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Senior Research Scientist, UCL

My early work was done in Utrecht, and revolved around the atmosphere of the Sun, and stars, where radiative transport models were used and I studied what they implied. I also studied the dynamics of the chromosphere/corona interface in magnetic confined structures, like loops. Later, while at NASA/Goddard I extended my work to study of the eruptions of solar flares.
For some years I managed the NASA astronomical data and information efforts, and worked in engineering for remote sensing missions. I worked a year as a math and physics teacher. In recent times I worked on the calibration of one of the MSSL instruments on the SOHO mission, and since then calibrating the Swift UltraViolet and Optical Telescope which allowed a major jump in the understanding of gamma ray bursts and the eruptions of other event in the universe. Last year we were the first to observe the unexpected ultraviolet emission from the merger of two neutron stars that were found by the gravitational wave observatories. The "normal" events like supernovae and nova eruptions seem tame compared to those new discoveries. The discovery of events where it is unambiguous that a star is disrupted by a black hole (named TDEs) several years ago now finds many more of those. I write about the calibration of the UVOT instrument and work with many others on the study of the eruptive variables that we discover, as well as preparing for the new field of gravitational wave astronomy.


  • –present
    Senior Research Scientist, UCL


  • 1982 
    Sterrenkundig Instituut, Rijksuniversiteit Utrecht, Nederland, Astronomy and Astrophysics