Browsing by Author "Angeloni, R."

Now showing 1 - 8 of 8
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    The spectral energy distribution of D-type symbiotic stars: the role of dust shells
    (2010) Angeloni, R.; Contini, M.; Ciroi, S.; Rafanelli, P.
    We have collected continuum data of a sample of D-type symbiotic stars. By modelling their spectral energy distribution in a colliding-wind theoretical scenario we have found characteristics common to all the systems: (1) at least two dust shells are clearly present, one at similar to 1000 K and the other at similar to 400 K; they dominate the emission in the infrared; (2) the radio data are explained by thermal self-absorbed emission from the reverse shock between the stars; while (3) the data in the long wavelength tail come from the expanding shock outwards the system; (4) in some symbiotic stars, the contribution from the white dwarf in the UV is directly seen. Finally, (5) for some objects soft X-ray emitted by bremsstrahlung downstream of the reverse shock between the stars is predicted. The results thus confirm the validity of the colliding-wind model and the important role of the shocks. The comparison of the fluxes calculated at the nebula with those observed at the Earth reveals the distribution throughout the system of the different components, in particular the nebulae and the dust shells. The correlation of shell radii with the orbital period shows that larger radii are found at larger periods. Moreover, the temperatures of the dust shells regarding the sample are found at similar to 1000 and < 400 K, while in the case of late giants they spread more uniformly throughout the same range.
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    The Vista Variables in the Vía Láctea (VVV) ESO Public Survey: Current Status and First Results
    (2011) Catelan, Marcio; Minniti, D.; Lucas, P. W.; Alonso-García, J.; Angeloni, R.; Beamín, J. C.; Bonatto, C.; Borissova, J.; Contreras, C.; Cross, N.; Dékáany, I.; Emerson, J. P.; Eyheramendy, S.; Geisler, D.; González-Solares, E.; Helminiak, K. G.; Hempel, M.; Irwin, M. J.; Ivanov, V. D.; Jordán, A.; Kerins, E.; Kurtev, R.; Mauro, F.; Moni Bidin, C.; Navarrete, C.; Pérez, P.; Pichara, K.; Read, M.; Rejkuba, M.; Saito, R. K.; Sale, S. E.; Toledo, I.
    Vista Variables in the Vía Láctea (VVV) is an ESO Public Survey that is performing a variability survey of the Galactic bulge and part of the inner disk using ESO's Visible and Infrared Survey Telescope for Astronomy (VISTA). The survey covers 520 { deg}^2 of sky area in the ZYJHK_S filters, for a total observing time of 1929 hours, including ∼ 10^9 point sources and an estimated ∼ 10^6 variable stars. Here we describe the current status of the VVV Survey, in addition to a variety of new results based on VVV data, including light curves for variable stars, newly discovered globular clusters, open clusters, and associations. A set of reddening-free indices based on the ZYJHK_S system is also introduced. Finally, we provide an overview of the VVV Templates Project, whose main goal is to derive well-defined light curve templates in the near-IR, for the automated classification of VVV light curves....
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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 Survey of the Milky Way: first year results
    (2011) Minniti, D.; Clariá, J. J.; Saito, R. K.; Hempel, M.; Lucas, P. W.; Rejkuba, M.; Toledo, I.; Gonzalez, O. A.; Alonso-García, J.; Irwin, M. J.; Gonzalez-Solares, E.; Cross, N.; Ivanov, V. D.; Soto, M.; Dékány, I.; Angeloni, R.; Catelan, Marcio; Amôres, E. B.; Gurovich, S.; Emerson, J. P.; Lewis, J.; Hodgkin, S.; Pietrukowicz, P.; Zoccali, M.; Sale, S. E.; Barbá, R.; Barbuy, B.; Beamin, J. C.; Helminiak, K.; Borissova, J.; Folkes, S. L.; Gamen, R. C.; Geisler, D.; Mauro, F.; Chené, A. -N.; Alonso, M. V.; Gunthardt, G.; Hanson, M.; Kerins, E.; Kurtev, R.; Majaess, D.; Martín, E.; Masetti, N.; Mirabel, I. F.; Monaco, L.; Moni Bidin, C.; Padilla, N.; Rojas, A.; Pietrzynski, G.; Saviane, I.; Valenti, E.; Weidmann, W.; López-Corredoira, M.; Ahumada, A. V.; Aigrain, S.; Arias, J. I.; Bica, E.; Bandyopadhyay, R. M.; Baume, G.; Bedin, L. R.; Bonatto, C.; Bronfman, L.; Carraro, G.; Contreras, C.; Davis, C. J.; de Grijs, R.; Dias, B.; Drew, J. E.; Fariña, C.; Feinstein, C.; Fernández Lajús, E.; Gieren, W.; Goldman, B.; Gosling, A.; Hambly, N. C.; Hoare, M.; Jordán, A.; Kinemuchi, K.; Maccarone, T.; Merlo, D. C.; Mennickent, R. E.; Morelli, L.; Motta, V.; Palma, T.; Popescu, B.; Parisi, M. C.; Parker, Q.; Pignata, G.; Read, M. A.; Ruiz, M. T.; Roman-Lopes, A.; Schreiber, M. R.; Schröder, A. C.; Smith, M.; Sodré, L., Jr.; Stephens, A. W.; Walton, N. A.; Zijlstra, A. A.; Tamura, M.; Tappert, C.; Thompson, M. A.; Vanzi, L.
