JPL News: NuSTAR Finds Cosmic Clumpy Doughnut Around Black Hole

The most massive black holes in the universe are often encircled by thick, doughnut-shaped disks of gas and dust. This deep-space doughnut material ultimately feeds and nourishes the growing black holes tucked inside.

Until recently, telescopes weren't able to penetrate some of these doughnuts, also known as tori.

"Originally, we thought that some black holes were hidden behind walls or screens of material that could not be seen through," said Andrea Marinucci of the Roma Tre University in Italy, lead author of a new Monthly Notices of the Royal Astronomical Society study describing results from NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, and the European Space Agency's XMM-Newton space observatory.

"NuSTAR was built to peer deep into the hearts of dust-enshrouded galaxies. By extending its reach to high energy X-rays, which are inherently penetrating, NuSTAR can study objects like this which would otherwise be invisible to low energy X-ray telescopes," says Fiona Harrison, NuSTAR's principal investigator, as well as Caltech's Benjamin M. Rosen Professor of Physics and Astronomy and the Kent and Joyce Kresa Leadership Chair of the Division of Physics, Mathematics and Astronomy.

With its X-ray vision, NuSTAR recently peered inside one of the densest of these doughnuts known to surround a supermassive black hole. This black hole lies at the center of a well-studied spiral galaxy called NGC 1068, located 47 million light-years away in the Cetus constellation.

The observations revealed a clumpy, cosmic doughnut.

"The rotating material is not a simple, rounded doughnut as originally thought, but clumpy," said Marinucci.

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15 for 2015: The Year in Research News at Caltech

The year 2015 proved to be another groundbreaking year for research at Caltech. From seeing quantum motion, to reconfiguring jellyfish limbs, to measuring stellar magnetic fields, researchers continued to ask and answer the deepest scientific questions.

In case you missed any of them, here are 15 stories highlighting a few of the discoveries, methods, and technologies that came to life at Caltech in 2015.

 

 

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Here are 15 stories highlighting a few of the discoveries, methods, and technologies that came to life at Caltech in 2015.

15 for 2015: The Year in Research News at Caltech

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Credit: K.Batygin/Caltech

New Research Suggests Solar System May Have Once Harbored Super-Earths

Thanks to recent surveys of exoplanets—planets in solar systems other than our own—we know that most planetary systems typically have one or more super-Earths (planets that are substantially more massive than Earth but less massive than Neptune) orbiting closer to their suns than Mercury does. In March, researchers showed that our own solar system may have once had these super-Earths, but they were destroyed by Jupiter's inward and outward migration through the solar system. This migration would have gravitationally flung small planetesimals through the solar system, setting off chains of collisions that would push any interior planets into the sun.
Credit: Lance Hayashida/Caltech and the Hoelz Laboratory/Caltech

Caltech Biochemists Shed Light on Cellular Mystery

The nuclear pore complex (NPC) is an intricate portal linking the cytoplasm of a cell to its nucleus. It is made up of many copies of about 34 different proteins. Around 2,000 NPCs are embedded in the nuclear envelope of a single human cell and each NPC shuttles hundreds of macromolecules of different shapes and sizes between the cytoplasm and nucleus. In February, Caltech biochemists determined the structure of a significant portion of the NPC called the outer rings; in August, the same group solved the structure of the pore's inner ring. Understanding the structure of the NPC could lead to new classes of cancer drugs as well as antiviral medicines.
Credit: iStockphoto

Research Suggests Brain's Melatonin May Trigger Sleep

For decades, supplemental melatonin has been sold over the counter as a sleep aid despite the absence of scientific evidence proving its effectiveness. Few studies have investigated melatonin produced naturally in the human body. This March, Caltech researchers studying zebrafish—animals that, like humans, are awake during the day and asleep at night—determined that the melatonin hormone does help the body fall asleep and stay asleep. Specifically, they found that zebrafish larvae that could not produce melatonin slept for only half as long as normal larvae.
Credit: Gregg Hallinan/Caltech

Advances in Radio Astronomy

In May, a new radio telescope array called the Owens Valley Long Wavelength Array (OV-LWA) saw its first light. Developed by a consortium led by Caltech, the OV-LWA has the ability to image simultaneously the entire sky at radio wavelengths with unmatched speed, helping astronomers to search for objects and phenomena that pulse, flicker, flare, or explode.

