University of Amsterdam
        Ph. D. Astrophysics, 1994 (Thesis Advisor: Prof. Dr. Teije de Jong)
        Ph. D. Thesis: Dust and Ionized Gas in Elliptical Galaxies

Leiden University
        M. Sc. Astronomy, 1988

Observational studies of galaxy assembly and evolution. Properties of star clusters in galaxies along the Hubble sequence. Assembly history of early-type galaxies and bulges of spiral galaxies. Stellar Populations in external galaxies. The multi-phase ISM in early-type galaxies. Formation and evolution of globular clusters and globular cluster systems. The nature of multiple stellar populations in star clusters. Simulation of astronomical data. Optimization of instrument calibration. Building analysis pipelines of astronomical software.

My list of refereed publications

Research Positions

2020 - present     Observatory Scientist, STScI
2007 - 2020        (Full) Scientist, STScI

 JWST/NIRISS Deputy Branch Lead (Feb 2019 - present)
 JWST Cross-Instrument Operations Working Group Lead (Oct 2014 - present)
 JWST/NIRISS Instrument Scientist, Operations Lead (Nov 2011 - present)
 Sabbatical leave (Nov 2010 - Oct 2011)
 IT Project Scientist (Feb 2007 - Oct 2010)
 SM4/SMOV Instrument Scientist for COS and STIS (Oct 2008 - Feb 2010)
 Deputy Project Manager, Centralized Storage and Network Upgrade Implementation Team (Feb 2007 - Jan 2008)

2002 - 2007           Associate Scientist, STScI

Lead, STIS team at STScI (2004 - 2007)
Lead, HST Spectrographs Branch at STScI (2001-2004)

1996 - 2002           Assistant Astronomer, European Space Agency at STScI

STIS Instrument Scientist, Calibration Lead (2000-2001)
STIS Instrument Scientist, Servicing Mission 3A Lead (1998-2000)
STIS Instrument Scientist, CCD Calibration Specialist (1996-1998)

1994 - 1996           Postdoctoral Fellowship, European Southern Observatory
1988 - 1994           Research Associate, Astronomical Institute "Anton Pannekoek", University of Amsterdam

2019 - present        Member, STScI Science Personnel Committee
2017 - present        Member, STScI Research Computing Forum
2017 - 2018            Member, SOC, 2018 STScI Spring Symposium The 21st Century H-R Diagram: The Power of Precision Photometry
2015 - 2016            Member, STScI Staff Science Evaluation Committee
2015                       Chair, LOC & SOC, STScI Workshop The Stellar IMF at Low Masses: A Critical Look at Variations and Environmental Dependencies
2014                       Panel Member, Chandra TAC
Since 2011             External Reviewer for Tenure cases
2010                       Member, LOC & SOC, STScI May Symposium Stellar Populations in the Cosmological Context
2010                       Member, NSF Proposal Review Panel
Since 2009             External (Foreign) Reviewer for Research Grant Proposals
2009                       Member, STScI Working Group to write White Paper to describe "Cross-Mission Data Reduction and Analysis Planning:
                               The Evolution of IRAF, STSDAS, PyRAF and associated software"
2007 - 2011            Chair, Science Computing Working Group (STScI)
2006                       Member, LOC & SOC, STScI Workshop Galaxy Mergers: From the Local Universe to the Red Sequence
2005 - 2006            Member, STScI Science Advisory Resource Committee to write White Paper to describe "Unique Science with STIS
                               after HST Servicing Mission #4"
2005                       Chair, LOC & SOC, STScI Workshop The 2005 HST Calibration Workshop
2004 - 2007            Member, Science Computing Working Group (STScI)
2004                       Consultant, HST Failure Review Board on "Loss of STIS 5-V Power Supply and Subsequent Suspend" (NASA/GSFC)
2004                       Member, HST Anomaly Review Board on "No Lamp Flux in STIS ACQ Image Taken with HITM1 PtCrNe Lamp" (NASA/GSFC)
2003                       Member, STScI Science Advisory Resource Committee to review Draft HST Archive Enhancement Proposal
2003                       Member, LOC & SOC, STScI May Symposium "The Local Group as an Astrophysical Laboratory"
2003                       Member, STScI Staff Science Evaluation Committee
2001                       Member, HST Failure Review Board on "STIS Side-1 Failure" (NASA/GSFC)
2000                       Panel Member, Chandra TAC
1999 - 2000            Member, Charge Transfer Efficiency Working Group (STScI)
1998                       Member, LOC & SOC, STScI Workshop "The Formation of Galactic Bulges"
Since 1994             Member, American Astronomical Society
Since 1994             Referee for The Astrophysical Journal, The Astronomical Journal,
                               Monthly Notices of the Royal Astronomical Society, and Astronomy & Astrophysics