Lawrence H. Auer

United States

1941-2023

Obituary:

It is with sadness that we recently learned of the passing of Lawrence H. Auer (Dec. 7, 1941 - Jan. 13, 2023). Larry Auer is a pioneer of non-LTE radiative transfer. The methods developed by him during the 1970s, mostly in collaboration with Dimitri Mihalas, led to a breakthrough in the realistic description of non-equilibrium radiative transfer and model atmospheres and they became a fundamental tool for the quantitative spectral analysis of stellar spectra. In a series of landmark papers he introduced the method of complete linearization. The application of this method to a wide range of stellar spectra demonstrated the crucial importance of non-LTE effects for their interpretation. In collaboration with G. Olson and J. R. Buchler they published the seminal study on the Accelerated Lambda-Iteration method with a diagonal operator, and with P. Kunasz he invented the method known as "short characteristics" which opened a vast pathway to modeling radiative transfer in multi-dimensional geometry. It is fair to say that Larry Auer’s contributions laid the foundation for the precision spectroscopy of today.
After his undergraduate studies at Haverford College, Larry Auer went on to Princeton where he obtained his PhD degree. During the 1970s he worked at Yale University and at the National Center for Atmospheric Research (NCAR/HAO). Between 1980 and 1982 he was a professor at Penn State University where, with his student G. Koenigsberger, he became involved in the study of hot and massive stars of the Wolf-Rayet type using the International Ultraviolet Explorer space telescope. From 1982 until his retirement he worked at Los Alamos National Laboratory where he worked with G. A. Glatzmaier and others on potential phenomena related to a nuclear winter, with E.M Standish on astronomical refraction, and with his student F. Paletou on multi-dimensional radiative transfer problems.
A digital genius, Larry Auer developed algorithms for the massively parallel Connection Machine, and during the 1970s he developed his word editor called ABE (A Better Editor!) as well as his own Fortran pre-processor and graphics library.
Larry Auer is survived by his wife Kathlyn, who became his assistant and constant companion after the 1978 automobile accident that left him severely disabled.

From Gloria Koenigsberger (Universidad Nacional Autónoma de México) and Frédéric Paletou (U. Toulouse, OMP, France)