In July, Caltech researchers used both radio and optical telescopes to observe a brown dwarf located 20 light-years away and found that these so-called failed stars host powerful auroras near their magnetic poles.
Credit: Michael Abrams and Ty Basinger

Injured Jellyfish Seek to Regain Symmetry

Some kinds of animals can regrow lost limbs and body parts, but moon jellyfish have a different strategy. In June, Caltech researchers reported that the star-shaped eight-armed moon jellyfish rearranges itself when injured to maintain symmetry. It is hypothesized that the rearrangement helps to preserve the jellyfish's propulsion mechanism.
Credit: NASA/JPL-Caltech

Geologists Characterize Nepal Earthquake

In April, a magnitude 7.8 earthquake rocked Nepal. While the damage was extensive, it was not as severe as many geologists predicted. This year, a Caltech team of geologists used satellite radar imaging data and measurements from seismic instruments in Nepal to create models of fault rupture and ground movement. They found that the quake ruptured only a small fraction of the "locked" tectonic plate and that there is still the potential for the locked portion to produce a large earthquake.
Credit: Caltech/JPL

New Polymer Creates Safer Fuels

Plane crashes cause devastating damage, but this damage is often exacerbated by the highly explosive nature of jet fuel. This October, researchers at Caltech and JPL discovered a polymeric fuel additive that can reduce the intensity of postimpact explosions that occur during accidents and crashes. Preliminary results show that the additive can provide this benefit without adversely affecting fuel performance. The polymer works by inhibiting "misting"—the process that causes fuel to rapidly disperse and easily catch fire—under crash conditions.
Credit: Spencer Kellis/Caltech

Controlling a Robotic Arm with a Patient's Intentions

When you reach for a glass of water, you do not consciously think about moving your arm muscles or grasping with your fingers—you think about the goal of the movement. This May, by implanting neural prosthetic devices into the posterior parietal cortex (PCC)—the region of the brain that governs intentions for movement—rather than the motor cortex, which controls movement, Caltech researchers enabled a paralyzed patient to more smoothly and naturally control a prosthetic limb. In November, the researchers showed that there are individual neurons in the PPC that encode for entire hand shapes, such as those used for grasping or gesturing.

 

Caltech Scientists Develop Cool Process to Make Better Graphene

Graphene is an ultrastrong and conductive material made of a single layer of carbon atoms. While it is a promising material for scientific and engineering advances, manufacturing it on an industrially relevant scale has proven to be impractical, requiring temperatures of around 1,800 degrees Fahrenheit and long periods of time. A new technique invented at Caltech allows the speedy production of graphene—in just a few minutes—at room temperatures. The technique also produces graphene that is stronger, smoother, and more electrically conductive than normally produced synthetic graphene.
Credit: Rafael A. García (SAp CEA), Kyle Augustson (HAO), Jim Fuller (Caltech) & Gabriel Pérez (SMM, IAC), Photograph from AIA/SDO

Astronomers Peer Inside Stars, Finding Giant Magnets

Before this October, astronomers have only been able to study the magnetic fields of stars on the stellar surfaces. Now, using a technique called asteroseismology, scientists were able to probe the fusion-powered hearts of dozens of red giants (stars that are evolved versions of our sun) to calculate the magnetic field strengths inside those stars. They found that the internal magnetic fields of the red giants were as much as 10 million times stronger than Earth's magnetic field. Magnetic fields play a key role in the interior rotation rate of stars, which has a dramatic effect on how the stars evolve.
Credit: Chan Lei and Keith Schwab/Caltech

Seeing Quantum Motion

To the casual observer, an object at rest is just that—at rest, motionless. But on the subatomic scale, the object is most certainly in motion—quantum mechanical motion. Quantum motion, or noise, is ever-present in nature, and in August, Caltech researchers discovered how to observe and manipulate that motion in a small device. By creating what they called a "quantum squeezed state," they were able to periodically reduce the quantum fluctuations of the device. The ability to control quantum noise could one day be used to improve the precision of very sensitive measurements.
Credit: Ali Hajimiri/Caltech

New Camera Chip Provides Superfine 3-D Resolution

3-D printing can produce a wide array of objects in relatively little time, but first the printer needs to have a blueprint of what to print. The blueprints are provided by 3-D cameras, which scan objects and create models for the printer. Caltech researchers have now developed a 3-D camera that produces the highest depth-measurement accuracy of any similar device, allowing it to deliver replicas of an object to be 3-D printed within microns of similarity to the original object. In addition, the camera, known as a nanophotonic coherent imager, is inexpensive and small.
Credit: Image provided courtesy of Joint Center for Artificial Photosynthesis; artwork by Darius Siwek.

