Related papers: The Optical Gravitational Lensing Experiment. Vari…

Frequency analysis of more than 300 stars of the OGLE database on Sculptor galaxy has led to the discovery of 18 double-mode RR Lyrae (RRd) variables. This yields a 20% incidence rate for double-mode pulsation among the variables previously…

We present here a detailed study of the Sculptor dSph galaxy red giant branch (RGB) and horizontal branch (HB) morphology, combining new near-infrared photometry from CIRSI, with optical data from the ESO WFI. For a Sculptor-like old and…

We identified and characterized the largest (536) RR Lyrae (RRL) sample in a Milky Way dSph satellite (Sculptor) based on optical photometry data collected over $\sim$24 years. The RRLs display a spread in V-magnitude ($\sim$0.35 mag) which…

We present the identification of 634 variable stars in the Milky Way dSph satellite Sculptor based on archival ground-based optical observations spanning $\sim$24 years and covering $\sim$ 2.5 deg$^2$. We employed the same methodologies as…

We present a new homogeneous survey of VLT/FLAMES LR8 line-of-sight radial velocities (vlos) for 1604 resolved red giant branch stars in the Sculptor dwarf spheroidal galaxy. In addition, we provide reliable Ca II triplet metallicities,…

The results of a wide-field survey of the Sculptor dwarf spheroidal galaxy are presented. Our aims were to obtain an accurate map of the outer structure of Sculptor, and to determine the level of interaction between this system and the…

The ninth part of the OGLE-III Catalog of Variable Stars (OIII-CVS) comprises RR Lyr stars in the Small Magellanic Cloud (SMC). Our sample consists of 2475 variable stars, of which 1933 pulsate in the fundamental mode (RRab), 175 are the…

The eleventh part of the OGLE-III Catalog of Variable Stars (OIII-CVS) contains 16836 RR Lyr stars detected in the OGLE fields toward the Galactic bulge. The total sample is composed of 11756 RR Lyr stars pulsating in the fundamental mode…

We present the metallicity distribution of a sample of 471 RR Lyrae (RRL) stars in the Sculptor dSph, obtained from the $I$-band Period-Luminosity relation. It is the first time that the early chemical evolution of a dwarf galaxy is…

We have undertaken a search for variable stars in the metal-rich globular cluster NGC 6441 using time-series BV photometry. The total number of variables found near NGC 6441 has been increased to ~104, with 48 new variables being found in…

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…

We have obtained single-phase near-infrared magnitudes in the J and K bands for a sample of 78 RR Lyrae stars in the Sculptor dSph galaxy. Applying different theoretical and empirical calibrations of the period-luminosity-metallicity…

We present a CCD survey of variable stars in the Draco dwarf spheroidal galaxy. This survey, which has the largest areal coverage since the original variable star survey by Baade & Swope, includes photometry for 270 RR Lyrae stars, 9…

(Abridged) We explore the spatial distribution of stars in the Sculptor dwarf spheroidal (dSph) galaxy over an area of 7.82 deg^2. We identify red giant branch (RGB) starts via Washington M, T_2+DDO51 photometry and a blue horizontal branch…

We present a search and analysis of variable stars in the recently discovered Crater~II dwarf galaxy. Based on $B$, $V$, $I$ data collected with the Isaac Newton Telescope (FoV$\sim$0.44 square degrees) we detected 37 variable stars, of…

We have used high-resolution, high signal-to-noise spectra obtained with the VLT and UVES to determine abundances of 17 elements in 4 red giants in the Sculptor dwarf spheroidal galaxy. Our [Fe/H] values range from --2.10 to --0.97,…

BV photometry is presented for 12 RR Lyr variables discovered in the presumably young galactic globular cluster Ruprecht 106. All variables are type RRab, and their periods span a narrow range from 0.574 to 0.652 day. We report also on the…

(abridged): Low resolution spectroscopy obtained with FORS2 at the Very Large Telescope (VLT) has been used to measure individual metal abundances ([Fe/H]) for 107 RR Lyrae stars, and trace the metal distribution of the oldest stellar…

We use the fundamental-mode RR Lyr-type variable stars (RRab) from OGLE-IV survey to draw a 3D picture of the central part of the tidally disrupted Sagittarius Dwarf Spheroidal (Sgr dSph) galaxy. We estimate the line-of-sight thickness of…

We have performed the first detailed simulation of the horizontal branch of the Sculptor dwarf spheroidal galaxy by means of synthetic modelling techniques,taking consistently into account the star formation history and metallicity…