Astronomy Stories
Carnegie Science, Carnegie Institution, Carnegie Institution for Science, Sloan Digital Sky Survey, SDSS-IV
National Harbor, MD—Astronomers with the Sloan Digital Sky Survey (SDSS) have learned that the chemical composition of a star can exert unexpected influence on...
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Pasadena, CA— A team of astronomers led by Carnegie’s Eduardo Bañados used Carnegie’s Magellan telescopes to discover the most-distant supermassive black hole ever observed....
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SN2015J, a very bright and peculiar supernova, which initially did not have a certain home, now has received its happy ending.  Discovered on April 27, 2015, by the Siding Springs Observatory in...
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Carnegie Science, Carnegie Institution, Carnegie Institution for Science, Robin Dienel, SDSS-V, Sloan Digital Sky Survey
Pasadena, CA— The next generation of the Sloan Digital Sky Survey (SDSS-V), directed by Carnegie’s Juna Kollmeier, will move forward with mapping the entire sky following a $16 million...
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Carnegie Science, Carnegie Institution, Carnegie Institution for Science, European Southern Observatory, ESO/M. Kornmesser
Pasadena, CA— It’s the celestial equivalent of a horror movie villain—a star that wouldn’t stay dead. An international team of astronomers including Carnegie’s Nick...
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Carnegie Science, Carnegie Institution, Carnegie Institution for Science, Giant Magellan Telescope Organization, GMTO
Pasadena, CA—The Giant Magellan Telescope Organization (GMTO) today announced that it has initiated the casting of the fifth of seven mirrors that will form the heart of the Giant Magellan...
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Carnegie Science, Carnegie Institution, Carnegie Institution for Science,
Washington, DC— On August 17, a team of four Carnegie astronomers provided the first-ever glimpse of two neutron stars colliding, opening the door to a new era of astronomy.   Along with...
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Carnegie Science, Carnegie Institution, Carnegie Institution for Science, Benjamin Shappee, ASAS-SN
Pasadena, CA— In 2015, a star called KIC 8462852 caused quite a stir in and beyond the astronomy community due to a series of rapid, unexplained dimming events seen while it was being monitored...
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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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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 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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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...
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Staff astronomer emeritus Eric Persson headed a group that develops and uses telescope instrumentation to exploit new near-infrared (IR) imaging array detectors. The team built a wide-field survey camera for the du Pont 2.5-meter telescope at Carnegie’s Las Campanas Observatory in Chile...
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Gwen Rudie
Gwen Rudie studies the chemical and physical properties of very distant galaxies and their surrounding gas in order to further our understanding of the processes that are central to the formation and development of galaxies. Critical to this research is our ability to trace the raw...
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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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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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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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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

An artist’s conception of a type Ia supernova exploding, courtesy of ESO.
December 11, 2018

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 understanding of how fast the universe is expanding and the role dark energy may play in driving this process. Led by Carnegie astronomer Chris Burns, the team’s findings are published in The Astrophysical Journal.  

Type Ia supernovae are fantastically bright stellar phenomena. They are violent explosions of a white dwarf—the crystalline remnant of a star that has exhausted its nuclear fuel—which is part of a binary system with another star.

In addition to being

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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 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 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

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 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-

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. Young disks contain the raw materials for building planets and the ultimate architecture of planetary systems depends on how these raw materials are distributed, what the balance of different elements and ices is within the gas and dust, and how fast the disks dissipate.

Weinberger uses a variety of observational techniques and facilities, particularly ultra-high spatial-

Alan Boss is a theorist and an observational astronomer. His theoretical work focuses on the formation of binary and multiple stars, triggered collapse of the presolar cloud that eventually made  the Solar System, mixing and transport processes in protoplanetary disks, and the formation of gas giant and ice giant protoplanets. His observational works centers on the Carnegie Astrometric Planet Search project, which has been underway for the last decade at Carnegie's Las Campanas Observatory in Chile.

While fragmentation is universally recognized as the dominant formation mechanism for binary and multiple stars, there are still major questions. The most important of these

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