Search Publications
Structure and colour-magnitude diagrams of Scorpius OB2 based on kinematic modelling of Hipparcos data
de Bruijne, Jos H. J.
All stars in a `moving group' share the same space motion. The presence of such a coherent structure in velocity space can be used to derive (improved) estimates of the stellar parallaxes from the observed positions and proper motions. A Lund Observatory group (Dravins et al.) describes an elegant and sophisticated maximum likelihood procedure to …
A deep VLA survey at 20 CM of the ISO ELAIS survey regions
Genzel, R.; Cesarsky, C.; Danese, L. +11 more
We have used the Very Large Array (VLA) in C configuration to carry out a sensitive 20-cm radio survey of regions of sky that have been surveyed in the far-infrared (FIR) over the wavelength range 5--200 µm with ISO (Infrared Space Observatory) as part of the European Large-Area ISO Survey (ELAIS). As usual in surveys based on a relatively s…
The evolution of cluster E and S0 galaxies measured from the Fundamental Plane
van Dokkum, Pieter G.; Franx, Marijn; Hjorth, Jens +1 more
Photometry has been obtained for magnitude-limited samples of galaxies in the rich clusters Abell 665 (37 galaxies) and Abell 2218 (61 galaxies). Both clusters have a redshift of 0.18. The limiting magnitude of the samples is 19mag in the I band. Spectroscopy has been obtained for seven galaxies in A665 and nine galaxies in A2218, all of which als…
The detection of dust in the central galaxies of distant cooling-flow clusters
Kneib, J. -P.; Ivison, R. J.; Smail, Ian +2 more
We present 850-µ observations with the SCUBA submillimetre (sub-mm) camera of the central galaxies in seven concentrated clusters of galaxies at redshifts between 0.19 and 0.41. We detect sub-mm emission from the central galaxies in the rich clusters A1835 and A2390, and present upper limits for the central galaxies in the remaining five clu…
Deriving star formation histories: inverting Hertzsprung-Russell diagrams through a variational calculus maximum likelihood method
Gilmore, Gerard; Valls-Gabaud, David; Hernandez, X.
We introduce a new method for solving maximum likelihood problems through variational calculus, and apply it to the case of recovering an unknown star formation history, SFR(t), from the resulting Hertzsprung-Russell (HR) diagram. This approach allows a totally non-parametric solution, which has the advantage of requiring no initial assumptions ab…
A refurbished convergent-point method for finding moving groups in the HIPPARCOS Catalogue
de Bruijne, Jos H. J.
The Hipparcos data allow a major step forward in the research of `moving groups' in the Solar neighbourhood, as the common motion of group members causes converging proper motions. Previous knowledge of these coherent structures in velocity space has always been limited by the availability, reliability and accuracy of ground-based proper-motion me…
A Bayesian classifier for photometric redshifts: identification of high-redshift clusters
Bell, Eric F.; Kodama, Tadayuki; Bower, Richard G.
Photometric redshift classifiers provide a means of estimating galaxy redshifts from observations using a small number of broad-band filters. However, the accuracy with which redshifts can be determined is sensitive to the star formation history of the galaxy, for example the effects of age, metallicity and ongoing star formation. We present a pho…
Homogeneous photometry and metal abundances for a large sample of Hipparcos metal-poor stars*
Clementini, G.; Sneden, C.; Carretta, E. +1 more
Homogeneous photometric data (Johnson V, B-V, V-K, Cousins V-I and Strömgren b-y), radial velocities, and abundances of Fe, O, Mg, Si, Ca, Ti, Cr and Ni are presented for 99 stars with high-precision parallaxes measured by the Hipparcos satellite. These data have been previously used to assist the derivation of accurate distances and ages of Galac…
The optical-infrared colour distribution of a statistically complete sample of faint field spheroidal galaxies
Menanteau, F.; Abraham, R. G.; Barger, A. J. +2 more
In hierarchical models, where spheroidal galaxies are primarily produced via a continuous merging of disc galaxies, the number of intrinsically red systems at faint limits will be substantially lower than in `traditional' models where the bulk of star formation was completed at high redshifts. In this paper we analyse the optical-near-infrared col…
The pattern speed of the bar in NGC 4596
Gerssen, Joris; Kuijken, Konrad; Merrifield, Michael R.
The pattern speed is a defining parameter of any barred galaxy. A large number of model-dependent techniques have therefore been developed to derive the pattern speed. However, the only model-independent technique for measuring this quantity - the Tremaine-Weinberg method - has hitherto been applied to just one case, the SB0 galaxy NGC 936. In thi…