Browsing Researchers in Statistics and Population Studies by Title
Now showing items 5-24 of 55
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Confidence intervals for the correlation between the gamma-ray burst peak energy and the associated supernova peak brightness
(Oxford University Press, 2009)A strong correlation between the gamma-ray burster peak energy and the peak luminosity of the associated supernova was discovered by Li for four GRBs. Despite the fact that the formal significance level of the correlation ... -
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, ... -
The detailed forms of the LMC Cepheid PL and PLC relations
(Oxford University Press, 2007)Possible deviations from linearity of the Large Magellanic Cloud Cepheid period–luminosity (PL) and period–luminosity–colour (PLC) relations are investigated. Two data sets are studied, respectively from the Optical ... -
Detection of an increasing orbital period in the subdwarf B eclipsing system NSVS 14256825
(Oxford University Press, 2012)New timings of eclipses made in 2010 and 2011 are presented for the hot subdwarf B (sdB) eclipsing binary NSVS 14256825. Composed of an sdB star and a much cooler companion, with a period near 0.1104 days, this system ... -
A detection threshold in the amplitude spectra calculated from Kepler data obtained during K2 mission.
(Oxford University Press, 2015)We present our analysis of simulated data in order to derive a detection threshold which can be used in the pre-whitening process of amplitude spectra. In case of ground-based data of pulsating stars, this threshold is ... -
Estimation of the coherence time of stochastic oscillations from modest samples
(Oxford University Press, 2012)‘Quasi-periodic’ or ‘solar-like’ oscillations can be described by three parameters – a characteristic frequency, a coherence time (or ‘quality factor’) and the variance of the random driving process. This paper is concerned ... -
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 ... -
An extensive search for rapid optical variability in ultracool dwarfs
(Oxford University Press, 2013)In this paper, a summary of optical time-series photometry of 125 ultracool dwarfs is given. The observing strategy was to monitor each object continuously for 2–3 h in order to ascertain whether itwas rapidly variable. ... -
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 ... -
The “four sigma” limit for significant periodicities
(Springer Verlag, 2010)Most of the pulsations which have been observed in sdB stars have very low amplitudes. Detection of modes from photometric observations is usually performed by noting the most prominent peaks in a periodogram or, ... -
Further observations of Hipparcos red stars and standards for UBV(RI)C photometry
(Oxford University Press, 2007)We present homogeneous and standardized UBV(RI)C JHK photometry for over 100 M stars selected from an earlier paper on the basis of apparent photometric constancy. L photometry has been obtained for stars brighter than ... -
HE 0230−4323 revisited: a new rapidly pulsating sdB star
(Oxford University Press, 2010)HE 0230−4323 is a hot sdB star in a binary system. An earlier work demonstrated that the light curve of the system shows a strong (∼4 per cent) reflection effect and also appears to exhibit photometric variations of the ... -
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 ... -
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. ... -
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 ... -
Is there evolution in the infrared Tully–Fisher relation? Comparing two linear regressions
(Oxford University Press, 2009)In a recent paper, Puech and co-workers compared K-band Tully–Fisher relations derived for nearby and distant galaxies, respectively. They concluded that the two relations differ, and deduced that there is evolution in ... -
JHKs time-series observations of a few ultracool dwarfs
(Oxford University Press, 2005)The M8.5 object SSSPM J0109−5101 has recently been shown to be both a periodic and a flaring variable, based on optical observations in the extreme red. More than 16 h of monitoring in the near-infrared (NIR) reported ... -
JL 82: a slowly pulsating hot subdwarf star in a close binary system
(Oxford University Press, 2009)JL 82 is a known binary, consisting of an sdB star and a companion which is not directly observable in the optical. Photometric measurements reported in this paper show it to variable with both the binary period (∼0.75 ... -
KPD 0629–0016, a slowly pulsating hot subdwarf star
(Oxford University Press, 2007)The results of nine CCD photometric observing runs on KPD 0629–0016 are presented. During six of the runs measurements were obtained alternately through B and V filters. Four periodicities, for which there is good agreement ...
