Yoram Avni was born in Tel Aviv in 1945. After completing his undergraduate studies at the Hebrew University in 1965, he came to our faculty as a student. After completing his M.Sc., Yoram embarked on PhD studies in theoretical particle physics under Haim Harari.

In 1972, Yoram went to SLAC as a postdoc in particle physics, but a year later, he switched fields, as part of the move to establish a group of theoretical astrophysics at the faculty. He thus went in 1972 to the Institute for Advanced Study in Princeton to work with the late John Bahcall on x-ray astrophysics. Yoram returned to the faculty in 1974 to establish with others the astrophysics group, and became a tenured associate professor in 1978, and a professor a few years later. While based at the Weizmann Institute, Yoram held many visiting positions, at the Institute in Princeton, at MIT, at the Institute of Astronomy in Cambridge UK, and at the Harvard-Smithsonian Center for Astrophysics, where he moved permanently in 1984.

Yoram died in March 1988 , at the age of 43, after a short illness.

In the first few years of his career in astrophysics Yoram worked on the astrophysics of x-ray binary stars, where one of the component stars is a compact object – a neutron star or a black hole. Towards the late 1970s, Yoram’s main interests shifted to the studies of statistical characterization of populations of astronomical objects, such as x-ray sources, galaxy clusters, but especially of quasars, with a view to learn, for example, about the cosmological, time evolution of the population.

Yoram also invented a most useful statistical method, to combine, for analysis, samples of objects that were selected under different criteria (such as detection threshold), or of catalogs of objects that were observed at different wavelengths. The method he invented helped for example, discover unsuspected relations between the emissivity of quasars in the optical and x-rays, and to estimate the contribution of individual quasars to the cosmological x-ray background.

Yoram was survived by his wife Nitza, and sons Joel and Ron.