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. Shectman was the former project scientist for Magellan and is largely responsible for the superb quality of 6.5-meter telescopes. He is now a member of the Giant Magellan Telescope Project Scientists’ Working Group.

 To understand large-scale structure, Shectman has participated in several galaxy surveys. He and collaborators discovered a particularly large void in the galaxy distribution in the early 1980s and subsequently conducted the Las Campanas Redshift Survey (LCRS) using the C100 fiber spectrograph—a device that collects light, disperses it into spectra to reveal the chemistry and other features. The LCRS was the definitive distance survey of the time and showed that the galaxy distribution becomes homogeneous at large scales compared with the strong fluctuations characteristic of the small-scale distribution.

Hydrogen and helium were produced in the Big Bang, but heavier elements came from nucleosynthesis in successive stellar generations. The oldest stars are deficient in heavy elements, what astronomers call metal-poor. In the 1980s, Shectman and George Preston conducted a survey for these objects. Using novel techniques they discovered the majority of known stars with heavy-element abundances less than about 1% of the Sun’s. Shectman has also worked on metal-poor stars in the Hamburg-ESO survey, using Magellan spectrographs to identify and study the best ones in detail.

 Shectman developed a series of photon-counting detectors for faint-object spectroscopy. They were used at Las Campanas and copied by other observatories. He also built the high-resolution echelle spectrograph and the multiobject fiber spectrograph for the 100-inch du Pont telescope. With Rebecca Bernstein, he built the high-resolution echelle spectrograph for Magellan, which has been in service for several years. He is currently working on the Magellan echellette spectrograph, a joint MIT-Carnegie project with Scott Burles (MIT) and Carnegie’s Ian Thompson, and the Magellan Planet Finder, a collaboration with Carnegie’s Paul Butler and Jeff Crane.

Shectman received his B.S. in physics from Yale Univesity and a Ph. D. in astronomy from Caltech where he was also a National Science Foundation fellow. Before joining the Carnegie staff in 1975, he was a postdoctoral fellow at the University of Michigan. For more information see http://obs.carnegiescience.edu/users/shec

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Explore Carnegie Science

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.

The Magellan telescopes at LCO by Yuri Beletsky.
April 27, 2020

Pasadena, CA— The universe is full of billions of galaxies—but their distribution across space is far from uniform. Why do we see so much structure in the universe today and how did it all form and grow? 

A 10-year survey of tens of thousands of galaxies made using the Magellan Baade Telescope at Carnegie’s Las Campanas Observatory in Chile provided a new approach to answering this fundamental mystery. The results, led by Carnegie’s Daniel Kelson, are published in Monthly Notices of the Royal Astronomical Society. 

“How do you describe the indescribable?” asks Kelson. “By taking an entirely new approach to the problem.

Caltech logo
March 17, 2020

The Carnegie Institution for Science is consolidating our California research departments into an expanded presence in Pasadena. With this move, we are building on our existing relationship with Caltech, with a goal of broadening our historic collaborations in astronomy and astrophysics and pursuing new opportunities in ecology and plant biology that will support the global fight against climate change.

This plan, which affects our research operations in Pasadena and Palo Alto, reflects Carnegie’s ongoing efforts to extend our leadership in space, Earth, and life sciences and to enhance our ability to explore new frontiers.

In selecting our Pasadena location, we

 Illustration of DS Tuc AB by M. Weiss, CfA.
March 9, 2020

Pasadena, CA— A new kind of astronomical observation helped reveal the possible evolutionary history of a baby Neptune-like exoplanet.

To study a very young planet called DS Tuc Ab, a Harvard & Smithsonian Center for Astrophysics-led team that included six Carnegie astronomers—Johanna Teske, Sharon Wang, Stephen Shectman, Paul Butler, Jeff Crane, and Ian Thompson—developed a new observational modeling tool. Their work will be published in The Astrophysical Journal Letters and represents the first time the orbital tilt of a planet younger than 45 million years—or about 1/100th the age of the Solar System—has been measured.

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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/

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

The Ludington lab investigates complex ecological dynamics from microbial community interactions using the fruit fly  Drosophila melanogaster. The fruit fly gut carries numerous microbial species, which can be cultured in the lab. The goal is to understand the gut ecology and how it relates to host health, among other questions, by taking advantage of the fast time-scale and ease of studying the fruit fly in controlled experiments.