for his contributions to astronomy in the infrared to submillimetre spectral range. He detected the cosmic far-infrared background from past star-forming galaxies, and proposed aromatic hydrocarbon molecules as a constituent of interstellar matter. With the Planck space mission, he has dramatically advanced our knowledge of cosmology in the presence of interstellar matter foregrounds.
The Shaw Prize in Astronomy 2018 is awarded to Jean-Loup Puget, of the Institut d’Astrophysique Spatiale (IAS) of CNRS and the University of Paris-Sud 11 for his contributions to astronomy in the infrared to submillimeter spectral range. He detected the cosmic far-infrared background from past star-forming galaxies, and proposed aromatic hydrocarbon molecules as a constituent of interstellar matter. With the Planck space mission, for which he is the Principal Investigator of the High Frequency Instrument (HFI), he has dramatically advanced our knowledge of cosmology in the presence of interstellar matter foregrounds.
The infrared-to-submillimetre spectral range offers a unique window on the universe. Such radiation can pierce the obscuring material in the interstellar medium, while also probing the nature of that material. The longest wavelengths within this range, near 1 mm, also give information on conditions when the universe was around 400,000 years old, via the cosmic microwave background (CMB). Jean-Loup Puget has made pivotal contributions to all these areas.
The infrared-to-millimetre spectral range (1 to 10,000 μm) offers a unique and little explored window on the Universe. Such radiation probes cold, dusty objects such as dense interstellar material, forming stars, and obscured young galaxies. The longest wavelengths, near a few millimetres, also give information on conditions when the Universe was around 400,000 years old, via the Cosmic Microwave Background (CMB). To detect the faint cosmic signals in this waveband in the presence of very large instrumental, atmospheric and astronomical foreground radiation is challenging. It requires special cryogenic sensors, and optimized telescopes above the Earth’s atmosphere and in space. Jean-Loup Puget has made pivotal contributions to all these aspects, scientific as well as technical.
In the 1970s and early 1980s mysterious spectral emission features between 3 and 12 μm were discovered in Galactic reflection nebulae. Léger & Puget (1984) and independently Allamandola, Tielens and Barker (1985) proposed that these puzzling features come from large “polycyclic aromatic hydrocarbon” (PAH) molecules, similar to car exhaust, and composed mainly of carbon-hydrogen rings. The PAHs represent a new form of interstellar “dust”. Dust grains and PAHs are heated when they absorb ultraviolet radiation from massive stars. They re-emit this energy as a grey-body thermal continuum in the infrared-submillimetre band and as PAH features. The total intensity of such emission measures cosmic star formation, integrated over the entire history of the Universe. In 1996 Puget and co-workers discovered in data of the NASA COBE satellite a pervasive 100 μm background radiation plausibly from an active star formation phase about 10 billion years ago. Many infrared measurements have since confirmed this discovery and shown that this was the epoch when most of stars in galaxies were formed.
Jean-Loup Puget was born in 1947 in Chalon-sur-Saône, Saône-et-Loire, France and is currently a researcher at the Institut d’Astrophysique Spatiale (IAS) of CNRS and the University of Paris-Sud 11. He is also the Principal Investigator of the High Frequency Instrument (HFI) of the Planck Mission of the European Space Agency. He studied at Ecole normale supérieure de Cachan, France in 1966–1970 and received his PhD in 1973. From 1973, he was a Researcher and Director of Research at the National Center for Scientific Research in France. He served as Deputy Director of the Institute of Astrophysics of Paris from 1978 to 1982. He then joined IAS in Orsay, where he was successively Deputy Director (1990–1997) and Director (1998–2005). He is a member of the Académie des sciences (France).