One Step Closer to Artificial Photosynthesis and 'Solar Fuels'

Plants are masters of photosynthesis—the process of turning carbon dioxide, sunlight, and water into oxygen and sugar. Inspired by this natural and energy-efficient process, Caltech researchers have created an "artificial leaf" that takes in CO2, sunlight, and water to produce hydrogen fuels. This solar-powered system, one researcher says, shatters all of the combined safety, performance, and stability records for artificial leaf technology by factors of 5 to 10 or more.
Credit: Santiago Lombeyda and Robin Betz

Potassium Salt Outperforms Precious Metals As a Catalyst

Rare precious metals have been the standard catalyst for the formation of carbon-silicon bonds, a process crucial to the synthesis of a host of products from new medicines to advanced materials. However, they are expensive, inefficient, and produce toxic waste byproducts. This February, Caltech researchers discovered a much more sustainable catalyst in the form of a simple potassium salt that is one of the most abundant metals on Earth and thousands of times less expensive than other commonly used catalysts. In addition, the potassium salt is much more effective at running challenging chemical reactions than state-of-the-art precious metal complexes.
Credit: Qi Zhao/National University of Singapore

Probing the Mysterious Perceptual World of Autism

The way in which people with autism spectrum disorder (ASD) perceive the world is unique. It has been a long-standing belief that people with ASD often miss facial cues, contributing to impaired social interaction. In a study published in October, Caltech researchers showed 700 images to 39 subjects and found that people with ASD pay closer attention to simple edges and patterns in images than to the faces of people. The study also found that subjects were strongly attracted to the center of images—regardless of what was placed there—and to differences in color and contrast rather than facial features. These findings may help doctors diagnose and more effectively treat the different forms of autism.
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The year 2015 proved to be another groundbreaking year for research at Caltech. From seeing quantum motion, to reconfiguring jellyfish limbs, to measuring stellar magnetic fields, researchers continued to ask and answer the deepest scientific questions.

In case you missed any of them, here are 15 stories highlighting a few of the discoveries, methods, and technologies that came to life at Caltech in 2015.

Written by Lori Dajose

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Simulation Shows Key to Building Powerful Magnetic Fields

When certain massive stars use up all of their fuel and collapse onto their cores, explosions 10 to 100 times brighter than the average supernova occur. Exactly how this happens is not well understood. Astrophysicists from Caltech, UC Berkeley, the Albert Einstein Institute, and the Perimeter Institute for Theoretical Physics have used the National Science Foundation's Blue Waters supercomputer to perform three-dimensional computer simulations to fill in an important missing piece of our understanding of what drives these blasts.  

The researchers report their findings online on November 30 in advance of publication in the journal Nature. The lead author on the paper is Philipp Mösta, who started the work while a postdoctoral scholar at Caltech and is now a NASA Einstein Fellow at UC Berkeley.

The extremely bright explosions come in two varieties—some are a type of energetic supernovae called hypernovae, while others are gamma-ray bursts (GRBs). Both are driven by focused jets formed in some collapsed stellar cores. In the case of GRBs, the jets themselves escape the star at close to the speed of light and emit strong beams of extremely energetic light called gamma rays. The necessary ingredients to create such jets are rapid rotation and a magnetic field that is a million billion times stronger than Earth's own magnetic field.

In the past, scientists have simulated the evolution of massive stars from their collapse to the production of these jet-driven explosions by factoring unrealistically large magnetic fields into their models—without explaining how they could be generated in the first place. But how could magnetic fields strong enough to power the explosions exist in nature?

"That's what we were trying to understand with this study," says Luke Roberts, a NASA Einstein Fellow at Caltech and a coauthor on the paper. "How can you start with the magnetic field you might expect in a massive star that is about to collapse—or at least an initial magnetic field that is much weaker than the field required to power these explosions—and build it up to the strength that you need to collimate a jet and drive a jet-driven supernova?"

