John Mulchaey, director of the Observatories, serves as co-interim president of Carnegie as of January 1, 2018. He investigates groups and clusters of galaxies, elliptical galaxies, dark matter—the invisible material that makes up most of the universe—active galaxies and black holes. He is also a scientific editor for The Astrophysical Journal and is actively involved in public outreach and education.

Most galaxies including our own Milky Way, exist in collections known as groups, which are the most common galaxy systems and are important laboratories for studying galaxy formation and evolution. Mulchaey studies galaxy groups to understand the processes that affect most galaxies during their lifetimes.

As a graduate student, Mulchaey led the team that discovered that some groups are bright X-ray sources. The extent of the emission suggests that the X-rays originated in a very hot, low-density gas called the intragroup medium. X-ray observations of the medium have shown that the temperature is a scorching 10 million degrees. Temperatures this high should quickly disperse; but the intragroup medium does not. Astronomers believe that gravity is binding it. However, the mass required to confine the gas is much higher than the visible group mass. This suggests that galaxy groups are dominated by that elusive material called dark matter, which does not emit light but has a strong gravitational pull.

Although Mulchaey works extensively with space-based, X-ray telescopes, the optical telescopes at Carnegie’s Las Campanas Observatory play a central role in his research. X-ray images alone are not sufficient to uncover the nature of galaxy groups. Follow-up observations with large-aperture optical telescopes, such as Magellan, are necessary to determine galaxy type and distance.

The large Magellan telescopes have allowed Mulchaey to study distant galaxy groups for the first time. He is directly tracing how the group environment affects properties of individual galaxies. These observations suggest that galaxy-galaxy merging is very common in groups. For some groups, the galaxies may continue merging until they form a single massive galaxy. In the last few years, Mulchaey has uncovered several of these “fossil group” systems. Studies of them are proving to have important clues into the likely end state of most groups, including the Local Group, where our Milky Way resides.

Mulchaey received his B.S. in astrophysics from UC-Berkeley and his Ph. D. from the University of Maryland. He was a fellow at the Space Telescope Science Institute and at Carnegie before joining the  Carnegie staff. For more information see http://obs.carnegiescience.edu/users/mulchaey

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August 9, 2018

Washington, D.C.—Observatories NASA Hubble Postdoctoral Fellow Maria Drout will receive the tenth Postdoctoral Innovation and Excellence Award (PIE). These awards are made through nominations from the departments and are chosen by the Office of the President. The recipients are awarded a cash prize for their exceptionally creative approaches to science, strong mentoring, and contributing to the sense of campus community.

Maria Drout was one of four Carnegie astronomers who, along with colleagues from UC Santa Cruz, provided the first-ever glimpse of two neutron stars colliding last August. She was first author on a Science paper, which measured the changing light from that merger

August 2, 2018

Pasadena, CA—What happens when a star behaves like it exploded, but it’s still there?

About 170 years ago, astronomers witnessed a major outburst by Eta Carinae, the brightest known star in our Milky Way galaxy. The blast unleashed almost as much energy as a standard supernova explosion.

Yet, Eta Carinae survived.

An explanation for the eruption has eluded astrophysicists, but Carnegie telescopes played an important role in solving the mystery.

Researchers can’t t a time machine back to the mid-1800s to observe the outburst with modern technology. However, astronomers can use nature’s own “time machine,” courtesy of the fact that light travels at a finite

This artist’s impression shows the temperate planet Ross 128 b, with its red dwarf parent star in the background. It is provided courtesy of ESO/M. Kornmesser.
July 10, 2018

Pasadena, CA—Last autumn, the world was excited by the discovery of an exoplanet called Ross 128 b, which is just 11 light years away from Earth. New work from a team led by Diogo Souto of Brazil’s Observatório Nacional and including Carnegie’s Johanna Teske has for the first time determined detailed chemical abundances of the planet’s host star, Ross 128.

Understanding which elements are present in a star in what abundances can help researchers estimate the makeup of the exoplanets that orbit them, which can help predict how similar the planets are to the Earth.

“Until recently, it was difficult to obtain detailed chemical abundances for this kind of star,” said lead

An artist’s conception of a radio jet spewing out fast-moving material from the newly discovered quasar. Artwork by Robin Dienel, courtesy of Carnegie Institution for Science.
July 9, 2018

Pasadena, CA—Carnegie’s Eduardo Bañados led a team that found a quasar with the brightest radio emission ever observed in the early universe, due to it spewing out a jet of extremely fast-moving material.

Bañados’ discovery was followed up by Emmanuel Momjian of the National Radio Astronomy Observatory, which allowed the team to see with unprecedented detail the jet shooting out of a quasar that formed within the universe’s first billion years of existence. 

The findings, published in two papers in The Astrophysical Journal, will allow astronomers to better probe the universe’s youth during an important period of transition to its current state.

Quasars are comprised

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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 improved the

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 will

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/ccd/caps.

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. 

Nick Konidaris is a staff scientist at the Carnegie Observatories and Instrument Lead for the SDSS-V Local Volume Mapper (LVM). He works on a broad range of new optical instrumentation projects in astronomy and remote sensing. Nick's projects range from experimental to large workhorse facilities. On the experimental side, he recently began working on a new development platform for the 40-inch Swope telescope at Carnegie's Las Campanas Observatory that will be used to explore and understand the explosive universe.

 Nick and his colleagues at the Department of Global Ecology are leveraging the work on Swope to develop a new airborne spectrograph that will be used to provide a direct

Experimental petrologist Michael Walter became director of the Geophysical Laboratory beginning April 1, 2018. His recent research has focused on the period early in Earth’s history, shortly after the planet accreted from the cloud of gas and dust surrounding our young Sun, when the mantle and the core first separated into distinct layers. Current topics of investigation also include the structure and properties of various compounds under the extreme pressures and temperatures found deep inside the planet, and information about the pressure, temperature, and chemical conditions of the mantle that can be gleaned from mineral impurities preserved inside diamonds.

Walter had been at

Guoyin Shen's research interests lie in the quest to establish and to examine models for explaining and controlling the behavior of materials under extreme conditions. His research activities include investigation of phase transformations and melting lines in molecular solids, oxides and metals; polyamorphism in liquids and amorphous materials; new states of matter and their emergent properties under extreme conditions; and the development of enabling high-pressure synchrotron techniques for advancing compression science. 

He obtained a Ph.D. in mineral physics from Uppsala University, Sweden in 1994 and a B.S. in geochemistry from Zhejiang University, China in 1982. For more