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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The Magellan Telescopes at Carnegie's Las Campanas Observatory in Chile
September 6, 2022

Washington, DC— An anonymous bequest of $34.8 million will enable Carnegie to continue to play a leading role advancing the frontiers of astronomy and astrophysics. The largest gift to the Institution since it was founded by Andrew Carnegie, this new fund will support staff and instrumentation at the Carnegie Observatories.

“Since George Ellery Hale built the first telescope on Mount Wilson, Carnegie has played a forefront role in some of the most important astronomical discoveries of the modern era,” said Carnegie President Eric D. Isaacs. “This transformative gift will empower new generations of Carnegie astronomers to reveal the physics that underpins

Artist's concept of the Giant Magellan Telescope courtesy of GMTO
August 2, 2022
Washington, DC—A Carnegie-led effort secured $205 million toward the completion of the next-generation Giant Magellan Telescope, which is currently being built at our Las Campanas Observatory in Chile. When completed, the GMT will enable breakthrough astronomy—from revealing the fundamental physics underpinning the cosmos to advancing our ability to search for life on distant worlds.

Last November, the National Academies of Science, Engineering, and Medicine ranked the GMT as a top strategic priority, recommending an injection of federal support to complete its construction and bring about a new era in astronomy. The endorsement was part of the academies’ review of the

Artist's conception of JWST. Credit: NASA GSFC/CIL/Adriana Manrique Gutierrez
July 24, 2022

Pasadena, CA— The first of six projects led by Carnegie-affiliated astronomers will, for the next three days, use the James Webb Space Telescope to make some of the most-accurate measurements ever taken of the chemistry of very early galaxies—studying light that traveled 10 billion years to reach us.

Carnegie’s Gwen Rudie and Allison Strom, formerly a Carnegie-Princeton Postdoctoral Fellow, now a Northwestern professor, are heading up the CECILIA project, which will take extremely accurate measurements from a carefully selected set of ancient galaxies in order to understand their compositions and chart the remarkable growth that they experienced in the universe

June 28, 2022

Washington, DC—The violent event that likely preceded our Solar System’s formation holds the solution to a longstanding meteorite mystery, says new work from Carnegie’s Alan Boss published in The Astrophysical Journal.

The raw material from which our Solar System was constructed was dispersed when the shock wave from an exploding supernova injected material into a cloud of dust and gas, causing it to collapse in on itself. In the aftermath of this event, most of the injected matter was gravitationally drawn into the center of the whirlwind, where the intense buildup of pressure enabled nuclear fusion to commence, and the Sun was born. The young star was

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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