For more than 20 years, theory has suggested that the magnetic field of the inner- most regions of a massive star that has collapsed, also known as a proto-neutron star, could be amplified by an instability in the flow of its plasma if the core is rapidly rotating, causing its outer edge to rotate faster than its center. However, no previous models could prove this process could strengthen a magnetic field to the extent needed to collimate a jet, largely because these simulations lacked the resolution to resolve where the flow becomes unstable.


Magnetic field amplification in hypernovae
Supercomputer visualization of the toroidal magnetic field in a collapsed, massive star, showing how in a span of 10 milliseconds the rapid differential rotation revs up the stars magnetic field to a million billion times that of our sun (yellow is positive, light blue is negative). Red and blue represent weaker positive and negative magnetic fields, respectively. Credit: Philipp Mösta

Mösta and his colleagues developed a simulation of a rapidly rotating collapsed stellar core and scaled it so that it could run on the Blue Waters supercomputer, a powerful supercomputer funded by the NSF located at the National Center for Supercomputing Applications at the University of Illinois. Blue Waters is known for its ability to provide sustained high-performance computing for problems that produce large amounts of information. The team's highest-resolution simulation took 18 days of around-the-clock computing by about 130,000 computer processors to simulate just 10 milliseconds of the core's evolution.

In the end, the researchers were able to simulate the so-called magnetorotational instability responsible for the amplification of the magnetic field. They saw—as theory predicted—that the instability creates small patches of an intense magnetic field distributed in a chaotic way throughout the core of the collapsed star.

"Surprisingly, we found that a dynamo process connects these patches to create a larger, ordered structure," explains David Radice, a Walter Burke Fellow at Caltech and a coauthor on the paper. An early type of electrical generator known as a dynamo produced a current by rotating electromagnetic coils within a magnetic field. Similarly, astrophysical dynamos generate currents when hydromagnetic fluids in stellar cores rotate under the influence of their magnetic fields. Those currents can then amplify the magnetic fields.

"We find that this process is able to create large-scale fields—the kind you would need to power jets," says Radice.

The researchers also note that the magnetic fields they created in their simulations are similar in strength to those seen in magnetars—neutron stars (a type of stellar remnant) with extremely strong magnetic fields. "It takes thousands or millions of years for a proto-neutron star to become a neutron star, and we have not yet simulated that. But if you could transport this thing thousands or millions of years forward in time, you would have a strong enough magnetic field to explain magnetar field strengths," says Roberts. "This might explain some fraction of magnetars or a particular class of very bright supernovae that are thought to be powered by a spinning magnetar at their center."

Additional authors on the paper, "A large-scale dynamo and magnetoturbulence in rapidly rotating core-collapse supernovae," are Christian Ott, professor of theoretical astrophysics; Erik Schnetter of the Perimeter Institute for Theoretical Physics, the University of Guelph, and Louisiana State University; and Roland Haas of the Max Planck Institute for Gravitational Physics in Potsdam-Golm, Germany. The work was partially supported by the Sherman Fairchild Foundation, by grants from the NSF, by NASA Einstein Fellowships, and by an award from the Natural Sciences and Engineering Research Council of Canada.

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How to Power Jet-Driven Supernovae
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New simulations show how a dynamo in collapsed massive stars can build the strong magnetic fields needed to power extremely energetic blasts.

Dark Matter Dominates in Nearby Dwarf Galaxy

Dark matter is called "dark" for a good reason. Although they outweigh particles of regular matter by more than a factor of 5, particles of dark matter are elusive. Their existence is inferred by their gravitational influence in galaxies, but no one has ever directly observed signals from dark matter. Now, by measuring the mass of a nearby dwarf galaxy called Triangulum II, Assistant Professor of Astronomy Evan Kirby may have found the highest concentration of dark matter in any known galaxy.

Triangulum II is a small, faint galaxy at the edge of the Milky Way, made up of only about 1,000 stars. Kirby measured the mass of Triangulum II by examining the velocity of six stars whipping around the galaxy's center. "The galaxy is challenging to look at," he says. "Only six of its stars were luminous enough to see with the Keck telescope." By measuring these stars' velocity, Kirby could infer the gravitational force exerted on the stars and thereby determine the mass of the galaxy.

