Related papers: On the Oosterhoff dichotomy in the Galactic bulge:…

We made a survey of the variable stars in a $13.2 \times 13.2$ arcmin$^2$ centered on the field of the Galactic bulge cluster NGC 6558. A total of 78 variables was found in the field of the cluster. Many of these variables are included in…

A sample of 45 symbiotic stars observed in the direction of the galactic bulge are classified in spectral type using TiO $\lambda \lambda 6180, 7100 \AA$ and VO $\lambda \lambda 7865 \AA$ absorption feature indices and visual comparison.…

We present the results of a search for pulsating stars in the 7.12 deg^2 OGLE-III Galactic disk area in the direction tangent to the Centaurus Arm. We report the identification of 20 Classical Cepheids, 45 RR Lyr type stars, 31 Long-Period…

We propose a new method to investigate the coefficient of the selective extinction, based on two band photometry. This method uses red clump stars as a means to construct the reddening curve. We apply this method to the OGLE color-magnitude…

The color-magnitude diagram of $ \sim 3 \times 10^5 $ stars obtained for Baade's Window towards the Galactic bulge with the OGLE project reveals a surprisingly narrow main sequence due to galactic disk stars at a distance of $d \sim 2 $…

The VISTA Variables in the V\'ia L\'actea (VVV) is a near-IR time-domain survey of the Galactic bulge and southern plane. One of the main goals of this survey is to reveal the 3D structure of the Milky Way through their variable stars.…

We have used photometric data on almost 91 000 fundamental-mode RR Lyrae stars (type RRab) detected by the OGLE survey to investigate properties of old populations in the Milky Way. Based on their metallicity distributions, we demonstrate…

We present new BV CCD photometry, light curves, and ephemerides for 9 previously known, 29 newly detected RR Lyrae variables and one newly detected variable of an unknown type in the globular cluster M75. The photometry used for the…

We present the fifth part of the OGLE Catalog of Periodic Variable Stars in the Galactic bulge. 574 variable stars: 44 pulsating, 369 eclipsing and 161 miscellaneous type were detected in four fields located symmetrically in galactic…

The third part of the OGLE-III Catalog of Variable Stars comprises 24906 RR Lyr stars in the Large Magellanic Cloud (LMC). This sample consists of 17693 fundamental-mode (RRab), 4958 first-overtone (RRc), 986 double-mode (RRd) and 1269…

Understanding the structure, formation and evolution of the Galactic Bulge requires the proper determination of spatial metallicity gradients in both the radial and vertical directions. RR Lyrae pulsators, known to be excellent distance…

The color-magnitude diagrams of $\sim 1 \times 10^6$ stars obtained for 19 fields towards the Galactic bulge with the OGLE project reveal a well-defined population of bulge red clump stars. We found that the distributions of the…

We present a $\approx 11.5$ year adaptive optics (AO) study of stellar variability and search for eclipsing binaries in the central $\sim 0.4$ pc ($\sim 10''$) of the Milky Way nuclear star cluster. We measure the photometry of 563 stars…

The Optical Gravitational Lensing Experiment (OGLE) is a great source of top-quality photometry of classical pulsators. Collection of variable stars from the fourth part of the project contains more than 38 000 RR Lyrae stars. These stars…

We present our analysis of a large sample (over 150k) of candidate Galactic RR Lyrae (RRL) stars for which we derived high quality photometry at UV, optical and infrared wavelengths, using data from publicly available surveys. For a…

I present an implementation of the difference image photometry based on the Alard & Lupton optimal PSF matching algorithm. The most important feature distinguishing this method from the ones using Fourier divisions is that equations are…

The first calibrated broadband BVI time-series photometry is presented for the variable stars in NGC 2808, with observations spanning a range of twenty-eight years. We have also redetermined the variability types and periods for the…

We developed a parametric Galactic model toward the Galactic bulge by fitting to spatial distributions of the Gaia DR2 disk velocity, VVV proper motion, BRAVA radial velocity, OGLE-III red clump star count, and OGLE-IV star count and…

Intensive monitoring of low-extinction windows towards the galactic bulge has provided in the last years valuable information for studies about the dynamics, kinematics and formation history of this part of the galaxy, mainly by…

(abridged) The 222000 I-band light curves of variable stars detected by the OGLE-II survey in the direction of the Galactic Bulge have been fitted and have also been correlated with the DENIS and 2MASS databases. Results are presented for…