1. Clustered star formation as a natural explanation for the Halpha cut-off in disk galaxies.

    Nature 455(7213):641 (2008) PMID 18833274

    The rate of star formation in a galaxy is often determined by the observation of emission in the Halpha line, which is related to the presence of short-lived massive stars. Disk galaxies show a strong cut-off in Halpha radiation at a certain galactocentric distance, which has led to the conclusi...
  2. Clustered star formation as a natural explanation for the Halpha cut-off in disk galaxies.

    Nature 455(7213):641 (2008) PMID 18833274

    The rate of star formation in a galaxy is often determined by the observation of emission in the Halpha line, which is related to the presence of short-lived massive stars. Disk galaxies show a strong cut-off in Halpha radiation at a certain galactocentric distance, which has led to the conclusi...
  3. The MODEST questions: Challenges and future directions in stellar cluster research

    New Astronomy 12(3):201 (2006)

    We present a review of some of the current major challenges in stellar cluster research, including young clusters, globular clusters, and galactic nuclei. Topics considered include: primordial mass segregation and runaway mergers, expulsion of gas from clusters, the production of stellar ex...
  4. The MODEST questions: Challenges and future directions in stellar cluster research

    New Astronomy 12(3):201 (2006)

    We present a review of some of the current major challenges in stellar cluster research, including young clusters, globular clusters, and galactic nuclei. Topics considered include: primordial mass segregation and runaway mergers, expulsion of gas from clusters, the production of stellar ex...
  5. Astronomy: stellar mass limited.

    Nature 434(7030):148 (2005) PMID 15758978

  6. Astronomy: stellar mass limited.

    Nature 434(7030):148 (2005) PMID 15758978

  7. Massive stars: their birth sites and distribution

    New Astronomy Reviews 48(1):47 (2004)

    The stellar IMF has been found to be an invariant Salpeter power-law ( α=2.35) above about 1 M ⊙, but at the same time a massive star typically has more than one companion. This constrains the possible formation scenarios of massive stars, but also implies that the true, ...
  8. MODEST-2: a summary

    New Astronomy 8(6):605 (2003)

    This is a summary paper of MODEST-2, a workshop held at the Astronomical Institute ‘Anton Pannekoek’ in Amsterdam, 16–17 December 2002. MODEST is a loose collaboration of people interested in MOdelling DEnse STellar systems, particularly those interested in modelling these systems using all...
  9. MODEST-2: a summary

    New Astronomy 8(6):605 (2003)

    This is a summary paper of MODEST-2, a workshop held at the Astronomical Institute ‘Anton Pannekoek’ in Amsterdam, 16–17 December 2002. MODEST is a loose collaboration of people interested in MOdelling DEnse STellar systems, particularly those interested in modelling these systems using all...
  10. The initial mass function of stars: evidence for uniformity in variable systems.

    Science 295(5552):82 (2002) PMID 11778039

    The distribution of stellar masses that form in one star formation event in a given volume of space is called the initial mass function (IMF). The IMF has been estimated from low-mass brown dwarfs to very massive stars. Combining IMF estimates for different populations in which the stars can be ...
  11. The initial mass function of stars: evidence for uniformity in variable systems.

    Science 295(5552):82 (2002) PMID 11778039

    The distribution of stellar masses that form in one star formation event in a given volume of space is called the initial mass function (IMF). The IMF has been estimated from low-mass brown dwarfs to very massive stars. Combining IMF estimates for different populations in which the stars can be ...
  12. EfficientN-body realisations of axisymmetric galaxies and halos

    New Astronomy 6(1):27 (2001)

    We present an efficient method for building equilibrium multi-component galaxies with non-spherical haloes and bulges. The gist of our approach is to tailor the velocity ellipsoid directly to the geometry of the mass distribution. Thus we avoid computing the anisotropic velocity dispersions...
  13. Constraints on stellar-dynamical models of the Orion Nebula Cluster

    New Astronomy 4(8):615 (2000)

    The results obtained by Kroupa, Petr & McCaughrean (1999) for specific models of young compact binary-rich clusters are generalised using dynamical scaling relations, to infer the candidate set of possible birth models leading to the Orion Nebula Cluster (ONC), of which the Trapezium Cluste...
  14. Binary stars in young clusters: models versus observations of the Trapezium Cluster

    New Astronomy 4(7):495 (1999)

    The frequency of low-mass pre-main sequence binary systems is significantly lower in the Trapezium Cluster than in Taurus-Auriga. We investigate if this difference can be explained through stellar encounters in dense clusters. To this effect, a range of possible models of the well observed ...
  15. Binary stars in young clusters: models versus observations of the Trapezium Cluster

    New Astronomy 4(7):495 (1999)

    The frequency of low-mass pre-main sequence binary systems is significantly lower in the Trapezium Cluster than in Taurus-Auriga. We investigate if this difference can be explained through stellar encounters in dense clusters. To this effect, a range of possible models of the well observed ...
  16. The Hipparcos proper motion of the Magellanic Clouds

    New Astronomy 2(1):77 (1997)

    The proper motion of the Large (LMC) and Small (SMC) Magellanic Cloud using data acquired with the Hipparcos satellite is presented. Hipparcos measured 36 stars in the LMC and 11 stars in the SMC. A correctly weighted mean of the data yields the presently available most accurate values, ...
  17. The Hipparcos proper motion of the Magellanic Clouds

    New Astronomy 2(1):77 (1997)

    The proper motion of the Large (LMC) and Small (SMC) Magellanic Cloud using data acquired with the Hipparcos satellite is presented. Hipparcos measured 36 stars in the LMC and 11 stars in the SMC. A correctly weighted mean of the data yields the presently available most accurate values, ...
  18. Dwarf spheroidal satellite galaxies without dark matter

    New Astronomy 2(2):139 (1997)

    Self-consistent simulations of the interaction of initially spherical low-mass satellite galaxies with a massive Galactic dark halo suggest that observed apparent high mass-to-light ratios, ( M L ) obs , in dwarf-spheroidal...
  19. Dwarf spheroidal satellite galaxies without dark matter

    New Astronomy 2(2):139 (1997)

    Self-consistent simulations of the interaction of initially spherical low-mass satellite galaxies with a massive Galactic dark halo suggest that observed apparent high mass-to-light ratios, ( M L ) obs , in dwarf-spheroidal...