La Douleur et Son Traitement

Antonello, Marc; Delplanque, Dominique

doi:10.1016/b978-2-294-70799-5.50050-2

Cited by 4 publications

(3 citation statements)

References 1 publication

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“…This is a demonstration of the well-known strong resonance between the fundamental mode and second overtone for 10 ≤ P 13 days (e.g. Simon & Lee 1981;Antonello & Morelli 1996). This resonance is responsible for most of the structure seen in the residuals in Figure 3, and for the "jump" in the upper envelope of amplitudes at ∼ 13 days in Figure 15.…”

Section: Metallicity Effects In the Fit Residualssupporting

confidence: 52%

A Global Physical Model for Cepheids

Pejcha

Kochanek

2012

ApJ

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We perform a global fit to ∼5, 000 radial velocity and ∼177, 000 magnitude measurements in 29 photometric bands covering 0.3 µm to 8.0 µm distributed among 287 Galactic, LMC, and SMC Cepheids with P > 10 days. We assume that the Cepheid light curves and radial velocities are fully characterized by distance, reddening, and time-dependent radius and temperature variations. We construct phase curves of radius and temperature for periods between 10 and 100 days, which yield light curve templates for all our photometric bands and can be easily generalized to any additional band. With only 4 to 6 parameters per Cepheid, depending on the existence of velocity data and the amount of freedom in the distance, the models have typical rms light and velocity curve residuals of 0.05 mag and 3.5 km s −1 . The model derives the mean Cepheid spectral energy distribution and its derivative with respect to temperature, which deviate from a black body in agreement with metal-line and molecular opacity effects. We determine a mean reddening law towards the Cepheids in our sample, which is not consistent with standard assumptions in either the optical or near-IR. Based on stellar atmosphere models we predict the biases in distance, reddening, and temperature determinations due to the metallicity and we quantify the metallicity signature expected for our fit residuals. The observed residuals as a function of wavelength show clear differences between the individual galaxies, which are compatible with these predictions. In particular, we find that metal-poor Cepheids appear hotter. Finally, we provide a framework for optimally selecting filters that yield the smallest overall errors in Cepheid parameter determination, or filter combinations for suppressing or enhancing the metallicity effects on distance determinations. We make our templates publicly available.

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Section: Metallicity Effects In the Fit Residualssupporting

confidence: 52%

A Global Physical Model for Cepheids

Pejcha

Kochanek

2012

ApJ

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“…The P 3 : P 0 = 1 : 3 resonance (Moskalik & Buchler 1989;Antonello & Morelli 1996) has no visible effect, neither on the computed phase lag nor on the A 1 (V ) diagrams. Moskalik & Buchler (1990) showed that another possible resonance, P 1 : P 0 = 2 : 3 (Antonello & Morelli 1996) has no effect unless it destabilizes the F limit cycle, in which case it causes the appearance of slightly alternating pulsation cycles (period doubling).…”

Section: Pulsation Amplitudesmentioning

confidence: 85%

The Cepheid Phase Lag Revisited

Szabo

Buchler

Bartee

2007

ApJ

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We compute the phase lags between the radial velocity curves and the light curves $\Delta \Phi_1= \phi^{V_r}_1 - \phi^{mag}_1$ for classical Cepheid model sequences both in the linear and the nonlinear regimes. The nonlinear phase lags generally fall below the linear ones except for high period models where they lie above, and of course for low pulsation amplitudes where the two merge. The calculated phase lags show good agreement with the available observational data of normal amplitude Galactic Cepheids. The metallicity has but a moderate effect on the phase lag, while the mass-luminosity relation and the parameters of the turbulent convective model (time-dependent mixing length) mainly influence the modal selection and the period, which is then reflected in the period -- $\Delta \Phi_1$ diagram. We discuss the potential application of this observable as a discriminant for pulsation modes and as a test for ultra-low amplitudes (ULA) pulsation.Comment: 11 pages, 8 figures, accepted for publication in ApJ, minor revisions in the text and figures, (black and white version available from 2nd author's website

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“…Finally, as a check, the MW V-band data were compared to an earlier compilation by Antonello & Morelli (1996) of data for Galactic Cepheids with periods longer than 8 d. In order that the two data sets be compatible, the same restriction was imposed on the data. Significance levels for all statistics except SKS (p = 0.83) and NNDD (p = 0.67) were larger than 0.90.…”

Section: A P P L I C At I O N To T H E F O U R I E R C O E F F I C I mentioning

confidence: 99%

Multivariate comparisons of the period-light-curve shape distributions of Cepheids in five galaxies

Koen¹,

Siluyele²

2007

Monthly Notices of the Royal Astronomical Society

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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. It is found that a statistic due to Henze has good general performance. The tests are applied to Cepheid observations in the Milky Way galaxy, Large Magellanic Cloud, Small Magellanic Cloud, IC 1613 and NGC 6822. The null hypothesis of equal populations is rejected for all pairs compared, except IC 1613 – NGC 6822.

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La Douleur et Son Traitement

Cited by 4 publications

References 1 publication

A Global Physical Model for Cepheids

A Global Physical Model for Cepheids

The Cepheid Phase Lag Revisited

Multivariate comparisons of the period-light-curve shape distributions of Cepheids in five galaxies

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