Browsing by Author "Catelan, M."

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    Deep HST photometry of NGC 6388
    (2006) Catelan, M.; Stetson, Peter B.; Pritzl, Barton J.; Smith, Horace A.; Kinemuchi, Karen; Layden, Andrew C.; Sweigart, Allen V.; Rich, R. M.
    Using the Hubble Space Telescope, we have obtained the first color-magnitude diagram (CMD) to reach the main-sequence turnoff of the Galactic globular cluster NGC 6388. From a comparison between the cluster CMD and that of 47 Tucanae, we find that the bulk of the stars in these two clusters have nearly the same age and chemical composition. On the other hand, our results indicate that the blue horizontal branch and RR Lyrae components in NGC 6388 are intrinsically overluminous, which must be due to one or more, still undetermined, noncanonical second parameter(s) affecting a relatively minor fraction of the stars in NGC 6388.
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    Discovery of VVV CL001 A low-mass globular cluster next to UKS 1 in the direction of the Galactic bulge
    (EDP SCIENCES S A, 2011) Minniti, D.; Hempel, M.; Toledo, I.; Ivanov, V. D.; Alonso Garcia, J.; Saito, R. K.; Catelan, M.; Geisler, D.; Jordan, A.; Borissova, J.; Zoccali, M.; Kurtev, R.; Carraro, G.; Barbuy, B.; Claria, J.; Rejkuba, M.; Emerson, J.; Moni Bidin, C.
    Context. It is not known how many globular clusters may remain undetected towards the Galactic bulge.
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    Humps and bumps: the effects of shocks on the optical light curves of fundamental-mode RR Lyrae stars
    (EDP SCIENCES S A, 2020) Prudil, Z.; Dekany, I.; Smolec, R.; Catelan, M.; Grebel, E. K.; Kunder, A.
    We present the most extended and homogeneous study carried out so far of the main and early shocks in 1485 RR Lyrae stars in the Galactic bulge observed by the Optical Gravitational Lensing Experiment. We selected nonmodulated fundamental-mode RR Lyrae stars with good-quality photometry. Using a self-developed method, we determined the centers and strengths of main and early shock features in the phased light curves. We found that the positions of both humps and bumps are highly correlated with the pulsation properties of the studied variables. Pulsators with a pronounced main shock are concentrated in the low-amplitude regime of the period-amplitude diagram, while stars with a strong early shock have average and above-average pulsation amplitudes. A connection between the main and early shocks and the Fourier coefficients is also observed. In the color-magnitude diagram, we see a separation between stars with strong and weak shocks. Variables with a pronounced main shock cluster close to the fundamental red edge of the instability strip (IS), while stars with a strong early shock tend to clump in the center and near the fundamental blue edge of the IS. The appearance of shocks and their properties appear to be independent of the direction of evolution estimated from the period change rate of the studied stars. In addition, the differences in the period change rate between the two main Oosterhoff groups found in the Galactic bulge suggest that stars of Oosterhoff type I are located close to the zero-age horizontal branch while Oosterhoff type II variables are on their way toward the fundamental red edge of the instability strip, and have therefore already left the zero-age horizontal branch.
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    Informative Bayesian model selection for RR Lyrae star classifiers
    (2021) Pérez-Galarce, F.; Pichara, K.; Huijse, P.; Catelan, M.; Mery Quiroz, Domingo Arturo
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    Milky Way demographics with the VVV survey I. The 84-million star colour-magnitude diagram of the Galactic bulge
    (EDP SCIENCES S A, 2012) Saito, R. K.; Minniti, D.; Dias, B.; Hempel, M.; Rejkuba, M.; Alonso Garcia, J.; Barbuy, B.; Catelan, M.; Emerson, J. P.; Gonzalez, O. A.; Lucas, P. W.; Zoccali, M.
    Context. The Milky Way (MW) bulge is a fundamental Galactic component for understanding the formation and evolution of galaxies, in particular our own. The ESO Public Survey VISTA Variables in the Via Lactea is a deep near-IR survey mapping the Galactic bulge and southern plane. Particularly for the bulge area, VVV is covering similar to 315 deg(2). Data taken during 2010 and 2011 covered the entire bulge area in the JHKs bands.
