231 citations · 1.9k across the 41 of their papers we have counts for
19 papers · 1 filter
VV Pup in a low state: secondary-star irradiation or stellar activity?
Elena Mason, Steve B. Howell, Travis Barman +2
Aims. Emission lines in polars show complex profiles with multiple components that are typically ascribed to the accretion stream, threading region, accretion spot, and the irradia…
Origin and evolution of magnetars
Lilia Ferrario, D. T. Wickramasinghe
We present a population synthesis study of the observed properties of the magnetars, which allows for X-ray selection effects, investigating the hypothesis that they are drawn from…
Binary Star Origin of High Field Magnetic White Dwarfs
C. A. Tout, D. T. Wickramasinghe, J. Liebert +2
White dwarfs with surface magnetic fields in excess of MG are found as isolated single stars and relatively more often in magnetic cataclysmic variables. Some 1,253 white dwarf…
The birth properties of Galactic millisecond radio pulsars
Lilia Ferrario, Dayal Wickramasinghe
We model the population characteristics of the sample of millisecond pulsars within a distance of 1.5kpc.We find that for a braking index n=3, the birth magnetic field distribution…
High resolution spectra of bright central stars of bipolar planetary nebulae, and the question of magnetic shaping
T. -H. Lee, L. Stanghellini, L. Ferrario +1
We present ESO NTT high resolution echelle spectroscopy of the central stars (CSs) of eight southern bipolar planetary nebulae (PNe) selected for their asymmetry. Our aim was to de…
Spectropolarimetric Survey of Hydrogen-rich White Dwarf Stars
A. Kawka, S. Vennes, G. D. Schmidt +2
We have conducted a survey of 61 southern white dwarfs searching for magnetic fields using Zeeman spectropolarimetry. Our objective is to obtain a magnetic field distribution for t…
Modelling of isolated radio pulsars and magnetars on the fossil field hypothesis
Lilia Ferrario, Dayal Wickramasinghe
We explore the hypothesis that the magnetic fields of neutron stars are of fossil origin. For parametrised models of the distribution of magnetic flux on the Main Sequence and of t…
Time dependent non-LTE calculations of ionisation in the early universe
R. Wehrse, D. T. Wickramasinghe, Romeel Davé
We present a new implicit numerical algorithm for the calculation of the time dependent non-Local Thermodynamic Equilibrium of a gas in an external radiation field that is accurate…
The open cluster initial-final mass relationship and the high-mass tail of the white dwarf distribution
L. Ferrario, D. Wickramasinghe, J. Liebert +1
Recent studies of white dwarfs in open clusters have provided new constraints on the initial - final mass relationship (IFMR) for main sequence stars with masses in the range 2.5 -…
Could Edge-Lit Type Ia Supernovae be Standard Candles
Eniko Regos, Christopher A. Tout, Dayal Wickramasinghe +2
The progenitors of Type Ia supernovae (SNe Ia) have not been identified. Though they are no longer fashionable we investigate the consequences if a significant number of SNe Ia wer…
Studies of Magnetic and Suspected-Magnetic Southern White Dwarfs
G. D. Schmidt, S. Vennes, D. T. Wickramasinghe +1
Optical spectrophotometry and circular spectropolarimetry are presented for several candidate magnetic white dwarfs that were identified during the Hamburg/ESO survey for bright QS…
The Cyclotron Fundamental Exposed in the High-Field Magnetic Variable V884 Her
G. D. Schmidt, L. Ferrario, D. T. Wickramasinghe +1
High-quality phase-resolved optical spectropolarimetry is presented for the magnetic cataclysmic variable V884 Her. The overall circular polarization during active accretion states…
Type Ia Supernovae and Remnant Neutron Stars
A. R. King, J. E. Pringle, D. T. Wickramasinghe
On the basis of the current observational evidence, we put forward the case that the merger of two CO white dwarfs produces both a Type Ia supernova explosion and a stellar remnant…
WD1953-011 - a magnetic white dwarf with peculiar field structure
P. F. L. Maxted, L. Ferrario, T. R. Marsh +1
We present H-alpha spectra of the magnetic white dwarf star WD1953-011 which confirm the presence of the broad Zeeman components corresponding to a field strength of about 500kG fo…
Eccentric discs in binaries with intermediate mass ratios: Superhumps in the VY Sculptoris stars
J. R. Murray, B. Warner, D. T. Wickramasinghe
We investigate the role of the eccentric disc resonance in systems with mass ratios q greater than 1/4, and demonstrate the effects that changes in the mass flux from the secondary…
Thermal Instability and Evaporation of Accretion Disc Atmospheres
Martijn de Kool, Dayal T. Wickramasinghe
We investigate the thermal stability of the outer layers of accretion discs in which the local viscous energy dissipation rate scales with the pressure as for standard Shakura-Suny…
The effects of tidally induced disc structure on white dwarf accretion in intermediate polars
J. R. Murray, P. J. Armitage, L. Ferrario +1
We investigate the effects of tidally induced asymmetric disc structure on accretion onto the white dwarf in intermediate polars. Using numerical simulation, we show that it is pos…
Measuring the Motion of the Black Hole in GRO J16550-40
Roberto Soria, Dayal T. Wickramasinghe, Richard W. Hunstead +1
We report optical spectroscopic observations of the Low Mass X-ray Binary GRO J1655-40 during outbursts in August-September 1994 and in June 1996. The spectra show emission and abs…
Understanding the Cool DA White Dwarf, G29-38
S. J. Kleinman, R. E. Nather, D. E. Winget +37
The white dwarfs are promising laboratories for the study of cosmochronology and stellar evolution. Through observations of the pulsating white dwarfs, we can measure their interna…