"The total mass I measured was much, much greater than the mass of the total number of stars—implying that there's a ton of densely packed dark matter contributing to the total mass," Kirby says. "The ratio of dark matter to luminous matter is the highest of any galaxy we know. After I had made my measurements, I was just thinking—wow."

Triangulum II could thus become a leading candidate for efforts to directly detect the signatures of dark matter. Certain particles of dark matter, called supersymmetric WIMPs (weakly interacting massive particles), will annihilate one another upon colliding and produce gamma rays that can then be detected from Earth.

While current theories predict that dark matter is producing gamma rays almost everywhere in the universe, detecting these particular signals among other galactic noises, like gamma rays emitted from pulsars, is a challenge. Triangulum II, on the other hand, is a very quiet galaxy. It lacks the gas and other material necessary to form stars, so it isn't forming new stars—astronomers call it "dead." Any gamma ray signals coming from colliding dark matter particles would theoretically be clearly visible.

It hasn't been definitively confirmed, though, that what Kirby measured is actually the total mass of the galaxy. Another group, led by researchers from the University of Strasbourg in France, measured the velocities of stars just outside Triangulum II and found that they are actually moving faster than the stars closer into the galaxy's center—the opposite of what's expected. This could suggest that the little galaxy is being pulled apart, or "tidally disrupted," by the Milky Way's gravity.

"My next steps are to make measurements to confirm that other group's findings," Kirby says. "If it turns out that those outer stars aren't actually moving faster than the inner ones, then the galaxy could be in what's called dynamic equilibrium. That would make it the most excellent candidate for detecting dark matter with gamma rays."

A paper describing this research appears in the November 17 issue of the Astrophysical Journal Letters. Judith Cohen (PhD '71), the Kate Van Nuys Page Professor of Astronomy, is a Caltech coauthor.

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Simon Receives Lifetime Achievement Award

Barry M. Simon, the International Business Machines (IBM) Professor of Mathematics and Theoretical Physics at Caltech, has been awarded the 2016 Leroy Steele Prize for Lifetime Achievement of the American Mathematical Society (AMS) for his "tremendous impact on the education and research of a whole generation of mathematical scientists through his significant research achievements, highly influential books, and mentoring of graduate students and postdocs," according to the prize citation.

In conferring the award, the AMS noted Simon's "career of exceptional achievement," which includes the publication of 333 papers and 16 books. Simon was specifically recognized for proving a number of fundamental results in statistical mechanics and for contributing to the construction of quantum fields in two space‐time dimensions—topics that, the AMS notes, have "grown into major industries"—as well as for his "definitive results" on the general theory of Schrödinger operators, work that is crucial to an understanding of quantum mechanics and that has led to diverse applications, from probability theory to theoretical physics. He has also made fundamental contributions to the theory of orthogonal polynomials and their asymptotics.

"Barry Simon is a powerhouse in mathematical physics and has had an outstanding career which this award attests to," says Vladimir Markovic, the John D. MacArthur Professor of Mathematics. "Caltech is lucky to have him."

"Barry is a driving force in mathematics at Caltech and has had enormous influence as a scholar, a teacher, and a mentor," says Fiona Harrison, the Benjamin M. Rosen Professor of Physics and holder of the Kent and Joyce Kresa Leadership Chair for the Division of Physics, Mathematics and Astronomy.

Simon spoke at the International Congress of Mathematics in 1974 and has since given almost every prestigious lecture available in mathematics and physics. He was named a fellow of the American Academy of Arts and Sciences in 2005, and was among the inaugural class of AMS fellows in 2012. In 2015, Simon was awarded the International János Bolyai Prize of Mathematics by the Hungarian Academy of Sciences, given every five years to honor internationally outstanding works in mathematics, and in 2012, he was given the Henri Poincaré Prize by the International Association of Mathematical Physics. The prize is awarded every three years in recognition of outstanding contributions in mathematical physics and accomplishments leading to novel developments in the field.

Simon received his AB from Harvard College in 1966 and his doctorate in physics from Princeton University in 1970. He held a joint appointment in the mathematics and physics departments at Princeton for the next decade. He first arrived at Caltech as a Sherman Fairchild Distinguished Visiting Scholar in 1980 and joined the faculty permanently in 1981. He became the IBM Professor in 1984.