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    The VISTA Variables in the Via Lactea extended (VVVX) ESO public survey: Completion of the observations and legacy
    (2024) Saito, R. K.; Hempel, M.; Alonso-Garcia, J.; Lucas, P. W.; Minniti, D.; Alonso, S.; Baravalle, L.; Borissova, J.; Caceres, C.; Chene, A. N.; Cross, N. J. G.; Duplancic, F.; Garro, E. R.; Gomez, M.; Ivanov, V. D.; Kurtev, R.; Luna, A.; Majaess, D.; Navarro, M. G.; Pullen, J. B.; Rejkuba, M.; Sanders, J. L.; Smith, L. C.; Albino, P. H. C.; Alonso, M. V.; Amores, E. B.; Angeloni, R.; Arias, J. I.; Arnaboldi, M.; Barbuy, B.; Bayo, A.; Beamin, J. C.; Bedin, L. R.; Bellini, A.; Benjamin, R. A.; Bica, E.; Bonatto, C. J.; Botan, E.; Braga, V. F.; Brown, D. A.; Cabral, J. B.; Camargo, D.; Garatti, Caratti O. A.; Carballo-Bello, J. A.; Catelan, M.; Chavero, C.; Chijani, M. A.; Claria, J. J.; Coldwell, G. V.; Pena, C. Contreras; Contreras Ramos, R.; Corral-Santana, J. M.; Cortes, C. C.; Cortes-Contreras, M.; Cruz, P.; Daza-Perilla, I. V.; Debattista, V. P.; Dias, B.; Donoso, L.; D'Souza, R.; Emerson, J. P.; Federle, S.; Fermiano, V.; Fernandez, J.; Fernandez-Trincado, J. G.; Ferreira, T.; Ferreira Lopes, C. E.; Firpo, V.; Flores-Quintana, C.; Fraga, L.; Froebrich, D.; Galdeano, D.; Gavignaud, I.; Geisler, D.; Gerhard, O. E.; Gieren, W.; Gonzalez, O. A.; Gramajo, L. V.; Gran, F.; Granitto, P. M.; Griggio, M.; Guo, Z.; Gurovich, S.; Hilker, M.; Jones, H. R. A.; Kammers, R.; Kuhn, M. A.; Kumar, M. S. N.; Kundu, R.; Lares, M.; Libralato, M.; Lima, E.; Maccarone, T. J.; Marchant Cortes, P.; Martin, E. L.; Masetti, N.; Matsunaga, N.; Mauro, F.; McDonald, I.; Mejias, A.; Mesa, V.; Milla-Castro, F. P.; Minniti, J. H.; Moni Bidin, C.; Montenegro, K.; Morris, C.; Motta, V.; Navarete, F.; Navarro Molina, C.; Nikzat, F.; Nilo Castellon, J. L.; Obasi, C.; Ortigoza-Urdaneta, M.; Palma, T.; Parisi, C.; Pena Ramirez, K.; Pereyra, L.; Perez, N.; Petralia, I.; Pichel, A.; Pignata, G.; Ramirez Alegria, S.; Rojas, A. F.; Rojas, D.; Roman-Lopes, A.; Rovero, A. C.; Saroon, S.; Schmidt, E. O.; Schroeder, A. C.; Schultheis, M.; Sgro, M. A.; Solano, E.; Soto, M.; Stecklum, B.; Steeghs, D.; Tamura, M.; Tissera, P.; Valcarce, A. A. R.; Valotto, C. A.; Vasquez, S.; Villalon, C.; Villanova, S.; Vivanco Cadiz, F.; Zelada Bacigalupo, R.; Zijlstra, A.; Zoccali, M.
    Context. The ESO public survey VISTA Variables in the Via Lactea (VVV) surveyed the inner Galactic bulge and the adjacent southern Galactic disk from 2009-2015. Upon its conclusion, the complementary VVV extended (VVVX) survey has expanded both the temporal as well as spatial coverage of the original VVV area, widening it from 562 to 1700 sq. deg., as well as providing additional epochs in JHKs filters from 2016-2023.
