Related papers: Galactic and Extragalactic Distance Scales: The Va…
The DIRECT Project aims to obtain direct distances to two Local Group galaxies, M31 and M33, which occupy a crucial position near the bottom of the cosmological distance ladder. The first step is to search for detached eclipsing binaries…
The distance to the Galactic center inferred from OGLE RR Lyrae variables observed in the direction of the bulge is Ro=8.1+-0.6 kpc. An accurate determination of Ro is hindered by countless effects that include an ambiguous extinction law,…
(Abridged) We present the results of a new search for variable stars in the Local Group (LG) isolated dwarf galaxy IC1613, based on 24 orbits of F475W and F814W photometry from the ACS camera onboard the HST. We detected 259 candidate…
The fifth part of the OGLE-III Catalog of Variable Stars presents 23 R CrB (RCB) stars in the Large Magellanic Cloud (LMC). 17 of these objects have been spectroscopically confirmed by previous studies, while 6 stars are new candidates for…
We review the local determination of the Hubble constant, H$_0$, focusing on recent measurements of a distance ladder constructed from geometry, Cepheid variables and Type Ia supernovae (SNe Ia). We explain in some detail the components of…
This is the first of two papers reporting measurements from a program to determine the Hubble constant to 5% precision from a refurbished distance ladder. We present new observations of 110 Cepheid variables in the host galaxies of two…
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.…
We present photometry of 30 Galactic RR Lyrae variables taken with HST WFC3/IR for the Carnegie-Chicago Hubble Program. These measurements form the base of the distance ladder measurements that comprise a pure Population II base to a…
The eighth part of the OGLE-III Catalog of Variable Stars (OIII-CVS) contains type II Cepheids in the Small Magellanic Cloud (SMC). The sample consists of 43 objects, including 17 BL Her, 17 W Vir and 9 RV Tau stars (first examples ever…
The Galactic center (GC) is the densest region of the Milky Way. Variability surveys towards the GC potentially provide the largest number of variable stars per square degree within the Galaxy. However, high stellar density is also a…
The VMC survey is obtaining multi-epoch photometry in the Ks band of the Magellanic System down to a limiting magnitude of Ks ~ 19.3 for individual epoch data. The observations are spaced in time such as to provide optimal sampling of the…
The distance to the Large Magellanic Cloud (LMC) represents a key local rung of the extragalactic distance ladder. Yet, the galaxy's distance modulus has long been an issue of contention, in particular in view of claims that most newly…
Type II Cepheids are both useful distance indicators and tracers of old age stellar populations in their host galaxy. We summarize near-infrared observations of type II Cepheids in the Large Magellanic Cloud and discuss the absolute…
This work presents the charge-coupled device (CCD) photometric survey of the old open cluster NGC 188. Time-series V-band photometric observations were conducted for ten nights in January 2017 using the Nanshan One-meter Wide-field…
I concisely review the history, applications, and recent developments pertaining to radial velocity (RV) observations of classical pulsating stars. The focus lies on type-I (classical) Cepheids, although the historical overview and most…
Recent progress in the studies of pulsating variable stars is summarized from an observational point of view. A number of unexpected phenomena have been revealed in the case of pulsators in the classical instability strip. These discoveries…
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…
While the recent discovery of the Cepheid variables in the Virgo cluster galaxies puts additional support for the Hubble constant $H_0 \sim 80$km/sec/Mpc, a relatively lower value $H_0 \sim 50$km/sec/Mpc is suggested by other distance…
We present new large samples of Galactic Cepheids and RR Lyrae stars from the OGLE Galaxy Variability Survey.
We identified a sample of 88 bona fide Population II Cepheids (henceforth referred to as Cepheids) and 44 candidates in Galactic globular clusters (GCs). Seventy-eight of the Cepheids in the sample align within $2\,\sigma$ of the…