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 their stellar and gaseous contents.

When nearby galaxies collide and merge they yield valuable clues about processes that occurred much more frequently in the younger, distant universe. When two gas-rich galaxies collide, their pervasive interstellar gas gets compressed, clumps into dense clouds, and fuels the sudden birth of billions of new stars and thousands of star clusters.

Some of the newborn clusters are so dense that they survive a merger intact and orbit in the remnant galaxy for billions of years as "globular clusters." Schweizer and collaborators use the Hubble Space Telescope to search for young globulars and study their formation and evolution. Follow-up analysis with Magellan and other ground-based telescopes then yields the clusters' velocities, chemical compositions, and ages.

 Schweizer is also collaborating with astronomers using NASA's Chandra X-ray Observatory to study point sources and the hot interstellar gas in merger galaxies. The team’s observations seem to connect the X-ray point sources to black holes being dynamically ejected from the newborn star clusters. The data yield direct measurements of the chemical enrichment of the gas by exploding stars called supernovae.

Schweizer received his undergraduate degree in astronomy from the University of Bern. He received both his M.A. and Ph. D. from UC-Berkeley in astronomy. Before joining Carnegie as a staff astronomer in 1981 he was an associate and then assistant astronomer at Cerro Tololo Inter-American Observatory in Chile. Before that he served as a postdoctoral fellow at Carnegie.  For more  information see http://obs.carnegiescience.edu/users/schweize

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Widmanstatten pattern characteristic of iron meteorites, courtesy of Peng Ni.
August 3, 2020

Washington, DC— Work led by Carnegie’s Peng Ni and Anat Shahar uncovers new details about our Solar System’s oldest planetary objects, which broke apart in long-ago collisions to form iron-rich meteorites.  Their findings reveal that the distinct chemical signatures of these meteorites can be explained by the process of core crystallization in their parent bodies, deepening our understanding of the geochemistry occurring in the Solar System’s youth. They are published by Nature Geoscience.

Many of the meteorites that shot through our planet’s atmosphere and crashed on its surface were once part of larger objects that broke up at some point in our

Phoenix Stellar Stream illustration courtesy of Geraint F. Lewis.
July 29, 2020

Pasadena, CA—A team of astronomers including Carnegie’s Ting Li and Alexander Ji discovered a stellar stream composed of the remnants of an ancient globular cluster that was torn apart by the Milky Way’s gravity 2 billion years ago, when Earth’s most-complex lifeforms were single-celled organisms. This surprising finding, published in Nature, upends conventional wisdom about how these celestial objects form.

Imagine a sphere made up of a million stars bound by gravity and orbiting a galactic core. That’s a globular cluster. The Milky Way is home to about 150 of them, which form a tenuous halo that envelops our galaxy.

But the globular cluster

The du Pont telescope, courtesy Matias del Campo
July 20, 2020

Pasadena, CA— Filling in the most-significant gaps in our understanding of the universe’s history, the Sloan Digital Sky Survey (SDSS) released Sunday a comprehensive analysis of the largest three-dimensional map of the cosmos ever created.

The survey, of which Carnegie is an integral member, has been one of the most successful and influential in the history of astronomy. It operates out of both Apache Point Observatory in New Mexico, home of the survey’s original 2.5-meter telescope, and Carnegie’s Las Campanas Observatory in Chile, where it uses Carnegie’s du Pont telescope.

The new results come from the extended Baryon Oscillation

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.

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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. 

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 collecting data for 30 years, using the Precision Doppler technique.  Highlights of this program include the detection of five of the first six exoplanets, the first eccentric planet, the first multiple planet system, the first sub-Saturn mass planet, the first sub-Neptune mass planet, the first terrestrial mass planet, and the first transit planet.Over the course of 30 years we have

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  http://instrumentation.obs.carnegiescience.edu/

Brittany Belin joined the Department of Embryology staff in August 2020. Her Ph.D. research involved developing new tools for in vivo imaging of actin in cell nuclei. Actin is a major structural element in eukaryotic cells—cells with a nucleus and organelles —forming contractile polymers that drive muscle contraction, the migration of immune cells to  infection sites, and the movement of signals from one part of a cell to another. Using the tools developed in her Ph.D., Belin discovered a new role for actin in aiding the repair of DNA breaks in human cells caused by carcinogens, UV light, and other mutagens.

Belin changed course for her postdoctoral work, in

Evolutionary geneticist Moises Exposito-Alonso joined the Department of Plant Biology as a staff associate in September 2019. He investigates whether and how plants will evolve to keep pace with climate change by conducting large-scale ecological and genome sequencing experiments. He also develops computational methods to derive fundamental principles of evolution, such as how fast natural populations acquire new mutations and how past climates shaped continental-scale biodiversity patterns. His goal is to use these first principles and computational approaches to forecast evolutionary outcomes of populations under climate change to anticipate potential future

Staff Associate Kamena Kostova joined the Department of Embryology in November 2018. She studies ribosomes, the factory-like structures inside cells that produce proteins. Scientists have known about ribosome structure, function, and biogenesis for some time. But, a major unanswered question is how cells monitor the integrity of the ribosome itself. Problems with ribosomes have been associated with diseases including neurodegeneration and cancer. The Kostova lab investigates the fundamental question of how cells respond when their ribosomes break down using mass spectrometry, functional genomics methods, and CRISPR genome editing.

Kostova received a B.S. in Biology from the

Sally June Tracy applies cutting-edge experimental and analytical techniques to understand the fundamental physical behavior of materials at extreme conditions. She uses dynamic compression techniques with high-flux X-ray sources to probe the structural changes and phase transitions in materials at conditions that mimic impacts and the interiors of terrestrial and exoplanets. She is also an expert in nuclear resonant scattering and synchrotron X-ray diffraction. She uses these techniques to understand novel behavior at the electronic level.  Tracy received her Ph.D. from the California Institute of