Search Publications
Circumnuclear regions in barred spiral galaxies - I. Near-infrared imaging
Knapen, J. H.; Pérez-Ramírez, D.; Peletier, R. F. +3 more
We present subarcsecond-resolution, ground-based, near-infrared images of the central regions of a sample of 12 barred galaxies with circumnuclear star formation activity, which is organized in ring-like regions typically 1kpc in diameter. We also present Hubble Space Telescope near-infrared images of 10 of our sample galaxies, and compare them wi…
A strategy for finding gravitationally lensed distant supernovae
Ellis, Richard; Smail, Ian; Madau, Piero +2 more
Distant Type Ia and II supernovae (SNe) can serve as valuable probes of the history of the cosmic expansion and star formation, and provide important information on their progenitor models. At present, however, there are few observational constraints on the abundance of SNe at high redshifts. A major science driver for the Next Generation Space Te…
Deep spectroscopy of distant 3CR radio galaxies: the data
Röttgering, H. J. A.; Best, P. N.; Longair, M. S.
Deep long-slit spectroscopic data are presented for a sample of 14 3CR radio galaxies at redshift z~1, previously studied in detail using the Hubble Space Telescope, the Very Large Array, and the UK Infrared Telescope (UKIRT). Analysis of the [Oii] 3727 emission-line structures at ~5Å spectral resolution is carried out to derive the kinematic prop…
Two-dimensional modelling of optical Hubble Space Telescope and infrared tip-tilt images of quasar host galaxies
McLure, R. J.; Dunlop, J. S.; Kukula, M. J.
A description is given of the method used to extract quasar host-galaxy parameters from the deep Hubble Space Telescope (HST) quasar images presented by McLure, Dunlop and co-workers. We then give the results of extensive testing of this technique on a wide range of simulated quasar+host combinations spanning the redshift range of our HST study (0…
A moving group of young stars in Carina-Vela
Makarov, Valeri V.; Urban, Sean
Accurate two-colour photometry and proper motions of 7096 young X-ray stars in the ROSAT All-Sky Survey Bright Star Catalogue, version 1RXS, are extracted from the Tycho-2 Catalogue. The sample is dominated by red main-sequence and possibly pre-main-sequence stars. On a global proper motion convergence map, two features are very prominent: the nea…
Absolute magnitudes of OB and Be stars based on Hipparcos parallaxes
Wegner, W.
Absolute visual magnitudes of OB stars are determined from Hipparcos parallaxes using a sample of 1207 unreddened and 441 reddened stars of luminosity classes V-IV, III, Ia and Iab-Ib-II. The value of total-to-selective extinction R for reddened stars was calculated from near-infrared photometry. The new MV calibration is compared with …
The timing properties of Sco X-1 along its Z track with EXOSAT
van der Klis, Michiel; Dieters, Stefan W.
We present a systematic, homogeneous analysis of all the EXOSAT ME, high time resolution data on Sco X-1. We investigate, for the first time, all power spectral properties of the <100Hz quasi-periodic oscillations (QPO) and noise of Sco X-1 as a function of position on the Z-shaped track traced out in the X-ray colour-colour diagram. For this p…
NICMOS images of JVAS/CLASS gravitational lens systems
Jackson, N.; Browne, I. W. A.; Xanthopoulos, E.
We present Hubble Space Telescope (HST) infrared images of four gravitational lens systems from the JVAS/CLASS gravitational lens survey and compare the new infrared HST pictures with previously published WFPC2 HST optical images and radio maps. Apart from the wealth of information that we get from the flux ratios and accurate positions and separa…
The evolution of 3CR radio galaxies from z1
McLure, R. J.; Dunlop, J. S.
We present the results of a comprehensive re-analysis of the images of a virtually complete sample of 28 powerful 3CR radio galaxies with redshifts 0.6<z<1.8 from the Hubble Space Telescope (HST) archive. Using a two-dimensional modelling technique we have derived scalelengths and absolute magnitudes for a total of 16 3CR galaxies with a med…
Rapidly oscillating M giant stars?
Koen, Chris; Laney, Dave
The Hipparcos mission discovered a few dozen M giant stars with periods P shorter than 10d. Similar stars may be found in other large data bases of new variables (e.g., OGLE). The three possible sources of the magnitude variations - pulsation, starspots and ellipsoidal deformation - are discussed in general terms. The parallaxes and V-I colour ind…