Related papers: 3D maps of the Magellanic Clouds using Classical C…

Anomalous Cepheids (ACs) are less studied metal-poor pulsating stars ([Fe/H]<-1.5) compared to Classical Cepheids (CCs) and RR Lyrae stars. They follow distinct Period-Luminosity (PL) and Period-Wesenheit (PW) relations and pulsate in…

The VISTA near-infrared $YJK_\mathrm{s}$ survey of the Magellanic Clouds System (VMC, PI M.-R. L. Cioni) is collecting deep $K_\mathrm{s}$-band time-series photometry of the pulsating variable stars hosted in the system formed by the two…

Classical Cepheids are blue loop stars that have famously been dubbed "magnifying glasses of stellar evolution" and have been studied for a long time. As more and more precise observations of Cepheids are secured over ever-increasing…

We employ the very recent photometric data of the OGLE project together with stellar atmosphere and linear pulsation models to determine the distance modulus of the Small Magellanic Cloud from its double-mode Cepheids. Based on the…

We use double-mode RR Lyrae (RRd) stars from the MACHO variable star database of the Large Magellanic Cloud (LMC) to estimate its distance, by utilizing photometric data, linear pulsation and stellar atmosphere models. If we set…

Classical Cepheids are key probes of both stellar astrophysics and cosmology as standard candles and pulsating variable stars. It is important to understand Cepheids in unprecedented detail in preparation for upcoming GAIA, JWST and…

We review the phenomenology of classical Cepheids (CCs), Anomalous Cepheids (ACs) and type II Cepheids (TIICs) in the Milky Way (MW) and in the Magellanic Clouds (MCs). We also examine the Hertzsprung progression in different stellar…

We present the OGLE-III Photometric Maps of the Large Magellanic Cloud. They cover about 40 square degrees of the LMC and contain mean, calibrated VI photometry and astrometry of about 35 million stars observed during seven observing…

We present an updated three dimensional map of the Milky Way based on a sample of 2431 classical Cepheid variable stars, supplemented with about 200 newly detected classical Cepheids from the OGLE survey. The new objects were discovered as…

We investigate the influence of blending on the Cepheid distance scale. Blending leads to systematically low distances to galaxies observed with HST, and therefore to systematically high estimates of the Hubble constant H_0. We select a…

We present a catalog of over 6.2 million stars with measured proper motions. All these stars are observed in the direction of the Magellanic Clouds within the brightness range 12 < I < 19 mag. Based on these proper motions about 440 000…

The 3D structure of the inner Small Magellanic Cloud (SMC) is investigated using the red clump (RC) stars and the RR Lyrae stars (RRLS). The V and I pass bands photometric data from the Optical Gravitational Lensing Experiment (OGLE III)…

We present an overview of our study of the short period variable stars in the Large Magellanic Cloud, and in the dwarf galaxies Fornax, Leo I, and NGC 6822. Light curves are presented for RR Lyrae stars, Anomalous Cepheids and, for the…

In the era of precision cosmology, it is essential to empirically determine the Hubble constant with an accuracy of one per cent or better. At present, the uncertainty on this constant is dominated by the uncertainty in the calibration of…

The Milky Way's neutral hydrogen (HI) disk is warped and flared. However, a dearth of accurate HI-based distances has thus far prevented the development of an accurate Galactic disk model. Moreover, the extent to which our Galaxy's stellar…

Classical Cepheid and RR Lyrae variables are fundamental tracers of cosmic distances and stellar evolution and pulsation. Light curve analysis and pulsation properties of these radially pulsating stars provide stringent tests for…

The main goal of our project is to investigate the spatial distribution of different stellar populations in the Magellanic Clouds. The results from modelling the Magellanic Clouds can be useful, among others, for simulations during the Gaia…

The primary distance indicators are established in our Galaxy and the Local Group. There are at least four different methods which give good distances: methods using proper motions, RR Lyraes, Cepheid variables, and Type II supernovae.…

We use the recently released OGLE-III catalog of 17692 fundamental mode RR Lyr (RRab) stars in the Large Magellanic Cloud (LMC) to investigate the structure of its stellar halo. We apply conservative cuts in period, amplitude and magnitude…

Classical Cepheid stars have been considered since more than a century as reliable tools to estimate distances in the universe thanks to their Period-Luminosity (P-L) relationship. Moreover, they are also powerful astrophysical…