The entire universe—galaxies, stars, and planets—originally condensed from a vast network of tenuous, gaseous filaments, known as the intergalactic medium, or the gaseous cosmic web. Most of the matter in this giant reservoir has never been incorporated into galaxies; it keeps floating about in intergalactic space, largely in the form of ionized hydrogen gas.

 Michael Rauch is interested in all aspects of the intergalactic medium. He uses large telescopes, like the Magellans, to take spectra—light that reveals the chemical makeup of distant objects— of background quasars, which are highly energetic and extremely remote. He is looking for evidence of gas clouds located between the quasars and us. The hundreds of spectral absorption lines between us and each quasar—often referred to as the Lyman alpha forest—record changes in the cosmic web from the earliest galaxies to the present. Rauch and his collaborators have determined many of the basic properties of the intergalactic medium, including its matter density, temperature, chemistry, the small-scale density structure, and most recently, the turbulent motion in the gas.

 With his theorist colleagues, Rauch has also proposed and evaluated models for the interpretation of quasar spectra in the context of galaxy formation. He has participated in an observational survey of gravitationally lensed quasars and close pairs to study the large-scale motions in the gas. He wants to understand how the cosmic web follows the general expansion of the universe, how it stretches and contracts, and how it is funneled into future galaxies. Galaxies not only take in gas, they also return processed and chemically enriched matter back to the extragalactic realm. Rauch hopes to quantify the environmental impact of galaxies on the surrounding intergalactic medium.

Rauch also is performing ultra-deep experimental searches for faint radiation emitted by very distant, so-called high redshift galaxies and by the intergalactic medium itself. These observations may ultimately allow the construction of detailed images of the distribution of matter in the young universe.

Rauch received his undergraduate degree in physics from Gutenberg University in Germany, and a Ph. D. in astronomy from Cambridge University. From 1992 to 1995 he was a research associate at Carnegie then went to Caltech as a Hubble Fellow until 1998, when he became a staff astronomer at the European Southern Observatory before joining Carnegie as a staff astronomer. For more information see http://obs.carnegiescience.edu/users/mr

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September 1, 2021

Pasadena, CA—Astronomer Ana Bonaca, for whom the Milky Way galaxy is laboratory to explore the evolution of the universe, has joined the Carnegie Observatories as a Staff Scientist.

Bonaca arrived this month from Harvard University where she held a prestigious Institute for Theory and Computation Fellowship. Prior to that she completed her Ph.D. in astronomy from Yale University and a master’s degree in physics from the University of Zagreb.

Bonaca studies how the uneven pull of our galaxy’s gravity affects objects called globular clusters—spheres made up of a million stars bound together and orbiting a galactic core. The Milky Way is enveloped by a

June 29, 2021

Washington, DC—A team of Carnegie astronomers was awarded $1.4 million from the Heising-Simons Foundation to develop an ambitious and versatile infrared spectrograph for the Magellan telescopes at Carnegie’s Las Campanas Observatory in Chile that will enable breakthroughs in understanding cosmology, galaxy evolution, and exoplanet atmospheres.

Spearheaded by instrument lead Nicholas Konidaris and project scientists Andrew Newman and Gwen Rudie of the Carnegie Observatories, the project, called the Magellan Infrared Multiobject Spectrograph, or MIRMOS, will expand researchers’ view of the sky in the infrared wavelengths of the spectrum and significantly advance

NG4321 galaxy. Credit: ALMA (ESO/NAOJ/NRAO)/PHANGS, S. Dagnello (NRAO)
June 8, 2021

Pasadena, CA—A team of astronomers, including Carnegie’s Guillermo Blanc, used the  Atacama Large Millimeter/submillimeter Array (ALMA) to complete the first census of molecular clouds in the nearby universe, revealing that contrary to previous scientific opinion, these stellar nurseries do not all look and act the same. In fact, they’re as diverse as the people, homes, neighborhoods, and regions that make up our own world. 

Stars are formed out of clouds of dust and gas called molecular clouds, or stellar nurseries. Each stellar nursery in the universe can form thousands or even tens of thousands of new stars during its lifetime. Between 2013 and 2019

This artist's impression of the quasar P172+18. Credit: ESO/M. Kornmesser.
March 8, 2021

Pasadena, CA— The Magellan Baade telescope at Carnegie’s Las Campanas Observatory played an important role in the discovery of the most-distant known quasar with a bright radio emission, which was announced by a Max Planck Institute for Astronomy in Heidelberg and European Southern Observatory-led team and published in The Astrophysical Journal. One of the fastest-growing supermassive black holes ever observed, it is emitting about 580 times the energy as the entire Milky Way galaxy.

Quasars are incredibly luminous supermassive black holes accreting matter at the centers of massive galaxies. Their brightness allows astronomers to study them in detail even at great

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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/

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