Related papers: RR Lyrae variables in Omega Centauri: a theoretica…
We present a comprehensive analysis of the variable stars projected on the field of the Galactic bulge globular cluster NGC 6522, offering valuable insights into their characteristics. Using proper motions from Gaia DR3, we aim to…
We report the mean metallicity and absolute magnitude of RR Lyrae stars in a sample of 37 globular clusters, calculated via the Fourier decomposition of their light curves and ad hoc semiempirical calibrations, in an unprecedented…
We present a long-term project aimed at completing the census of (bright) variable stars in Galactic globular clusters. While our main aim is to obtain a reliable assessment of the populations of RR Lyrae and type II Cepheid stars in the…
We present an analysis of \emph{VI} CCD time-series photometry of the Oo II type globular cluster M92. The variable star population of the cluster is studied with the aim of revising their classifications, identifications, frequency spectra…
We present a new set of tools to derive systemic velocities for single-mode RR~Lyrae stars from visual and near-infrared spectra. We derived scaling relations and line-of-sight velocity templates using both APOGEE and {\it Gaia}…
We present 20 newly discovered candidates for binary systems with an RR~Lyrae companion. Using the photometric data from the Optical Gravitational Lensing Experiment (OGLE) and Korea Microlensing Telescope Network (KMTNet) for the Galactic…
[ABRIDGED] $\omega$ Centauri (NGC 5139) contains large numbers of variable stars of different types and, in particular, more than a hundred RR Lyrae stars. We have conducted a variability survey of $\omega$ Cen in the NIR, using ESO's 4.1m…
We present a new framework for modelling discrete kinematic data. Current techniques typically involve binning. Our approach works directly with the discrete data and uses maximum-likelihood methods to assess the probability of the dataset…
We report an analysis of new $V$ and $I$ CCD time-series photometry of the globular cluster NGC 6934. Through the Fourier decomposition of the RR Lyrae light curves, the mean values of [Fe/H] and the distance of the cluster were estimated,…
Context. A number of RR Lyrae stars show variable mean magnitudes in the OGLE survey light curves of the Galactic bulge. Hitherto this phenomenon was not studied, as it was generally assumed to be related to problems with the photometry.…
Recent Hipparcos results have lent support to the idea that RR Lyrae variables in the halo field and in globular clusters differ in luminosity by ~0.2mag. In this Letter, we study the pulsation properties of RR Lyraes in clusters with…
We present time-series B, V photometry of NGC 6229, obtained with the purpose of providing the first extensive CCD variability study of this cluster. As a result, we were able to obtain periods for all NGC 6229 variables, with the exception…
A rich harvest of RR Lyrae stars has been identified for the first time in B514, a metal-poor ([Fe/H] = 1.95 +/- 0.10 dex) globular cluster of the Andromeda galaxy (M31), based on Hubble Space Telescope Wide Field Planetary Camera 2 and…
We present some recent findings concerning the use of RR Lyrae as distance indicators and stellar tracers. We outline pros and cons of field and cluster RR Lyrae stars and discuss recent theoretical findings concerning the use of the Bailey…
We present a careful and detailed light curve analysis of RR Lyrae stars in the Small Magellanic Cloud (SMC) discovered by the Optical Gravitational Lensing Experiment (OGLE) project. Out of 536 single mode RR Lyrae stars selected from the…
RR Lyrae stars play an important role as distance indicators and stellar population tracers. In this context the construction of accurate pulsation models is crucial to understand the observed properties and to constrain the intrinsic…
The first calibrated broadband UBVI time-series photometry is presented for the RR Lyrae variable stars in NGC6656 (M22), with observations spanning a range of twenty-two years. We have also redetermined the variability types and periods…
A search for variable stars in the globular cluster NGC 288 was carried out using a time-series of CCD images in the $V$ and $I$ filters. The photometry of all stellar sources in the field of view of our images, down to $V\approx19$ mag,…
We present time-series $BVI$ photometry for the Galactic globular cluster NGC 6402 (M14). The data consists of $\sim$137 images per filter, obtained using the 0.9m and 1.0m SMARTS telescopes at the Cerro Tololo Inter-American Observatory.…
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…