RETROSPECTIVE Gerry Neugebauer: Pioneer of infrared astronomy B. Thomas Soifer1 Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125

Sometime near the end of 2018, National supportive style, as Gerry worked closely Aeronautics and Space Administration with his students to build a unique telescope (NASA) will launch the James Webb Space and instrument to explore the universe at Telescope (JWST). This “mega” space in- previously unseen wavelengths. The results frared observatory builds on decades of ex- of the TMSS clearly demonstrated that tremely successful space infrared astron- many unanticipated yet extraordinary phe- omy missions and infrared instruments for nomena were at work and even common in ground-based telescopes that have provided the cosmos, lighting up the heavens with new insights into an otherwise hidden uni- bright objects observable only in the infra- verse. None of this would have been possi- red. This groundbreaking survey, coupled ble if not for the groundbreaking efforts with other advances in the field, triggered of the handful of physicists who created the explosive development of infrared as- the field of infrared astronomy and con- tronomy in the 1970s and 1980s. vinced the astronomical community of its Gerry’s so-called “infrared army”—consist- promise. Standing as the leader of this pio- ing of himself, one or two postdocs, and three neering group was Gerry Neugebauer or four graduate students and a number of Gerry Neugebauer. Image courtesy of the – — (1932 2014). undergraduates was legendary at Caltech Caltech Archives. Gerry was born in Gottingen, Germany, in for its hard work, excitement in observing, 1932. Fleeing the Nazis, his family relocated and infectious delight on each new discovery. first to Copenhagen in 1933 and then, in His group (I was among them, first as a Cal- because the energy absorbed by dust in 1939, moved to Providence, RI, when his tech undergrad, later as a postdoc, and ulti- circumstellar environments heats the material father, the noted historian of mathematics mately as Gerry’s successor) built infrared to hundreds of degrees Kelvin, creating espe- Otto Neugebauer, took a position at Brown instruments for ground-based optical tele- cially bright sources of infrared radiation. University. Gerry received his undergraduate scopes. We were happy to exploit observing In the mid-1970s, Gerry became the co- physics education at Cornell University, windows that “real” astronomers disdained— leader, with Reinder van Duinen and then followed by graduate work in high-energy thatis,whenthemoonwasfull.Histeam’s Harm Habing, of an American-Dutch-British physics at Caltech. After receiving his PhD efforts led to a continual stream of amazing science team that was formed to lead the in 1960, he was assigned to the nearby Jet new phenomena in the heavens. Infrared Astronomy Satellite (IRAS) mission. Propulsion Laboratory for military service In addition to the revolutionary work of IRAS performed the first all-sky infrared [he had been in the Reserve Officers’ Train- the TMSS, Gerry and his collaborators made survey at far-infrared wavelengths, from 12 ing Corps (ROTC) in college]. There, he many other discoveries. With his student, to 100 μm. Gerry’s technical contributions worked on the infrared experiment on Mar- Eric Becklin, he originated the study of star and leadership led to a resoundingly success- iner 2, which, when it passed by Venus, be- formation at infrared wavelengths by finding ful launch in 1983. The one-year survey mis- came the first satellite to successfully explore the Becklin–Neugebauer object, the first sion guided the field and continues to have ’ another world. (His wife, the prominent “protostar”—a star in the earliest stages of a major impact on astronomy. Two of IRAS s — space physicist Marcia Neugebauer, also evolution. Again with Becklin, he located at significant scientific discoveries the first di- worked on Mariner 2, providing the first the wavelength of 2 μm the center of our rect detection of planetary debris disks and direct measurements of the solar wind.) galaxy and made many seminal discoveries the discovery that exceedingly dusty, lumi- In 1962, after his military service ended, in this unique patch of sky. nous galaxies were common in the nearby — he returned as an assistant professor to These early discoveries highlight a major universe continue to inspire research today. Caltech, where he remained for the rest of theme of the field: the profound influence Neugebauer was directly involved in both. his professional career. of interstellar and circumstellar dust on our His enjoyment in discovery was matched In the 1960s, with his colleague Bob view of the universe. Such dust, found in by his pleasure at mentoring students and Leighton, Gerry conducted the very first association with individual objects and scat- postdocs, treating all as peers; referring to sky survey at infrared wavelengths. At the tered throughout interstellar space, obscures his experimental physics roots, he proudly time, a “big science” project (at least for our view much more effectively at visible astronomy), the Two-Micron Sky Survey wavelengths; in the infrared, it is as if the dust Author contributions: B.T.S. wrote the paper. (TMSS), exemplified his collaborative and is swept away. Our view is further enhanced 1Email: [email protected].

17342–17343 | PNAS | December 9, 2014 | vol. 111 | no. 49 www.pnas.org/cgi/doi/10.1073/pnas.1420292111 Downloaded by guest on September 24, 2021 called himself a “plumber.” Known to ev- Later in his career, Gerry served Caltech decades of his life, he suffered, with courage RETROSPECTIVE eryone simply as Gerry, and as GXN to his as the Director of the Palomar Observatory and good spirits, the debilitating effects of friends (he had no middle name and the X from 1980 to 1994 and as the Chairman of spinocerebellar ataxia, a neurodegenerative was imposed on him by the Caltech com- the Division of Physics, Mathematics, and disease. Gerry passed away on September 26 puter center when accounts required three Astronomy from 1988 to 1993. He was also fromcomplicationsofthisdisease.Thespirit letters), he was immediately recognizable deeply involved in the building of the Keck of exploration and discovery with which he around the Caltech campus in his uniform: Observatory on Mauna Kea, HI. helped to open the infrared window on the a blue oxford shirt and khaki shorts that he He retired in 1998 and moved with Marcia universelivesoninthegenerationsofstu- wore even in the depths of winter. to Tucson, AZ, in 2002. For the last two dents (and colleagues) he inspired.

Soifer PNAS | December 9, 2014 | vol. 111 | no. 49 | 17343 Downloaded by guest on September 24, 2021