17 citations · 53 across the 4 of their papers we have counts for
4 papers
Frequencies, chaos and resonances: a study of orbital parameters of nearby thick disc and halo stars
Helmer H. Koppelman, Jorrit H. J. Hagen, Amina Helmi
We study the distribution of nearby thick disc and halo stars in subspaces defined by their characteristic orbital parameters. Our aim is to establish the origin of the structure r…
Axisymmetric Schwarzschild models of an isothermal axisymmetric mock dwarf spheroidal galaxy
Jorrit H. J. Hagen, Amina Helmi, Maarten A. Breddels
We test the ability of Schwarzschild's orbit superposition method in measuring the mass content, scale radius and shape of a flattened dwarf spheroidal galaxy. Until now, most dyna…
The tilt of the velocity ellipsoid in the Milky Way with Gaia DR2
Jorrit H. J. Hagen, Amina Helmi, P. Tim de Zeeuw +1
The velocity distribution of stars is a sensitive probe of the gravitational potential of the Galaxy, and hence of its dark matter distribution. In particular, the shape of the dar…
The vertical force in the Solar Neighbourhood using red clump stars in TGASxRAVE - Constraints on the local dark matter density
Jorrit H. J. Hagen, Amina Helmi
We investigate the kinematics of red clump stars in the Solar Neighbourhood by combining data from TGAS and RAVE to constrain the local dark matter density. After calibrating the a…