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Two Caltech Alumni Receive Breakthrough Prize

Two Caltech alumni, Arthur McDonald (PhD '70) and Ian Agol (BS '92), have been named recipients of 2016 Breakthrough Prize awards. The prizes, which each carry a monetary award of $3 million, are given annually for achievements in mathematics and science to "encourage more pioneering research and celebrate scientists as the heroes they truly are," says Mark Zuckerberg, one of the prizes' founders.

The 2016 Breakthrough Prize in Fundamental Physics was awarded collectively to a community of more than 1,300 physicists who participated in five experiments investigating neutrinos, one of the most abundant particles in the known universe. McDonald—a 2015 Nobel laureate—was one of the seven scientists who led these experiments, heading the Sudbury Neutrino Observatory collaboration in Ontario. Neutrinos are unaffected by the two strong fundamental forces of nature—electromagnetism and the strong nuclear force—and are thus elusive, traveling through the universe essentially unimpeded and near the speed of light.

McDonald is currently Professor Emeritus at Queen's University and earlier this year shared the Nobel Prize in Physics for "the discovery of neutrino oscillations, which shows that neutrinos have mass."

Ian Agol received the 2016 Breakthrough Prize in Mathematics for his "spectacular contributions to low-dimensional topology and geometric group theory, including work on the solutions of the tameness, virtual Haken and virtual fibering conjectures." Low-dimensional topology is a field that focuses on manifolds—objects that seem flat when observed at a small scale—in four or fewer dimensions. Earth is one example of a manifold—while it is actually spherical, we humans are too small to be able to perceive Earth's curvature, and thus Earth appears flat to us.

Agol is a professor of mathematics at UC Berkeley and is currently a visiting researcher at the Institute for Advanced Study in Princeton, New Jersey.

The Breakthrough Prize was founded by Sergey Brin of Google, and Anne Wojcicki of 23andMe; Jack Ma of Alibaba, and Cathy Zhang; Yuri Milner, a venture capitalist and physicist, and Julia Milner; and Mark Zuckerberg of Facebook, and Priscilla Chan. The awards were presented at a ceremony in San Francisco on November 8.

Previous Caltech winners include Alexei Kitaev, the Ronald and Maxine Linde Professor of Theoretical Physics and Mathematics, and John H. Schwarz, the Harold Brown Professor of Theoretical Physics, Emeritus, who won the Fundamental Physics prize in 2012 and 2014 respectively. Alexander Varshavsky, the Howard and Gwen Laurie Smits Professor of Cell Biology, received the Breakthrough Prize in Life Sciences in 2014.

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Arthur McDonald (PhD '70) and Ian Agol (BS '92), have been named recipients of 2016 Breakthrough Prize awards.
Monday, November 30, 2015

Microbial diners, drive-ins, and dives: deep-sea edition

Celebrating 50 Years of Infrared Astronomy

A Milestone in Astronomy

Fifty years ago, a group of Caltech physicists brought infrared light—then an underappreciated region of the electromagnetic spectrum—to the forefront of astrophysics. Infrared astronomy holds the keys to our cosmic origins, revealing how planets, stars, and even the earliest galaxies formed. It may even enable us to discover Earth-like planets orbiting other stars.

The clouds of dust and gas from which stars and planets form—and the newborn solar systems themselves—are too cold to be seen in visible light. However, the heat they do emit shows up in the infrared, the shortest wavelengths of which are just slightly longer than the red light we do see.  The earliest galaxies would be visible, if they were closer to us in space and time; instead, the expanding universe has stretched their light so that the wavelengths are shifted down into the infrared. However, most of this light never reaches earthbound telescopes, as Earth's atmosphere absorbs most infrared waves very efficiently.

Two next-generation space telescopes, the James Webb Space Telescope, which is slated to launch in October 2018 to replace the Hubble Space Telescope, and the Wide-Field Infrared Survey Telescope (WFIRST), which has been named a top priority for the next decade in astronomy and is being studied for launch in the mid-2020s, will be carrying forward work begun by the Infrared Astronomical Satellite (IRAS) mission in the 1980s—work in which Caltech's self-styled "Infrared Army" played a major role.

