Browsing by Author "Borissova, J."

Now showing 1 - 20 of 70
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    A colour-excess extinction map of the southern Galactic disc from the VVV and GLIMPSE surveys
    (2019) Soto, M.; Barba, R.; Minniti, D.; Kunder, A.; Majaess, D.; Nilo Castellon, J. L.; Alonso García, J.; Leone, G.; Contreras Ramos, Rodrigo Andrés; Hempel, Maren; Morelli, Lorenzo; Haikala, L.; Firpo, V.; Lucas, P.; Emerson, J. P.; Bidin, C. M.; Geisler, D.; Saito, R. K.; Gurovich, S.; Rejkuba, M.; Barbieri, M.; Román Lopes, A.; Alonso, M. V.; Baravalle, L. D.; Borissova, J.; Kurtev, R.; Milla, F
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    A deep near-infrared view of the Galactic globular cluster 2 MASS GC 02
    (2007) Borissova, J.; Catelan, Márcio; Minniti, D.
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    A near-infrared catalogue of the Galactic novae in the VVV survey area
    (2013) Kalbusch Saito, Roberto; Minniti, D.; Angeloni, Rodolfo; Catelan, Márcio; Beamin, J. C.; Borissova, J.; Dekany, Istvan; Kerins, E.; Kurtev, R.; Mennickent, R. E.
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    A Search for EHB Pulsators in the Globular Cluster NGC 6752
    (2007) Catelan , Marcio; Prieto, G. E.; Zoccali, M.; Weidner, C.; Stetson, P. B.; Moni Bidin, C.; Altmann, M.; Smith, H. A.; Pritzl, B. J.; Borissova, J.; de Medeiros, J. R.
    We describe the status of a project whose main goal is to detect variability along the extreme horizontal branch of the globular cluster NGC 6752. Based on Magellan 6.5-m data, preliminary light curves are presented for some candidate variables. By combining our time-series data, we also produce a deep CMD of unprecedented quality for the cluster which reveals a remarkable lack of main sequence binaries, possibly pointing to a low primordial binary fraction....
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    A SUBMILLIMETER STUDY OF THE IR DUST BUBBLE S 21 AND ITS ENVIRONS
    (UNIV NACIONAL AUTONOMA MEXICO, INST DE ASTRONOMIA, 2017) Cappa, C. E.; Duronea, N. U.; Vasquez, J.; Rubio, M.; Firpo, V.; Lopez Caraballo, C. H.; Borissova, J.
    Based on the molecular emission in the (CO)-C-12(2-1) and (CO)-C-13(2-1) lines, and on the continuum emission in the MIR and FIR towards the S 21 IR dust bubble, we analyze the physical characteristics of the gas and dust linked to the nebula and the presence of young stellar objects (YSOs) in its environs. The line emission reveals a clumpy molecular shell, 1.4 pc in radius, encircling S 21. The total molecular mass in the shell amounts to 2900 M-circle dot and the original ambient density, 2.1 x10(3) cm(-3), indicating that the bubble is evolving in a high density interstellar medium. The image at 24 mu m shows warm dust inside the bubble, while the emission in the range 250 to 870 mu m reveals cold dust in its outskirts, coincident with the molecular gas. The detection of radio continuum emission indicates that the bubble is a compact Hii region. A search for YSOs using photometric criteria allowed to identify many candidates projected onto the molecular clumps. We analize if the collect and collapse process has triggered a new generation of stars.
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    Alert Classification for the ALeRCE Broker System: The Light Curve Classifier
    (2021) Sánchez-Sáez, P.; Reyes, I.; Valenzuela, C.; Förster, F.; Eyheramendy, S.; Elorrieta, F.; Bauer, F. E.; Cabrera-Vives, G.; Estévez, P. A.; Catelan, Márcio; Pignata, G.; Huijse, P.; De Cicco, D.; Arévalo, P.; Carrasco-Davis, R.; Abril, J.; Kurtev, R.; Borissova, J.; Arredondo, J.; Castillo-Navarrete, E.; Rodríguez, D.; Ruz-Mieres, D.; Moya, A.; Sabatini-Gacitúa, L.; Sepúlveda-Cobo, C.; Camacho-Iñiguez, E.
