Tal Alexander had an association with our faculty from his birth in Rehovot in 1963, as his father, Gideon Alexander, was at the time a member of our faculty. After Tal’s discharge from the 8200 unit in the IDF, Tal enrolled at the Hebrew University where he completed his B.Sc. studies in Physics and Mathematics in 1989. Tal then moved to Tel Aviv University where he completed his PhD studies in astrophysics under the guidance of Hagai Netzer, and received his degree in 1997. He then spent a year as a Postdoctoral Fellow at the Max Planck Institut fuer Extraterrestrische Physik, Munich, after which he spent a year as a member at the Institute for Advanced Study, Princeton. The next year Tal was a postdoctoral fellow at the Space Telescope Science Institute, in Baltimore. In 2001, Tal returned to Israel, to start his research at the Weizmann Institute, first as a Senior Scientist, and then, from 2008 until his untimely death in 2018, as an Associate Professor.
In 2007, Tal received the European Research Council Starting Grant, and the Wolf Foundation Krill Prize for Excellence in Scientific Research.
Tal served as the head of the Department of Particle Physics and Astrophysics from April 15, 2012 until April 30, 2017.
Tal’s research revolved mainly around the massive black holes at the centers of galaxies. Starting in his PhD work and his first years as a postdoctoral fellow, Tal has contributed to our understanding to phenomena observed around active galactic nuclei, powered by such black holes, in particular to questions related to the time variability of the observed radiation from such sources. Later on, Tal’s research concentrated on the dynamics of stars in such galactic nuclei, on the formation and evolution of accretion disks around the black hole, and on the star-black-hole systems as possible sources of gravitational wave. Among his other contributions, Tal took and active part, within Reinhard Genzel’s group, in the discovery of S2 – the first star shown to complete an orbit around the black hole at the center of our Galaxy. Inspired by this important discovery, Tal calculated and put forth predictions of the observability of general-relativistic effects in the orbit of S2 when it will have come nearest the black hole. His predictions where verified observationally in mid 2018, when, as expected, S2 was reaching its shortest distance from the black hole. Alas, Tal was not with us to enjoy his triumph, as he passed away only a short time earlier.
Tal was survived by his wife Nava Pinchuk-Alexander, and by his children, Yotam and Noa.