On November 2 and 3, 2015, Caltech hosted a two-day symposium in honor of the Army's three founders—the late Gerry Neugebauer (PhD '60), Caltech's Robert Andrews Millikan Professor of Physics, Emeritus; Tom Soifer (BS '68), the Harold Brown Professor of Physics and director of the Spitzer Science Center, which operates NASA's current orbiting infrared observatory, the Spitzer Space Telescope; and Keith Matthews (BS '62), chief instrument scientist for Palomar Observatory, who by his own estimation has built "scores" of instruments for the 5-meter Hale telescope at Palomar and the twin 10-meter telescopes at the W. M. Keck Observatory atop Mauna Kea, Hawaii.

Matthews' hardware output is rivaled by the rate at which Neugebauer's and Soifer's research groups have spun off infrared programs at other institutions. Says organizer Lee Armus, who arrived at Caltech as a postdoc of Soifer's in 1992, "I've got a group of grad students from the '70s and '80s, and a group from the '90s. I'm trying to sample as many epochs as I can in two days."

Neugebauer earned his doctorate in 1960 under Caltech physics professor Robert Lee Walker, who had codesigned Caltech's synchrotronthe most powerful machine of its kind in its day, capable of revving up an electron to a billion volts of energy. In those days, experimental physicists built and operated their own equipment—and thus understood it inside and out. Neugebauer brought this hands-on approach to the U.S. Army at Caltech's Jet Propulsion Lab, where he designed and operated the infrared radiometer for Mariner 2's successful flyby of Venus.

When Neugebauer returned to campus in 1962, he and fellow physics professor Robert Leighton (BS '41, PhD '47) set about making the 62-inch-diameter mirror for the world's first purpose-built infrared telescope. (It is now in the Smithsonian.) Over the next few years, they and a team of undergraduates and graduate students used the instrument to scan the entire sky—or as much as could be seen from the summit of Mount Wilson overlooking Pasadena. The Two-Micron Sky Survey's final catalog, published in 1969, inventoried some 5,000 point-like objects, many of which were previously undiscovered cool red stars or stars enshrouded in obscuring clouds of gas and dust that the stars had ejected as they entered the later stages of their life.

Other invisible objects also cropped up. In 1965, Neugebauer's first graduate student, Eric Becklin (PhD '68) discovered something in the Orion Nebula that, in the infrared, was as bright as the brightest visible star, except it had no visible counterpart. Follow-up work with the 200-inch Hale Telescope at Palomar revealed that this point of infrared light had faint "wings," about 15 times larger than its diameter, extending to its east and west—a feature unlike any ever seen before. The Orion Nebula was known to be at most a few million years old and was presumed to be a stellar nursery. The object Becklin detected was the first protostar to be caught in its shell of potentially planet-forming dust. Becklin would later pioneer high-altitude infrared astronomy aboard specially modified jet aircraft.

In the 1970s Neugebauer and Soifer became part of the science team for IRAS, a collaboration among the United States, England, and the Netherlands. Launched in 1983, IRAS surveyed more than 95 percent of the sky. The data were made available to the entire scientific community as soon as they were processed—a first for NASA—leading to the creation of Caltech's Infrared Processing and Analysis Center to curate and distribute it.


3D Movie of Stellar Orbits in the Central Parsec
Tracking the stars in close orbit around the center of our galaxy reveals the existence of a black hole containing four million times the mass of our sun. This 3-D orbital reconstruction begins in the year 1893 at the galactic center, about 0.05 light years from the supermassive black hole, and pulls back to end at a distance of 0.65 light years in the year 2013. Young stars are shown in teal green, old stars are shown in orange, and those of unknown spectral type are shown in magenta.

IRAS got the field of infrared astronomy off the ground. "Astronomers could trust our catalogs," Soifer says. "Every source was real. We gained the respect of the astronomical community because they could take some other telescope and point it at our coordinates, and they'd find really interesting objects to explore with millimeter telescopes, radio telescopes, optical telescopes."

Matthews "started working in cosmic rays in 1959 with Professor of Physics [Eugene] 'Bud' Cowan [PhD '48]," and still sees himself as a physicist. "I do anything that has technique to it," he says. In addition to helping design the infrared aspects of the Keck 10-meter telescopes, he built the observatory's Near-Infrared Camera, the first instrument to be mounted on the telescope.

