Gerry Neugebauer: Pioneer of infrared astronomy

Sometime near the end of 2018, National Aeronautics and Space Administration (NASA) will launch the James Webb Space Telescope (JWST). This “mega” space infrared observatory builds on decades of extremely successful space infrared astronomy missions and infrared instruments for ground-based telescopes that have provided new insights into an otherwise hidden universe. None of this would have been possible if not for the groundbreaking efforts of the handful of physicists who created the field of infrared astronomy and convinced the astronomical community of its promise. Standing as the leader of this pioneering group was Gerry Neugebauer (1932–2014)

Gerry Neugebauer - 1932–2014

Gerry Neugebauer was one of a small band of experimental physicists who used their perspectives to create a new discipline within astrophysics. Together they founded what is now known as infrared astronomy. Gerry’s commitment to innovative instruments and sky surveys exploring the unknown universe was matched by his commitment to the highest quality of published and archived data, which were vital to the creation of a dominant discipline in modern observational astrophysics. His discovery of many new kinds of celestial objects and phenomena, studies of which have remained vibrant subfields of astrophysics to this day, brought many others into the field that he helped invent. Neugebauer did his undergraduate study at Cornell University and earned a Ph.D. from the California Institute of Technology (Caltech). After receiving his doctorate, he spent two years at the Jet Propulsion Laboratory in performance of his military obligation as a reserve officer, working on the Mariner 2 Spacecraft project. He then joined the Caltech faculty and remained there in successively higher positions, eventually becoming chairman of the Division of Physics, Mathematics and Astronomy, as well as director of the Palomar Observatory

Extremely Luminous Far-infrared Sources (ELFS)

The Infrared Astronomical Satellite (IRAS) survey uncovered a class of Extremely Luminous Far Infrared Sources (ELFS), exhibiting luminosities up to and occasionally exceeding 10 to the 12th power L sub 0. Arguments are presented to show that sources with luminosities L equal to or greater than 3 x 10 to the 10th power L sub 0 may represent gas rich galaxies in collision. The more conventional explanation of these sources as sites of extremely active star formation fails to explain the observed low optical luminosities of ELFS as well as their high infrared excess. In contrast, a collisional model heats gas to a temperature of approx. 10 to the 6th power K where cooling takes place in the extreme ultraviolet. The UV is absorbed by dust and converted into far infrared radiation (FIR) without generation of appreciable optical luminosity. Gas recombination as it cools generates a Lyman alpha photon only once for every two extreme ultraviolet approx. 50eV photons emitted by the 10 to the 6th power gas. That accounts for the high infrared excess. Finally, the model also is able to explain the observed luminosity distribution of ELFS as well as many other traits

GOALS-JWST: Hidden Star Formation and Extended PAH Emission in the Luminous Infrared Galaxy VV 114

James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) images of the luminous infrared (IR) galaxy VV 114 are presented. This redshift ∼0.020 merger has a western component (VV 114W) rich in optical star clusters and an eastern component (VV 114E) hosting a luminous mid-IR nucleus hidden at UV and optical wavelengths by dust lanes. With MIRI, the VV 114E nucleus resolves primarily into bright NE and SW cores separated by 630 pc. This nucleus comprises 45% of the 15 μm light of VV 114, with the NE and SW cores having IR luminosities, L IR(8 − 1000 μm) ∼ 8 \ub1 0.8 7 1010 L ⊙ and ∼ 5 \ub1 0.5 7 1010 L ⊙, respectively, and IR densities, ΣIR ≳ 2 \ub1 0.2 7 1013 L ⊙ kpc−2 and ≳ 7 \ub1 0.7 7 1012 L ⊙ kpc−2, respectively—in the range of ΣIR for the Orion star-forming core and the nuclei of Arp 220. The NE core, previously speculated to have an active galactic nucleus (AGN), has starburst-like mid-IR colors. In contrast, the VV 114E SW core has AGN-like colors. Approximately 40 star-forming knots with L IR ∼ 0.02-5 7 1010 L ⊙ are identified, 28% of which have no optical counterpart. Finally, diffuse emission accounts for 40%-60% of the mid-IR emission. Mostly notably, filamentary polycyclic aromatic hydrocarbon (PAH) emission stochastically excited by UV and optical photons accounts for half of the 7.7 μm light of VV 114. This study illustrates the ability of JWST to detect obscured compact activity and distributed PAH emission in the most extreme starburst galaxies in the local universe

A review of elliptical and disc galaxy structure, and modern scaling laws

A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their models to describe the radial distribution of stars in `nebulae'. This article reviews the progress since then, providing both an historical perspective and a contemporary review of the stellar structure of bulges, discs and elliptical galaxies. The quantification of galaxy nuclei, such as central mass deficits and excess nuclear light, plus the structure of dark matter halos and cD galaxy envelopes, are discussed. Issues pertaining to spiral galaxies including dust, bulge-to-disc ratios, bulgeless galaxies, bars and the identification of pseudobulges are also reviewed. An array of modern scaling relations involving sizes, luminosities, surface brightnesses and stellar concentrations are presented, many of which are shown to be curved. These 'redshift zero' relations not only quantify the behavior and nature of galaxies in the Universe today, but are the modern benchmark for evolutionary studies of galaxies, whether based on observations, N-body-simulations or semi-analytical modelling. For example, it is shown that some of the recently discovered compact elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to appear in "Planets, Stars and Stellar Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references incl. many somewhat forgotten, pioneer papers. Original submission to Springer: 07-June-201

On the Density of Sets Avoiding Parallelohedron Distance 1

The maximal density of a measurable subset of R^n avoiding Euclidean distance1 is unknown except in the trivial case of dimension 1. In this paper, we consider thecase of a distance associated to a polytope that tiles space, where it is likely that the setsavoiding distance 1 are of maximal density 2^-n, as conjectured by Bachoc and Robins. We prove that this is true for n = 2, and for the Vorono\"i regions of the lattices An, n >= 2.Initiative d'excellence de l'Université de Bordeau

MIPS J142824.0+352619: A Hyperluminous Starburst Galaxy at z = 1.325

International audienceUsing the SHARC-II camera at the Caltech Submillimeter Observatory to obtain 350 mum images of sources detected with the MIPS instrument on Spitzer, we have discovered a remarkable object at z=1.325+/-0.002 with an apparent far-infrared luminosity of 3.2(+/-0.7)×1013 Lsolar. Unlike other z>1 sources of comparable luminosity selected from mid-IR surveys, MIPS J142824.0+352619 lacks any trace of AGN activity, and is likely a luminous analog of galaxies selected locally by IRAS, or at high redshift in the submillimeter. This source appears to be lensed by a foreground elliptical galaxy at z=1.034, although the amplification is likely modest