Research team

Applied mathematics

Expertise

Data reduction for echelle spectra; Doppler-shift measurement by means of cross-correlation and alternative techniques.

Digital access to aero- andf astrophotographic archives. 15/12/2001 - 30/04/2004

Abstract

The aim of the project is to digitize the existing archives of aerial photographs and astronomical plates (in particular the "Carte du Ciel") in order to ensure the safe conservation of the data and to and to make them accessible to modern research. In the first phase a dedicated plate-measuring machine will be developed and tests will be done to verify that the resulting data will have the required quality.

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    A HIPPARCOS-based study of the binary population in the nearby OB associations. 01/12/2001 - 30/11/2005

    Abstract

    The project contributes to the establishment of a homogeneous data base on the physically relevant parameters characterising the binary systems in nearby OB associations, and to analyse the distribution of these parameters with a view to detect possible signatures of the star formation process.

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      The effect of spectral idiosyncracies on relative radial-velocity measurements. 01/11/1998 - 30/11/1999

      Abstract

      Radial velocities are measured by cross-correlating two similar spectra. If the spectra do not match closely enough in a number of important aspects, the spurious and misleading errors can arise. The research concerns such errors that are due to certain astrophysical factors.

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        A comparative study of quality criteria in non-parametric density estimation. 01/05/1998 - 30/04/2000

        Abstract

        In non-parametric density estimation one has a choice between different quality criteria to optimize the smoothness of the estimate. Using simulation several such criteria are compared regarding their effect on the characteristics of the resulting estimate, in order to improve one's ability to match the choice of the criterion to the specific aims of one's data-analysis.

        Researcher(s)

        • Promotor: David Marc
        • Co-promotor: Verschueren Werner

        Research team(s)

          The interpretation of kinematical data on stellar clusters. 01/01/1997 - 31/12/1997

          Abstract

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            A system for the determination of accurate radial velocities of early-type stars, with application to young stellar groups. 01/10/1996 - 30/09/1999

            Abstract

            The radial velocity of a star is determined from the position of the maximum of the cross- correlation function of its spectrum and a template spectrum for which the radial velocity is known. This technique is well established and successful for most stars, but in the case of early-type stars serious systematic errors may occur due to inevitable small structural differences between object- and template spectrum. This study aims to clarify the relation between spectral differences and the resulting false shift of the correlation peak, and to design refinements to the measurement procedure which minimize these errors.

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              A system for determining accurate radial velocities of early-type stars. 01/01/1996 - 31/12/1997

              Abstract

              The measurement of a Doppler shift between two spectra by means of cross-correlation may be biased due to small structural differences between the spectra; the importance of this bias is studied in order to establish conditions which the spectra should satisfy in order to permit measurements with a given accuracy.

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                Analysis of echelle spectra of early-type stars. 01/07/1995 - 31/12/1996

                Abstract

                High resolution CCD echelle spectra (wavelength region: 380nm to 410 nm) of early-type stars are analyzed differentially to control (and where necessary to correct) their mutual consistency; particular attention is paid to the estimated continuum level.

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                  Interpretation of kinematical data about open star clusters. 01/05/1995 - 30/04/1997

                  Abstract

                  The deduction of information about the dynamic condition of a star cluster from kinematical data (masses, positions, speeds) about the members of the cluster, is heavily curtailed by the impossibility to determine directly some of the magnitudes and by the inevitable incompleteness of the sampling. A solution is sought through improved models and recent statistical techniques.

                  Researcher(s)

                  • Promotor: David Marc
                  • Co-promotor: Verschueren Werner

                  Research team(s)

                    Belgian network for an optimized reduction of astrophysical data. 01/10/1992 - 31/03/1997

                    Abstract

                    The basic aims are to promulgate within the Belgian astronomical community the use of large telescopes and of their sophisticated instrumentation and associated modern detectors, and to facilitate the reduction and analysis of astrophysical data, thus acquired.

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                      01/10/1991 - 30/09/1992

                      Abstract

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                        01/01/1990 - 31/12/1994

                        Abstract

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                          Stellar dynamics : study of the dynamics of young stellar groups embedded in clouds of interstellar gas and dust. 01/01/1986 - 31/12/1996

                          Abstract

                          Using simplified analytical models and numerical experiments we study the behaviour of systems of self-gravitating mass points under the influence of a heavy inhomogeneous and time-dependent mass distribution.

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