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    The VVV Infrared Variability Catalog (VIVA-I)
    (2020) Ferreira Lopes, E. C.; Cross, N. J. G.; Catelan, M.; Minniti, D.; Hempel, M.; Lucas, W. P.; Angeloni, R.; Jablonsky, F.; Braga, F. V.; Leao, C. I.; Herpich, F. R.; Alonso-Garcia, J.; Papageorgiou, A.; Pichara, K.; Saito, K. R.; Bradley, A.; Beamin Muhlenbrock Juan Carlos; Cortes, C.; De Medeiros, J. R.; Russell, Christopher
    Thanks to the VISTA Variables in the Via Lactea (VVV) ESO Public Survey it is now possible to explore a large number of objects in those regions. This paper addresses the variability analysis of all VVV point sources having more than 10 observations in VVVDR4 using a novel approach. In total, the near-IR light curves of 288,378,769 sources were analysed using methods developed in the New Insight Into Time Series Analysis project. As a result, we present a complete sample having 44, 998, 752 variable star candidates (VVV-CVSC), which include accurate individual coordinates, near-IR magnitudes (ZYJHKs), extinctions A(Ks), variability indices, periods, amplitudes, among other parameters to assess the science. Unfortunately, a side effect of having a highly complete sample, is also having a high level of contamination by non-variable (contamination ratio of non-variables to variables is slightly over 10:1). To deal with this, we also provide some flags and parameters that can be used by the community to de-crease the number of variable candidates without heavily decreasing the completeness of the sample. In particular, we cross-identified 339,601 of our sources with Simbad and AAVSO databases, which provide us with information for these objects at other wavelegths. This sub-sample constitutes a unique resource to study the corresponding near-IR variability of known sources as well as to assess the IR variability related with X-ray and Gamma-Ray sources. On the other hand, the other 99.5% sources in our sample constitutes a number of potentially new objects with variability information for the heavily crowded and reddened regions of the Galactic Plane and Bulge. The present results also provide an important queryable resource to perform variability analysis and to characterize ongoing and future surveys like TESS and LSST.
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    Using classical Cepheids to study the far side of the Milky Way disk II. The spiral structure in the first and fourth Galactic quadrants
    (2021) Minniti, J. H.; Zoccali, M.; Rojas-Arriagada, A.; Minniti, D.; Sbordone, L.; Ramos, R. Contreras; Braga, V. F.; Catelan, M.; Duffau, S.; Gieren, W.; Marconi, M.; Valcarce, A. A. R.
    In an effort to improve our understanding of the spiral arm structure of the Milky Way, we use classical Cepheids (CCs) to increase the number of young tracers on the far side of the Galactic disk with accurately determined distances. We used a sample of 30 CCs that were discovered using near-infrared photometry from the VISTA Variables in the Via Lactea survey (VVV) and classified based on their radial velocities and metallicities. We combined them with another 20 CCs from the literature for which VVV photometry is available. We used the compiled sample of CCs with homogeneously computed distances based on VVV infrared photometry as a proof of concept to trace the spiral structure in the poorly explored far side of the disk. Although the use of CCs has some caveats, these variables are currently the only available young tracers on the far side of the disk for which a numerous sample with accurate distances can be obtained. Therefore, a larger sample could allow us to make a significant step forward in our understanding of the Milky Way disk as a whole. We present preliminary evidence that CCs favor the following: a spiral arm model with two main arms (Perseus and Scutum-Centaurus) that branch out into four arms at Galactocentric distances, R-GC >= 5-6 kpc; the extension of the Scutum-Centaurus arm behind the Galactic center; and a possible connection between the Perseus arm and the Norma tangency direction. The current sample of CCs on the far side of the Galaxy are in the mid-plane, which argues against the presence of a severely warped disk at small Galactocentric distances (R-GC <= 12 kpc) in the studied area. The discovery and characterization of CCs at near-infrared wavelengths appears to be a promising tool to complement studies based on other spiral arm tracers and extend them to the far side of our Galaxy.
