Browsing by Author "Borissova, Jura"
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- ItemDiscovery of new companions to high proper motion stars from the VVV Survey(2013) Ivanov, Valentín D.; Minniti, D.; Hempel, Maren; Kurtev, Radostín; Toledo, Ignacio; Saito, Roberto K.; García, Javier Alonso; Beamin, Juan Carlos; Borissova, Jura; Catelan, Márcio; Chene, André Nicolas; Emerson, Jin; González, Óscar A.; Lucas, Phillip W.; Martín, Eduardo L.; Rejkuba, Marina; Gromadzki, Mariusz
- ItemRGB Properties of the LMC/SMC Clusters in the Infrared(2009) Kurtev, Radostin; Ivanov, Valentin; Borissova, Jura; Catelan , Marcio; Geisler, Douglas
- ItemRR Lyrae in the LMC: Insights Into the Oosterhoff Phenomenon(2013) Kuehn, Charles A; Smith, Horace A.; Catelan, Marcio; Jeon, Young-Beom; Nemec, James M.; Walker, Alistair R.; Kunder, Andrea; Dame, Kyra; Pritzl, Barton J.; De Lee, Nathan; Borissova, JuraAlthough more than eight decades have passed since P. Th. Oosterhoff drew attention to differences in the properties of RR Lyrae variables in globular clusters, the origin and significance of the Oosterhoff groups remain unclear. Nonetheless, the accumulation of extensive new observations of RR Lyrae stars in globular clusters of the Milky Way and Local Group galaxies allows a fresh look at the phenomenon. Insights come not only from surveys of variables within the original Oosterhoff groups I and II but also from recent observations of the Oosterhoff-intermediate systems found especially in smaller Local Group galaxies. We will compare properties of RR Lyrae in several systems to investigate what they reveal about system-to-system differences of transition temperature between fundamental-mode and first overtone pulsators and of horizontal branch luminosity. Both transition temperature and horizontal branch luminosity have at various times been credited as playing roles in the creation of the Oosterhoff dichotomy....
- ItemVariable stars in the Galactic center, as revealed by the VVV Survey(2017) Molina, Claudio Navarro; Borissova, Jura; Catelan, Márcio; Kurtev, Radostin; Medina, NicolásA variability search has been performed in the Galactic center, using the nearinfrared images from the Vista Variables in the Vía Láctea (VVV) Survey. Light curves contain 89 epochs in the KS band. A total of 353 variable stars were found, of which only 47 are already present in the literature.
- ItemVariable stars in the VVV globular clusters. II. NGC 6441, NGC 6569, NGC 6626 (M 28), NGC 6656 (M 22), 2MASS-GC 02, and Terzan 10(2021) Alonso-García, Javier; Smith, Leigh C.; Catelan, Márcio; Minniti, Dante; Navarrete, Camila; Borissova, Jura; Carballo-Bello, Julio A.; Contreras Ramos, Rodrigo; Fernández-Trincado, José G.; Ferreira Lopes, Carlos E.; Gran, Felipe; Garro, Elisa R.; Geisler, Doug; Guo, Zhen; Hempel, Maren; Kerins, Eamonn; Lucas, Philip W.; Palma, Tali; Peña Ramírez, Karla; Ramírez Alegría, Sebastián; Saito, Roberto K.Context. The Galactic globular clusters (GGCs) located in the inner regions of the Milky Way suffer from high extinction that makes their observation challenging. High densities of field stars in their surroundings complicate their study even more. The VISTA Variables in the Via Lactea (VVV) survey provides a way to explore these GGCs in the near-infrared where extinction effects are highly diminished. Aims: We conduct a search for variable stars in several inner GGCs, taking advantage of the unique multi-epoch, wide-field, near-infrared photometry provided by the VVV survey. We are especially interested in detecting classical pulsators that will help us constrain the physical parameters of these GGCs. In this paper, the second of a series, we focus on NGC 6656 (M 22), NGC 6626 (M 28), NGC 6569, and NGC 6441; these four massive GGCs have known variable sources, but quite different metallicities. We also revisit 2MASS-GC 02 and Terzan 10, the two GGCs studied in the first paper of this series. Methods: We present an improved method and a new parameter that efficiently identify variable candidates in the GGCs. We also use the proper motions of those detected variable candidates and their positions in the sky and in the color-magnitude diagrams to assign membership to the GGCs. Results: We identify and parametrize in the near-infrared numerous variable sources in the studied GGCs, cataloging tens of previously undetected variable stars. We recover many known classical pulsators in these clusters, including the vast majority of their fundamental mode RR Lyrae. We use these pulsators to obtain distances and extinctions toward these objects. Recalibrated period-luminosity-metallicity relations for the RR Lyrae bring the distances to these GGCs to a closer agreement with those reported by Gaia, except for NGC 6441, which is an uncommon Oosterhoff III GGC. Recovered proper motions for these GGCs also agree with those reported by Gaia, except for 2MASS-GC 02, the most reddened GGC in our sample, where the VVV near-infrared measurements provide a more accurate determination of its proper motions. Lightcurves and full Tables 2, 5, 6, 7, 8, and 9 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/651/A47...