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Evidence for rapid evolution of periodic variations in an ultracool dwarf
(Oxford University Press, 2006)
The results of three short photometric monitoring runs on the L0 dwarf 2MASS
J06050196−2342270, during three consecutive nights, are presented. The observations show
the persistent presence of a 2.4-h period, with an IC ...
Multiple regression of GRB luminosity on light-curve properties
(Oxford University Press, 2009)
Statistical relations between the luminosity L of gamma-ray burster (GRBs) and several of
their other observable properties have been discovered. Four of these properties are considered
here: the spectral lag; a measure ...
IC and RC band time-series observations of some bright ultracool dwarfs
(Oxford University Press, 2005)
The results of more than 100 h of CCD photometric monitoring of 10 L dwarfs and two T dwarfs
are presented. Reasonable evidence is shown for IC band variability in DENIS 0255−4700,
DENIS 1705−0516 and 2M 2104−1037. ...
Fitting power-law distributions to data with measurement errors
(Oxford University Press, 2009)
If X, which follows a power-law distribution, is observed subject to Gaussian measurement
error e, thenX+e is distributed as the convolution of the power-lawand Gaussian distributions.
Maximum-likelihood estimation of ...
Fitting sinusoids to observations of rotating spotted stars
(Oxford University Press, 2007)
It is assumed that K blocks (e.g. seasons) of observations are available, and the parameters
characterizing a fixed-frequency sinusoidal variability (mean light level, amplitude, phase)
are constant within each of the ...
Improved SAAO–2MASS photometry transformations
(Oxford University Press, 2007)
Near-infrared photometry of 599 stars is used to calculate transformations from the South
African Astronomical Observatory (SAAO) JHK system to the Two-Micron All-Sky Survey
(2MASS) JHKS system. Both several-term formal ...
HE0230–4323: an unusual pulsating hot subdwarf star
(Oxford University Press, 2007)
HE 0230−4323 is a known binary, consisting of a subdwarf star and a companion which is not
observable in the optical. Photometric measurements reported in this paper have shown it to be
both a reflection-effect and a ...
Statistical tests for changes in the amplitude, frequency or phase of a sinusoidal variation
(Oxford University Press, 2009)
The problem considered is that of testing for small changes over time in the properties of
a sinusoidal signal contaminated by noise. Two test statistics are proposed. The first is a
frequency domain statistic based on ...
Correcting CCD photometry of stars for seeing effects
(Oxford Univeristy Press, 2009)
Systematic variability in stellarmagnitudes, as derived from profile fitting to CCD images,may
in some instances be due to variable seeing. It is suggested that this happens in cases where the
stars are unresolved pairs, ...
Multivariate comparisons of the period–light-curve shape distributions of Cepheids in five galaxies
(Oxford University Press, 2007)
A number of published tests suitable for the comparison of multivariate distributions are
described. The results of a small power study, based on realistic Cepheid log period – Fourier
coefficient data, are presented. ...