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    VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way
    (ELSEVIER, 2010) Minniti, D.; Lucas, P. W.; Emerson, J. P.; Saito, R. K.; Hempel, M.; Pietrukowicz, P.; Ahumada, A. V.; Alonso, M. V.; Alonso Garcia, J.; Arias, J. I.; Bandyopadhyay, R. M.; Barba, R. H.; Barbuy, B.; Bedin, L. R.; Bica, E.; Borissova, J.; Bronfman, L.; Carraro, G.; Catelan, M.; Claria, J. J.; Cross, N.; de Grijs, R.; Dekany, I.; Drew, J. E.; Farina, C.; Feinstein, C.; Fernandez Lajus, E.; Gamen, R. C.; Geisler, D.; Gieren, W.; Goldman, B.; Gonzalez, O. A.; Gunthardt, G.; Gurovich, S.; Hambly, N. C.; Irwin, M. J.; Ivanov, V. D.; Jordan, A.; Kerins, E.; Kinemuchi, K.; Kurtev, R.; Lopez Corredoira, M.; Maccarone, T.; Masetti, N.; Merlo, D.; Messineo, M.; Mirabel, I. F.; Monaco, L.; Morelli, L.; Padilla, N.; Palma, T.; Parisi, M. C.; Pignata, G.; Rejkuba, M.; Roman Lopes, A.; Sale, S. E.; Schreiber, M. R.; Schroeder, A. C.; Smith, M.; Sodre, L., Jr.; Soto, M.; Tamura, M.; Tappert, C.; Thompson, M. A.; Toledo, I.; Zoccali, M.; Pietrzynski, G.
    We describe the public ESO near-IR variability survey (VVV) scanning the Milky Way bulge and an adjacent section of the mid-plane where star formation activity is high. The survey will take 1929 h of observations with the 4-m VISTA telescope during 5 years (2010-2014), covering similar to 10(9) point sources across an area of 520 deg(2), including 33 known globular clusters and similar to 350 open clusters. The final product will be a deep near-IR atlas in five passbands (0.9-2.5 mu m) and a catalogue of more than 106 variable point sources. Unlike single-epoch surveys that, in most cases, only produce 2-D maps, the VVV variable star survey will enable the construction of a 3-D map of the surveyed region using well-understood distance indicators such as RR Lyrae stars, and Cepheids. It will yield important information on the ages of the populations. The observations will be combined with data from MACHO, OGLE, EROS, VST, Spitzer, HST, Chandra, INTEGRAL, WISE, Fermi LAT, XMM-Newton, GAIA and ALMA for a complete understanding of the variable sources in the inner Milky Way. This public survey will provide data available to the whole community and therefore will enable further studies of the history of the Milky Way, its globular cluster evolution, and the population census of the Galactic Bulge and center, as well as the investigations of the star forming regions in the disk. The combined variable star catalogues will have important implications for theoretical investigations of pulsation properties of stars. (C) 2009 Elsevier B.V. All rights reserved.
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    VVV-WIT-01 : highly obscured classical nova or protostellar collision?
    (2020) Lucas, P. W.; Minniti, D.; Kamble, A.; Kaplan, D. L.; Cross, N.; Dekany, Istvan; Ivanov, V. D.; Kurtev, R.; Saito, R. K.; Smith, L. C.; Catelan, M.; Masetti, N.; Toledo, I.; Hempel, M.; Thompson, M. A.; Pena, C. C.; Forbrich, J.; Krause, M.; Dale, J.; Borissova, J.; Emerson, J.; Lucas, P. W.; Minniti, D.; Kamble, A.; Kaplan, D. L.; Cross, N.; Dekany, Istvan; Ivanov, V. D.; Kurtev, R.; Saito, R. K.; Smith, L. C.; Catelan, M.; Masetti, N.; Toledo, I.; Hempel, M.; Thompson, M. A.; Pena, C. C.; Forbrich, J.; Krause, M.; Dale, J.; Borissova, J.; Emerson, J.