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    An automated tool to detect variable sources in the vista variables in the ví­a láctea survey : the VVV variables (V4) catalog of tiles d001 and d002
    (2018) Medina, N.; Borissova, J.; Bayo, A.; Kurtev, R.; Navarro Molina, C.; Kuhn, M.; Kumar, N.; Lucas, P.W.; Catelan, Márcio; Minniti, D.; Smith, L. C.
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    Chemical abundances in giant stars of newly discovered infrared globular clusters 2MASS GC02 and Mercer 5
    (Asociación Argentina de Astronomía, 2011) Peñaloza, F.; Vásquez, S.; Kurtev, R.; Borissova, J.; Pessev, P.; Zoccali, Manuela
    Presentamos un estudio de abundacias de dos cúmulos globulares escondidos, Mercer5 y 2MASSGC02, utilizando espectros (IR) de alta resolución. Medimos precisas velocidades radiales de vr = +194 ± 0.3kms−1 para Mercer5 estrella 1 y vr = +177 ± 0.3kms−1 para Mercer5 estrella 2. Encontramos [Fe/H] = −1.00 ± 0.02dex y un realce en el promedio de α −elementos de ≈ +0.40 ± 0.02dex para Mercer5, mientras que para 2MASS GC02 sólo hacemos un análisis cualitativo, debido a su insuficiente señal/ruido.
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    Discovery of a brown dwarf companion to the A3V star beta Circini
    (2015) Smith, L.; Lucas, P.; Pena, C.; Kurtev, R.; Marocco, F.; Jones, H.; Beamin Muhlenbrock, Juan Carlos; Napiwotzki, R.; Borissova, J.; Burningham, B.; Faherty, J.; Pinfield, D.; Gromadzki, M.; Ivanov, V.; Minniti, D.; Stimson, W.; Villanueva, V.
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    Discovery of a variable star population in NGC 2808 (Corrigendum)
    (2012) Corwin, T. Michael; Catelan, Márcio; Borissova, J.; Smith, H. A.
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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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    Estudio infrarrojo de cúmulos inmersos en l = 345°
    (2011) Baume, G.; Feinstein, C.; Borissova, J.; Kurtev, R.; Chené, A. -N.; Moni Bidin, C.; Mauro, F.; Bonatto, C.; Bica, E.; Clarke, J. R. A.; Catelan, Márcio; Geisler, D.; Minniti, D.; Lucas, P. W.
    We have studied several embedded star clusters located in the fourth quad- rant of the Galactic plane (l 345 ; b +1.5 ). Data involves photometry and infrared spectroscopy (bands JHK and low dispersion respectively). This analysis has yielded a preliminary estimate of the fundamental param- eters of these objects and the behavior of the interstellar medium in this Galactic direction. FULL TEXT IN SPANISH...
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    FSR 1716: A New Milky Way Globular Cluster Confirmed Using VVV RR Lyrae Stars
    (2017) Hempel, Maren; Catelan, Márcio; Carballo Bello, J. A.; Ramos, R. C.; Gran, F.; Hagdu, G.; Navarrete, C.; Zoccali, Manuela; Minniti, D.; Palma, T.; Dekany, Istvan; Rejkuba, M.; Pullen, J.; Alonso Garcia, J.; Barba, R.; Barbuy, B.; Bica, E.; Borissova, J.; Chene, A. N.; Claria, J. J.; Cohen, R. E.; Dias, B.; Emerson, J.
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    Infrared photometry and CaT spectroscopy of globular cluster M 28 (NGC 6626)
    (2021) Moni Bidin, C.; Mauro, F.; Contreras Ramos, R.; Zoccali, M.; Reinarz, Y.; Moyano, M.; Gonzalez-Diaz, D.; Villanova, S.; Carraro, G.; Borissova, J.; Chene, A-N; Cohen, R. E.; Geisler, D.; Kurtev, R.; Minniti, D.
