may have spent much of its youth as hot...
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AudioPasadena, CA—Something is amiss in the Universe. There appears to be an enormous deficit of ultraviolet light in the cosmic budget. The...
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Audio Washington, D.C.— An international team of astronomers, including five Carnegie scientists, reports the discovery of two new planets...
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Pasadena, CA—Wolf-Rayet stars are very large and very hot. Astronomers have long wondered whether Wolf-Rayet stars are the progenitors of certain types of supernovae. New work from the Palomar...
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Audio Pasadena, CA— The structures and star populations of massive galaxies appear to change as they age, but much about how these...
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Pasadena, CA— New work from a team of scientists including Carnegie’s Josh Simon analyzed the chemical elements in the faintest known galaxy, called Segue 1, and determined that it is effectively a...
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Pasadena, CA— Astronomer and instrumentation expert Stephen Shectman of the Carnegie Observatories has been elected to the National Academy of Sciences. Shectman investigates the large-scale...
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AudioPasadena, CA— Some galaxies grew up in a hurry. Most of the galaxies that have...
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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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Along with Alycia Weinberger and Ian Thompson, Alan Boss has been running the Carnegie Astrometric Planet Search (CAPS) program, which searches for extrasolar planets by the astrometric method, where the planet's presence is detected indirectly through the wobble of the host star around the...
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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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Stephen Shectman blends his celestial interests with his gift of developing novel telescope instrumentation. He investigates the large-scale structure of the galaxy distribution; searches for ancient stars that have few elements; develops astronomical instruments; and constructs large telescopes....
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With the proliferation of discoveries of planets orbiting other stars, the race is on to find habitable worlds akin to the Earth. At present, however, extrasolar planets less massive than Saturn cannot be reliably detected. Astrophysicist John Chambers models the dynamics of these newly found giant...
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Like some other Carnegie astronomers, staff associate Jeffrey Crane blends science with technology. His primary interests are instrumentation, the Milky Way and the neighboring Local Group of galaxies, in addition to extrasolar planets. In 2004, then-research associate Crane joined Steve Shectman,...
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Pasadena, CA — Using information gathered from several telescopes, a team of astronomers, including Carnegie’s Eric Murphy, searched the sky for very rarely seen dusty starburst galaxies, formed soon...
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Pasadena, CA- John Mulchaey has been appointed the new Crawford H. Greenewalt Director of the Carnegie Observatories. He is the eleventh director of the historic department, which was founded in 1904...
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Carnegie's John Mulchaey talks to NPR's Morning Edition about Edwin Hubble's work at the Mount Wilson Obeservatory and his famous Andromeda plates. Read more
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Explore Carnegie Science

Decker French
July 24, 2019

Pasadena, CA— Carnegie’s K. Decker French was recognized by the Astronomical Society of the Pacific with its Robert J. Trumpler Award, which is presented to a recent Ph.D. graduate “whose research is considered unusually important to astronomy.” French completed her doctorate at the University of Arizona Tucson in 2017 and is currently a Hubble Fellow at the Carnegie Observatories.

Her research focuses on a radio survey of the gas clouds within galaxies that have recently ended the star-forming phase of their evolution.  The lack of star formation in these galaxies has long been assumed to be caused by a depletion of the cold, dense molecular gases

Vera measuring spectra with DTM measuring engine, courtesy of Carnegie Science.
July 24, 2019

Washington, DC—The House approved yesterday a bill to name the Large Synoptic Survey Telescope in honor of late Carnegie scientist Vera Rubin, who confirmed the existence of dark matter.

Rubin received the National Medal of Science for her research on how stars orbit their galactic centers. She revealed that stars at varying distances from the center of a spiral galaxy orbit at the same speed, rather than at decreasing speeds away from the center, providing undeniable evidence that each galaxy is embedded in a halo of dark matter holding its mass together.

She died in December 2016.

“Vera demonstrated intellectual courage and a tireless commitment to

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

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The Carnegie-Spitzer-IMACS (CSI) survey, currently underway at the Magellan-Baade 6.5m telescope in Chile, has been specifically designed to characterize normal galaxies and their environments at a distance of about 4 billion years post Big Bang, expresses by astronomers as  z=1.5.

The survey selection is done using the Spitzer Space Telescope Legacy fields, which provides as close a selection by stellar mass as possible.

Using the IMACS infrared camera, the survey goal is to study galaxies down to low light magnitudes. The goal is to reduce the variance in the density of massive galaxies at these distances and times to accurately trace the evolution of the galaxy mass

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. 

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

We are all made of stardust. Almost all of the chemical elements were produced by nuclear reactions in the interiors of stars. When a star dies a fraction of the elements is released into the inter-stellar gas clouds, out of which successive generations of stars form.

 Astronomers have a basic understanding of this chemical enrichment cycle, but chemical evolution and nulceosynthesis are still not fully understood. Andrew McWilliam measures the detailed chemical composition of Red Giant stars, which are about as old as the galaxy and retain their original chemical composition.  He is seeking answer to questions such as: What are the sites of nucleosynthesis? What

Distant galaxies offer a glimpse of the universe as it was billions of years ago. Understanding how the Milky Way and other galaxies originated provides a unique perspective on the fundamental physics of cosmology, the invisible dark matter, and  repulsive force of dark energy. Patrick McCarthy uses the facilities at Carnegie’s Las Campanas Observatory to explore the early formation and evolution of galaxies. He is also director of the Giant Magellan Telescope Organization, an international consortium that is building the next generation giant telescope.  

Galaxy formation is driven by the interplay between the large-scale distribution of dark matter—that non

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

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