Astronomy Stories
Pasadena, CA— A team of astronomers, led by Wendy Freedman, director of the Carnegie Observatories, have used NASA's Spitzer Space Telescope...
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Pasadena, CA— With the combined power of NASA's Spitzer and Hubble Space Telescopes, as well as a cosmic magnification effect, a team of astronomers, including Carnegie’s Daniel Kelson, have spotted...
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Washington, D.C.—Type Ia supernovae are violent stellar explosions. Observations of their brightness are used to determine distances in the universe and have shown scientists that the universe is...
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Pasadena, CA—Type Ia supernovae are important stellar phenomena, used to measure the expansion of the universe. But astronomers know embarrassingly little about the stars they come from and how the...
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Pasadena, CA—The Big Bang produced lots of hydrogen and helium and a smidgen of lithium. All heavier elements found on the periodic table have been produced by stars over the last 13.7 billion years...
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Pasadena, CA – The board of directors of the Giant Magellan Telescope Organization (GMTO) has informed the National Science Foundation (NSF) that they will not participate in an upcoming funding...
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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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Pasadena, CA--Astronomers have begun to blast 3 million cubic feet of rock from a mountaintop in the Chilean Andes to make room for what will be the world’s largest telescope when completed near the...
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The Earthbound Planet Search Program has discovered hundreds of planets orbiting nearby stars using telescopes at Lick Observatory, Keck Observatory, the Anglo-Australian Observatory, Carnegie's Las Campanas Observatory, and the ESO Paranal Observatory.  Our multi-national team has been...
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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 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...
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Alycia Weinberger wants to understand how planets form, so she observes young stars in our galaxy and their disks, from which planets are born. She also looks for and studies planetary systems. Studying disks surrounding nearby stars help us determine the necessary conditions for planet formation....
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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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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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Washington, D.C.—Astronomers have discovered a new super-Earth in the habitable zone, where liquid water and a stable atmosphere could reside, around the nearby star HD 40307. It is one of three new...
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Pasadena, CA— A team of astronomers including Carnegie’s Ian Thompson have managed to improve the measurement of the distance to our nearest neighbor galaxy and, in the process, refine an...
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How far away is that galaxy?  Our entire understanding of the Universe is based on knowing the distances to other galaxies, yet this seemingly-simple question turns out to be fiendishly...
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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 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

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 center of mass of the system. With over eight years of CAPSCam data, they are beginning to see likely true astrometric wobbles beginning to appear. The CAPSCam planet search effort is on the verge of yielding a harvest of astrometrically discovered planets, as well as accurate parallactic distances to many young stars and M dwarfs. For more see

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-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

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

Some 40 thousand tons of extraterrestrial material fall on Earth every year. This cosmic debris provides cosmochemist Conel Alexander with information about the formation of the Solar System, our galaxy, and perhaps the origin of life.

Alexander studies meteorites to determine what went on before and during the formation of our Solar System. Meteorites are fragments of asteroids—small bodies that originated between Mars and Jupiter—and are likely the last remnants of objects that gave rise to the terrestrial planets. He is particularly interested in the analysis of chondrules, millimeter-size spherical objects that are the dominant constituent of the most primitive

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, Ian Thompson, and the Carnegie team to design the Planet Finder Spectrograph (PFS), now installed and operational on the Magellan Clay telescope.

Radial velocities are the speeds and directions of stars moving away from or toward the Earth.  Extrasolar planet hunters use them to detect the telltale wobbles of stars that are gravitationally tugged by orbiting planets. Astronomical

Leopoldo Infante became the director of the Las Campanas Observatory on July 31, 2017.

Since 2009, Infante has been the founder and director of the Centre for Astro-Engineering at the Chilean university. He joined PUC as an assistant professor in 1990 and has been a full professor since 2006. He was one of the creators of PUC’s Department of Astronomy and Astrophysics, and served as its director from 2000 to 2006. He also established the Chilean Astronomical Society (SOCHIAS) and served as its president from 2009 to 2010.

Infante received his B.Sc. in physics at PUC. He then acquired a MSc. and Ph.D. in physics and astronomy from the University of Victoria in