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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An artist’s conception of a type Ia supernova exploding, courtesy of ESO.
December 11, 2018

Pasadena, CA—New work from the Carnegie Supernova Project provides the best-yet calibrations for using type Ia supernovae to measure cosmic distances, which has implications for our understanding of how fast the universe is expanding and the role dark energy may play in driving this process. Led by Carnegie astronomer Chris Burns, the team’s findings are published in The Astrophysical Journal.  

Type Ia supernovae are fantastically bright stellar phenomena. They are violent explosions of a white dwarf—the crystalline remnant of a star that has exhausted its nuclear fuel—which is part of a binary system with another star.

In addition to being

Pan-STARRS image showing the host galaxy of the newly discovered supernova ASASSN-18bt
November 29, 2018

Pasadena, CA—A supernova discovered by an international group of astronomers including Carnegie’s Tom Holoien and Maria Drout, and led by University of Hawaii’s Ben Shappee, provides an unprecedented look at the first moments of a violent stellar explosion. The light from the explosion's first hours showed an unexpected pattern, which Carnegie's Anthony Piro analyzed to reveal that the genesis of these phenomena is even more mysterious than previously thought.

Their findings are published in a trio of papers in The Astrophysical Journal and The Astrophysical Journal Letters. (You can read them here, here, and here.)

Type Ia supernovae are

SDSS/Caltech/Keck
October 11, 2018

Pasadena, CA—Carnegie’s Anthony Piro was part of a Caltech-led team of astronomers who observed the peculiar death of a massive star that exploded in a surprisingly faint and rapidly fading supernova, possibly creating a compact neutron star binary system. Piro’s theoretical work provided crucial context for the discovery. Their findings are published by Science.

Observations made by the Caltech team—including lead author Kishalay De and project principal investigator Mansi Kasliwal (herself a former-Carnegie postdoc)—suggest that the dying star had an unseen companion, which gravitationally siphoned away most of the star's mass before it exploded

John Graham
September 24, 2018

Washington, DC—Carnegie astronomer John Graham—who also served during different periods as both Vice President and Secretary of the American Astronomical Society—died at home in Washington, D.C., September 13 after a battle with brain cancer. He was 79.

Graham, who specialized in the observation of young stars and the star formation process in the Milky Way and neighboring galaxies, joined Carnegie’s Department of Terrestrial Magnetism from the Cerro Tololo Inter-American Observatory in 1985. George Preston, who was Director of the Carnegie Observatories at the time Graham came to DTM, also offered Graham a simultaneous five-year adjunct appointment at the

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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/

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

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

Leopoldo Infante became the director of the Las Campanas Observatory on July 31, 2017.

Since 2009, Infante has been the founder and director of the Centre for Astro-Engineering at the Chilean university. He joined PUC as an assistant professor in 1990 and has been a full professor since 2006. He was one of the creators of PUC’s Department of Astronomy and Astrophysics, and served as its director from 2000 to 2006. He also established the Chilean Astronomical Society (SOCHIAS) and served as its president from 2009 to 2010.

Infante received his B.Sc. in physics at PUC. He then acquired a MSc. and Ph.D. in physics and astronomy from the University of Victoria in