    The VISTA Variables in the Via Lactea (VVV) is an ESO public near-IR variability survey that is scanning the Milky Way bulge and an adjacent section of the Galactic mid-plane. The survey will take 1929 hours of observations with the VISTA 4.1-m telescope during five years, covering a billion point sources across an area of 520 sqdeg, including 36 known globular clusters and more than 350 open clusters. The final product will be a deep IR atlas in five passbands (0.9 - 2.5 microns) and a catalogue of more than a million variable point sources....
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    The VVV Templates Project
    (2014) Contreras Ramos, R.; Catelan, Marcio; Gran, F.; Navarrete, C.; Angeloni, R.; Alonso-García, J.; Dékány, I.; Hajdu, G.; Hempel, M.; Jordán, A.; Townsend, B.; Borissova, J.; Navarro, C.; Pichara, K.; Eyheramendy, S.
    Until now, stellar variability in the near-IR has been a relatively ill-explored research field. In particular, the number of high-quality light curves is very limited and, even worse, many variability classes have not yet been observed in a sufficiently extensive way in the near-IR, so that good light curves are entirely lacking for some such classes. Since VVV is the first ever large survey dedicated to stellar variability in the near-infrared, the first problem we had to face has thus been the construction of a proper statistically significant database of high-quality (i.e., template) near-IR light curves for a significant sample of stars taken to be representative of the different variability classes under study. The main purpose of the VVV Templates Project is thus to build a large database of well-defined, high-quality, near-IR light curves for variable stars of different types, which will form the basis of the VVV automated classification algorithms...
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    The VVV Templates Project Towards Automated Classification of VVV Light Curves
    (2011) Catelan, Marcio; Angeloni, R.; Dékány, I.; Pichara, K.; Eyheramendy, S.; Borissova, J.
    The main goal of the VVV Templates Project is to build a large database of well-defined, high-quality near-IR light curves for variable stars of different types, which will form the basis of the VVV automated classification algorithms.
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    VISTA Variables in the Via Lactea (VVV): Current Status and First Results
    (2010) Saito, R.; Hempel, M.; Alonso-García, J.; Toledo, I.; Borissova, J.; González, O.; Beamin, J. C.; Minniti, D.; Lucas, P.; Emerson, J.; Ahumada, A.; Aigrain, S.; Alonso, M. V.; Amôres, E.; Angeloni, R.; Arias, J.; Bandyopadhyay, R.; Barbá, R.; Barbuy, B.; Baume, G.; Bedin, L.; Bica, E.; Bronfman, L.; Carraro, G.; Catelan, Marcio; Clariá, J.; Contreras, C.; Cross, N.; Davis, C.; de Grijs, R.; Dékány, I.; Janet Drew, J. D.; Fariña, C.; Feinstein, C.; Fernández Lajús, E.; Folkes, S.; Gamen, R.; Geisler, D.; Gieren, W.; Goldman, B.; Gosling, A.; Gunthardt, G.; Gurovich, S.; Hambly, N.; Hanson, M.; Hoare, M.; Irwin, M.; Ivanov, V.; Jordán, A.; Kerins, E.; Kinemuchi, K.; Kurtev, R.; Longmore, A.; López-Corredoira, M.; Maccarone, T.; Martín, E.; Masetti, N.; Mennickent, R.; Merlo, D.; Messineo, M.; Mirabel, F.; Monaco, L.; Moni Bidin, C.; Morelli, L.; Padilla, N.; Palma, T.; Parisi, M. C.; Parker, Q.; Pavani, D.; Pietrukowicz, P.; Pietrzynski, G.; Pignata, G.; Rejkuba, M.; Rojas, A.; Roman Lopes, A.; Ruiz, M. T.; Sale, S.; Saviane, I.; Schreiber, M.; Schröder, A.; Sharma, S.; Smith, M.; Sodré, L., Jr.; Soto, M.; Stephens, A.; Tamura, M.; Tappert, C.; Thompson, M.; Valenti, E.; Vanzi, L.; Weidmann, W.; Zoccali, M.
    VISTA Variables in the Vía Láctea (VVV) is a public ESO near-IR variability survey aimed at scanning the Milky Way Bulge and an adjacent section of the mid-plane. VVV observations started in October 2009 during ESO science verification. Regular observations for the first year of the survey have been conducted since February 2010 and will cover a total area of 520 square degrees in five passbands and five epochs. Here we address the first results obtained from the VVV Survey as well as the current status of the observations....
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    Vista variables in the via lactea (VVV): first results and perspectives
    (2011) Saito, R. K.; Minniti, D.; Dekany, I.; Hempel, M.; Alonso-Garcia, J.; Toledo, I.; Beamin Muhlenbrock, Juan Carlos; Angeloni, R.; Lucas, P. W.; Emerson, J. P.
    VISTA Variables in the Via Lactea (VVV) is a public ESO near-IR variability survey scanning the Milky Way Bulge and an adjacent section of the mid-plane. The survey will take 1929 hours of observations with the 4 m VISTA telescope during five years (2010-2014), covering similar to 10(9) point sources across an area of 520 deg(2). Here we address the first results obtained from the VVV Survey as well as a glimpse into the possibilities for using a deep near-IR atlas in five passbands and a catalogue of more than 10(6) variable point sources. We expect to use the data to find planetary transits of late-type main-sequence stars. We discuss the planet searches and future follow-ups