In the early 1990s Andrea Ghez (MS '89, PhD '93), one of Neugebauer's last graduate students, used this instrument and a technique called "speckle interferometry" to measure the positions of stars close to the galactic center. Ghez now uses the telescopes as the founder and director of UCLA's Galactic Center Group. Nearly two decades' worth of measurements, mostly using the second- generation Near-Infrared Camera for the Keck II telescope built by Matthews, have allowed her to derive radial velocities of stars as they orbit that still-elusive black hole. Thanks to her work, however, the mass of our galaxy's black hole is now precisely known, making it a little less mysterious.

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Celebrating 50 Years of Infrared Astronomy
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Fifty years ago, Caltech and its self-styled Infrared Army of experimental physicists and astronomers helped to found the discipline of infrared astronomy

Elachi to Retire as JPL Director

Charles Elachi (MS '69, PhD '71) has announced his intention to retire as director of the Jet Propulsion Laboratory on June 30, 2016, and move to campus as professor emeritus. A national search is underway to identify his successor.

"A frequently consulted national and international expert on space science, Charles is known for his broad expertise, boundless energy, conceptual acuity, and deep devotion to JPL, campus, and NASA," said Caltech president Thomas F. Rosenbaum in a statement to the Caltech community. "Over the course of his 45-year career at JPL, Charles has tirelessly pursued new opportunities, enhanced the Laboratory, and demonstrated expert and nimble leadership. Under Charles' leadership over the last 15 years, JPL has become a prized performer in the NASA system and is widely regarded as a model for conceiving and implementing robotic space science missions."

With Elachi at JPL's helm, an array of missions has provided new understanding of our planet, our moon, our sun, our solar system, and the larger universe. The GRAIL mission mapped the moon's gravity; the Genesis space probe returned to Earth samples of the solar wind; Deep Impact intentionally collided with a comet; Dawn pioneered the use of ion propulsion to visit the asteroids Ceres and Vesta; and Voyager became the first human-made object to reach interstellar space. A suite of missions to Mars, from orbiters to the rovers Spirit, Opportunity, and Curiosity, has provided exquisite detail of the red planet; Cassini continues its exploration of Saturn and its moons; and the Juno spacecraft, en route to a July 2016 rendezvous, promises to provide new insights about Jupiter. Missions such as the Galaxy Evolution Explorer, the Spitzer Space Telescope, Kepler, WISE, and NuSTAR have revolutionized our understanding of our place in the universe.

Future JPL missions developed under Elachi's guidance include Mars 2020, Europa Clipper, the Asteroid Redirect Mission, Jason 3, Aquarius, OCO-2, SWOT, and NISAR.

Elachi joined JPL in 1970 as a student intern and was appointed director and Caltech vice president in 2001. During his more than four decades at JPL, he led a team that pioneered the use of space-based radar imaging of the Earth and the planets, served as principal investigator on a number of NASA-sponsored studies and flight projects, authored more than 230 publications in the fields of active microwave remote sensing and electromagnetic theory, received several patents, and became the director for space and earth science missions and instruments. At Caltech, he taught a course on the physics of remote sensing for nearly 20 years

Born in Lebanon, Elachi received his B.Sc. ('68) in physics from University of Grenoble, France and the Dipl. Ing. ('68) in engineering from the Polytechnic Institute, Grenoble. In addition to his MS and PhD degrees in electrical science from Caltech, he also holds an MBA from the University of Southern California and a master's degree in geology from UCLA.

Elachi was elected to the National Academy of Engineering in 1989 and is the recipient of numerous other awards including an honorary doctorate from the American University of Beirut (2013), the National Academy of Engineering Arthur M. Bueche Award (2011), the Chevalier de la Légion d'Honneur from the French Republic (2011), the American Institute of Aeronautics and Astronautics Carl Sagan Award (2011), the Royal Society of London Massey Award (2006), the Lebanon Order of Cedars (2006 and 2012), the International von Kármán Wings Award (2007), the American Astronautical Society Space Flight Award (2005), the NASA Outstanding Leadership Medal (2004, 2002, 1994), and the NASA Distinguished Service Medal (1999).

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He will move to campus as professor emeritus. A national search is underway to identify his successor.

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