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, and the first of two cameras for the Magellan Baade telescope. Magellan consortium astronomers use the Baade camera for various IR-imaging projects, while his group focuses on distant galaxies and supernovae.

Until recently, it was difficult to find large numbers of galaxies at near-IR wavelengths. But significant advances in the size of IR detector arrays have allowed the Persson group to survey one-square degree of sky. They find and measure thousands of these objects’ brightness, estimate their distances and intrinsic luminosities, and examine the way they cluster. The group is developing another camera with a focal plane IR detector array 25 times more powerful than that of the present camera to survey with unprecedented depth and area.

Serendipitously, Persson’s group (and others) found distant galaxies that emit virtually all of their energy in the infrared. These objects are so rare that enormous areas of sky must be studied to find them. Preliminary evidence suggests they are a varied population: most seem to be passively evolving objects in which star formation stopped several billion years ago, while some appear to have intense star formation within optically opaque dust clouds.

Persson and collaborators also study the distance-scale of the universe using newly found Type Ia supernovae—exploding stars that may provide the key to reconcile the timescale, geometry, and mass content of the universe within the framework of general relativity. These supernovae events appear to have a well-defined brightness and as they rise to maximum luminosity and decline, and equivalent luminosity at maximum, which can be used to determine relative distances.

To determine that local and distant supernovae are physically equivalent, the scientists are looking at their light variation over time at near-infrared wavelengths. This work is used to calibrate their distances and it is overcoming systematic effects that hamper optical observations.

Persson received his B.Sc. in physics from McGill University and his Ph.D. in astronomy from Caltech. Before joining Carnegie in 1975, he was a postdoctoral associate at Harvard College Observatory.

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May 13, 2022

Pasadena, CA— A team of astronomers led by University of Michigan’s Ian Roederer and including Carnegie’s Erika Holmbeck have identified the widest range of elements yet observed in a star beyond our own Sun. Their findings are published in The Astrophysical Journal Supplement Series.

The researchers identified 65 elements in the star, which is called HD 222925. Of these, 42 are from the bottom of the periodic table. Their identification will help astronomers understand one of the main methods by which the universe’s heavy elements were created—rapid neutron capture process.

"To the best of my knowledge, that's a record for any object

Alan Boss
January 14, 2022

Washington, DC— Carnegie’s Alan Boss was named one of 23 new Fellows of the American Astronomical Society. The honorees were chosen for their “extraordinary achievement and service” to the field.

Boss, whose contributions to the fields of astronomy and astrophysics are numerous, was specifically recognized for “innovative theoretical investigations of the formation of stars and exoplanets” as well as “tireless leadership within the exoplanet exploration community in ensuring that NASA executes a credible and successful exoplanet program.”

The AAS fellowship program began in 2020 and its members include professional astronomers

Mars mosaic courtesy of NASA.
January 13, 2022

Washington, DC—Organic molecules found in a meteorite that hurtled to Earth from Mars were synthesized during interactions between water and rocks that occurred on the Red Planet about 4 billion years ago, according to new analysis led by Carnegie’s Andrew Steele and published by Science.  

The meteorite, called Allan Hills (ALH) 84001, was discovered in the Antarctic in 1984 and is considered one of the oldest known projectiles to reach Earth from Mars.  

“Analyzing the origin of the meteorite’s minerals can serve as a window to reveal both the geochemical processes occurring early in Earth’s history and Mars’ potential for

The twin FPS units. Credit: The SDSS collaboration.
January 11, 2022

Pasadena, CA—After 21 years of observers loading heavy aluminum plates night after night, the Sloan Digital Sky Survey (SDSS) is now seeing the cosmos through robotic eyes. Following more than five years of design, development, and construction, survey members worked over the final months of 2021 to install the new robotic Focal Plane System (FPS) on the Sloan Foundation 2.5m Telescope at Apache Point Observatory (APO).

“We are thrilled to have reached this technological milestone despite being in the midst of a global pandemic and are excited to witness how this shift will enhance the work of the project,” said Juna Kollmeier. She is the Founding Director of

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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

Ana Bonaca is Staff Member at Carnegie Observatories. Her specialty is stellar dynamics and her research aims to uncover the structure and evolution of our galaxy, the Milky Way, especially the dark matter halo that surrounds it. In her research, she uses space- and ground-based telescopes to measure the motions of stars, and constructs numerical experiments to discover how dark matter affected them.

She arrived in September 2021 from Harvard University where she held a prestigious Institute for Theory and Computation Fellowship. 

Bonaca studies how the uneven pull of our galaxy’s gravity affects objects called globular clusters—spheres made up of a million

Peter Gao's research interests include planetary atmospheres; exoplanet characterization; planet formation and evolution; atmosphere-surface-interior interactions; astrobiology; habitability; biosignatures; numerical modeling.

His arrival in September 2021 continued Carnegie's longstanding tradition excellence in exoplanet discovery and research, which is crucial as the field prepares for an onslaught of new data about exoplanetary atmospheres when the next generation of telescopes come online.

Gao has been a part of several exploratory teams that investigated sulfuric acid clouds on Venus, methane on Mars, and the atmospheric hazes of Pluto. He also

Anne Pommier's research is dedicated to understanding how terrestrial planets work, especially the role of silicate and metallic melts in planetary interiors, from the scale of volcanic magma reservoirs to core-scale and planetary-scale processes.

She joined Carnegie in July 2021 from U.C. San Diego’s Scripps Institution of Oceanography, where she investigated the evolution and structure of planetary interiors, including our own Earth and its Moon, as well as Mars, Mercury, and the moon Ganymede.

Pommier’s experimental petrology and mineral physics work are an excellent addition to Carnegie’s longstanding leadership in lab-based mimicry of the

Johanna Teske became the first new staff member to join Carnegie’s newly named Earth and Planets Laboratory (EPL) in Washington, D.C., on September 1, 2020. She has been a NASA Hubble Fellow at the Carnegie Observatories in Pasadena, CA, since 2018. From 2014 to 2017 she was the Carnegie Origins Postdoctoral Fellow—a joint position between Carnegie’s Department of Terrestrial Magnetism (now part of EPL) and the Carnegie Observatories.

Teske is interested in the diversity in exoplanet compositions and the origins of that diversity. She uses observations to estimate exoplanet interior and atmospheric compositions, and the chemical environments of their formation