    Context. Recent studies show that the inner Galactic regions host genuine bulge globular clusters, but also halo intruders, complex remnants of primordial building blocks, and objects likely accreted during major merging events.Aims. In this study we focus on the properties of M 28, a very old and massive cluster currently located in the Galactic bulge.Methods. We analysed wide-field infrared photometry collected by the VVV survey, VVV proper motions, and intermediate-resolution spectra in the calcium triplet range for 113 targets in the cluster area.Results. Our results in general confirm previous estimates of the cluster properties available in the literature. We find no evidence of differences in metallicity between cluster stars, setting an upper limit of
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    Investigando cúmulos estelares masivos con el VVV
    (2011) Chené, A. -N.; Clarke, J. R. A.; Borissova, J.; Moni Bidin, C.; Mauro, F.; Bonatto, C.; Kurtev, R.; Baume, G.; Feinstein, C.; Minniti, D.; Catelan, Márcio; Lucas, P. W.; Geisler, D.
    Preliminary results are presented for the study of infrared data of three mas- sive stellar clusters. Have been combined photometric observations (JHK; VVV project = Vista Variables in the Vía Láctea) and spectroscopic (follow- up) observations of the brightest stars in these clusters. In this way we have been able to refine the values of distance, reddening, age and masses of the involved objects. FULL TEXT IN SPANISH...
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    Investigating potential planetary nebula/cluster pairs
    (2014) Moni Bidin, C.; Majaess, D.; Bonatto, C.; Mauro, F.; Turner, D.; Gieren Waiblinger, Wolfgang Paul; Chené, A.N.; Gormaz-Matamala, A.C.; Borissova, J.; Minniti, D.; Kurtev, R.G.; Carraro, G.; Gieren Waiblinger, Wolfgang Paul; Moni Bidin, C.; Majaess, D.; Bonatto, C.; Mauro, F.; Turner, D.; Geisler, D.; Chené, A.N.; Gormaz-Matamala, A.C.; Borissova, J.; Minniti, D.; Kurtev, R.G.; Carraro, G.; Gieren Waiblinger, Wolfgang Paul
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    Large-amplitude periodic outbursts and long-period variables in the VVV VIRAC2-β data base
    (2022) Guo, Zhen; Lucas, P. W.; Smith, L. C.; Clarke, C.; Contreras Peña, C.; Bayo, A.; Briceño, C.; Elias, J.; Kurtev, R. G.; Borissova, J.; Alonso-García, J.; Minniti, D.; Catelan, Márcio; Nikzat, F.; Morris, C.; Miller, N.
    The VISTA Variables in the Via Lactea (VVV) survey obtained near-infrared photometry towards the Galactic bulge and the southern disc plane for a decade (2010-2019). We designed a modified Lomb-Scargle method to search for large-amplitude ($\Delta K_{s, 2-98{{\ \rm per\ cent}}}$ > 1.5 mag) mid to long-term periodic variables (P> 10 d) in the 2nd version of VVV Infrared Astrometric Catalogue (VIRAC2-β). In total, 1520 periodic sources were discovered, including 59 candidate periodic outbursting young stellar objects (YSOs), based on the unique morphology of the phase-folded light curves, proximity to Galactic H II regions and mid-infrared colours. Five sources are spectroscopically confirmed as accreting YSOs. Both fast-rise/slow-decay and slow-rise/fast-decay periodic outbursts were found, but fast-rise/slow-decay outbursts predominate at the highest amplitudes. The multiwavelength colour variations are consistent with a variable mass accretion process, as opposed to variable extinction. The cycles are likely to be caused by dynamical perturbations from stellar or planetary companions within the circumstellar disc. An additional search for periodic variability amongst YSO candidates in published Spitzer-based catalogues yielded a further 71 candidate periodic accretors, mostly with lower amplitudes. These resemble cases of pulsed accretion but with unusually long periods and greater regularity. The majority of other long-period variables are pulsating dusty Miras with smooth and symmetric light curves. We find that some Miras have redder W3 - W4 colours than previously thought, most likely due to their surface chemical compositions....