Related papers: The Optical Gravitational Lensing Experiment. Shor…

We present UBV photometry of the eclipsing binary Harvard Variable 2274 in the Large Magellanic Cloud (LMC). The stellar parameters of this binary system were calculated by Guinan et al. (1998a) who gave both a reddening towards HV 2274 of…

We reanalyse the UV/optical spectrum and optical broad-band data of the eclipsing binary HV 2274 in the LMC, and derive its distance following the method given by Guinan et al. (1998a,b) of fitting theoretical spectra to the stars'…

We present a new method to determine the distance to B-stars in eclipsing binary systems. The method is completely empirical, and it is based on the existence of a very tight linear relationship between the V-band ``zero magnitude angular…

The distance to the Large Magellanic Cloud (LMC) is crucial for the calibration of the Cosmic Distance Scale. We derive a distance to the LMC based on an analysis of ground-based photometry and HST-based spectroscopy and spectrophotometry…

We analyze the mean luminosity of three samples of field RRab Lyr stars observed in the course of the OGLE microlensing experiment: 73 stars from the Galactic bulge and 110 and 128 stars from selected fields in the LMC and SMC,…

By employing two different spectroscopic techniques we have mapped out the variable ISM dust extinction endemic to globular cluster M4. We derive an average E(B-V) reddening of 0.33 +/- 0.01 and R = 3.4 +/- 0.4, both in good agreement with…

Photometry of the Galactic bulge, collected during the OGLE-II microlensing search, indicates high and non-uniform interstellar extinction toward the observed fields. We use the mean I-band magnitude and V-I color of red clump stars as a…

(abridged) New photometry and spectroscopy for more than a hundred RR Lyrae stars in two fields located close to the bar of the Large Magellanic Cloud (LMC) are used to derive new accurate estimates of the average magnitude, the local…

We have determined the distance to a second eclipsing binary system (EB) in the Large Magellanic Cloud, HV982 (~B1 IV-V + ~B1 IV-V). The measurement of the distance -- among other properties of the system -- is based on optical photometry…

We present a detailed map of the reddening in a 1.9 x 1.5 degree section of the Large Magellanic Cloud, constructed from UBVI photometry of 2069 O and B main sequence stars. We use two reddening-free photometric parameters to determine the…

We are carrying out an international, multi-wavelength program to determine the fundamental properties and independent distance estimates of selected eclipsing binaries in the LMC and SMC. Eclipsing binaries with well-defined double-line…

I demonstrate that the two unexpected results in the local Universe: anomalous intrinsic (V-I)_0 colors of RR Lyrae stars and clump giants in the Galactic center, and very short distances to Magellanic Clouds inferred from clump giants, can…

The Hipparcos I-band calibration of horizontal-branch red clump giants as standard candles has lead to controversial results for the distance to the Large Magellanic Cloud (LMC). In an attempt to properly ascertain the corrections for…

We derive the basic properties of seven Galactic open clusters containing Cepheids and construct their period-luminosity (P-L) relations. For our cluster main-sequence fitting we extend previous Hyades-based empirical color-temperature…

We use theoretical models to establish a tight relationship for the absolute magnitudes of RR Lyrae stars as a function of their periods and Stroemgren pseudo-color c_0 = (u-v)_0 - (v-b)_0. Applying this to RR Lyr, and comparing the result…

The zero point of the reddening toward the Large Magellanic Cloud (LMC) has been the subject of some dispute. Its uncertainty propagates as a systematic error for methods which measure the extragalactic distance scale through knowledge of…

We present reddening maps of the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC), based on color measurements of the red clump. Reddening values of our maps were obtained by calculating the difference of the observed and…

We present a new distance determination to the Large and Small Magellanic Clouds using the newly developed red clump stars method (Paczynski and Stanek 1998). This new, single-step, Hipparcos calibrated method seems to be one of the most…

Interstellar and atmospheric extinctions redden the observational photometric data and they should be handled rigorously. This paper simulates the effect of reddening for the modest case of two main sequence T1 = 6500K and T2 = 5500K…

We combine VI photometry from OGLE-III with VVV and 2MASS measurements of E(J-K_{s}) to resolve the longstanding problem of the non-standard optical extinction toward the Galactic bulge. We show that the extinction is well-fit by the…