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تسجيل مستخدم جديدNear-infrared observations of OGLE classical and type II Cepheid variables in the LMC
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We present results from the Large Magellanic Cloud Near-infrared Synoptic Survey (LMCNISS) for classical and type II Cepheid variables that were identified by the Optical Gravitational Lensing Experiment (OGLE-III) catalogue. Multiwavelength time-series data for classical Cepheid variables are used to study light-curve structures as a function of period and wavelength. We exploit a sample of $sim$1400 classical and $sim$80 type II Cepheid variables to derive Period--Wesenheit relations that combine both optical and near-infrared data. The new Period--Luminosity and Wesenheit relations are used to estimate distances to several Local Group galaxies (using classical Cepheids) and to Galactic globular clusters (using type II Cepheids). By appealing to a statistical framework, we find that fundamental-mode classical Cepheid Period--Luminosity relations are non-linear around 10--18 days at optical and near-IR wavelengths. We also suggest that a non-linear relation provides a better constraint on the Cepheid Period--Luminosity relation in type Ia Supernovae host galaxies, though it has a negligible effect on the systematic uncertainties affecting the local measurement of the Hubble constant.
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