NEIL GEHRELS: 3 OCTOBER 1952 - 6 FEBRUARY 2017

Neil and INTEGRAL: a man of the first hour

With his profound scientific knowledge and his experience managing complex space science projects, Neil provided invaluable support to the design and development of the INTEGRAL observatory mission from the first day onwards. Nuclear spectroscopy with GRIS and NAE, technology development of high-resolution Germanium detectors and his experience as Project Scientist of NASA's Compton Gamma-Ray Observatory were key contributions to the development of the INTEGRAL observatory mission. Neil served as a member of the ESA science study teams during the early Assessment Phase in 1990/91 and during the Phase A 1992/1993. After selection of the INTEGRAL mission by ESA in 1993, he was appointed Mission Scientist, representing NASA and the US high-energy astrophysics community, as early as 1995. From that point onwards, he continuously served, for more than 20 years, as a member of the INTEGRAL Science Working Team, which became later the INTEGRAL Users Group (see image). Among the various tasks which were taken up by Neil was the creation and maintenance of the INTEGRAL US Guest Observer Facility established at HEASARC/GSFC and his key contributions during the design and development of the Core Observing Programme of the INTEGRAL Mission.

His ideas, scientific advice, contributions and critical reviews through all phases of the mission development, were of great value and importance for the mission.

We will miss Neil. A very kind and very dear colleague and a great high-energy astrophysicist.

IUG Meeting #5, 15+16 November 2007, ESTEC, Noordwijk, The Netherlands