相关论文: The Scale of Reddening for Classical Cepheid Varia…
We pose the question of how much information on the atmospheric parameters of late-type stars can be retrieved purely from colors using standard photometric systems. We carried out numerical experiments using stellar fluxes from model…
Motivated by an amazing range of reported distances to the nearby Local Group spiral galaxy M33, we have obtained deep near-infrared photometry for 26 long-period Cepheids in this galaxy with the ESO VLT. From the data we constructed…
We report on the discovery of Cepheids in the spiral galaxy NGC 2841, based on observations made with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope. NGC 2841 was observed over 12 epochs using the F555W filter,…
The light curves of Cepheids and other variable stars in Field A of IC 1613, obtained with a CCD and no filter ($Wh$ photometry), have been analyzed. It is possible to separate first overtone from fundamental mode population I Cepheids…
Over the past decade, the Secret Lives of Cepheids (SLiC) program has been carried out at Villanova University to study aspects and behaviors of classical Cepheids that are still not well-understood. In this, the first of several planned…
We investigate reddening by Milky Way dust in the low-extinction regime of $E_{B-V}<0.15$. Using over 50,000 QSOs at $0.5<z<2.5$ from the SDSS DR7 QSO Catalogue we probe the residual SDSS colours after dereddening and correcting for the…
We undertake a new test of the metallicity sensitivity of the Leavitt Law for Classical Cepheids. We derive an empirical calibration of the apparent luminosities of Cepheids as measured from the optical through the mid-infrared (0.45-8.0um)…
The Period-Luminosity (PL) relation is usually derived using time-averaged magnitudes, which require multiple-epoch observations to determine periods and adequately sample the light curves. Although single-epoch observations are more…
We utilize nonlinear pulsation models to reproduce the observed light and color curves for two samples of bump Cepheid variables, 19 from the Large Magellanic Cloud and 9 from the Small Magellanic Cloud. This analysis determines the…
Recent progress on Baade-Wesselink (BW)-type techniques to determine the distances to classical Cepheids is reviewed. Particular emphasis is placed on the near-infrared surface-brightness (IRSB) version of the BW method. Its most recent…
We have selected a sample of Galactic Cepheids for which accurate estimates of radii, distances, and photometric parameters are available. The comparison between their pulsation masses, based on new Period-Mass-Radius (PMR) relations, and…
We present a theoretical calibration of the RR Lyrae period-luminosity-color and period-color-color relations in the multiband uvby Stroemgren photometric system. Our theoretical work is based on calculations of synthetic horizontal…
We present measurements of reddening due to dust using the colors of stars in the Sloan Digital Sky Survey (SDSS). We measure the color of main sequence turn-off stars by finding the "blue tip" of the stellar locus: the prominent blue edge…
Using the "standard pair" technique of paring stars of almost nil and high extinction but otherwise of almost identical stellar parameters from the SDSS, and combing the SDSS, GALEX, 2MASS and WISE photometry ranging from the far UV to the…
We investigate the influence of blending on the Cepheid distance scale. Blending is the close association of a Cepheid with one or more intrinsically luminous stars. High-resolution HST images are compared to our ground-based data, obtained…
We have obtained deep images in the near-infrared J and K filters for several fields in the Local Group galaxy WLM. We report intensity mean magnitudes for 31 Cepheids located in these fields which we previously discovered in a wide-field…
We analyse a sample of 236 Cepheids from the Hipparcos catalog, using the method of ``reduced parallaxes'' in V, I, K and the reddening-free ``Wesenheit-index''. We compare our sample to those considered by Feast & Catchpole (1997) and…
Bayesian nonparametric regression with dependent wavelets has dual shrinkage properties: there is shrinkage through a dependent prior put on functional differences, and shrinkage through the setting of most of the wavelet coefficients to…
Using the M31 PAndromeda Cepheid sample and the HST PHAT data we obtain the largest Cepheid sample in M31 with HST data in four bands. For our analysis we consider three samples: A very homogeneous sample of Cepheids based on the PAndromeda…
Recent photometric observations of first-overtone classical Cepheids and RR Lyrae stars have led to the discovery of additional frequencies showing a characteristic period ratio of 0.60-0.65 with the main pulsation mode. In a promising…