Browsing by Author "Saito, Roberto K."

Now showing items 1-14 of 14

    • The asymptotic evolution of the stellar merger V1309 Sco: a Blue Straggler in the making? 

      Ferreira, Thiago; Saito, Roberto K.; Minniti, Dante; Navarro, María Gabriela; Ramos, Rodrigo Contreras; Smith, Leigh; Lucas, Philip W. (2019-06-01)
      Stellar mergers are estimated to be common events in the Galaxy. The best studied stellar merger case to date is V1309 Sco (= Nova Scorpii 2008) which was originally misclassified as a Nova event. Later identified as the ...

    • A Benchmark White Dwarf-Ultracool Dwarf Wide Field Binary 

      Ferreira, Thiago; Saito, Roberto K.; Minniti, Dante; Mejías, Andrea; Caceres, Claudio; Alonso-García, Javier; Beamín, Juan Carlos; Smith, Leigh C.; Gomez, Matías; Lucas, Philip W.; Ivanov, Valentin D. (2023-12-19)
      We present the discovery and multi-wavelength characterisation of VVV J1438-6158 AB, a new field wide-binary system consisting of a 4.6(+5.5-2.4) Gyr and Teff = 9500+/-125 K DA white dwarf (WD) and a Teff = 2400+/-50 K M8 ...

    • Characterization of the VVV Survey RR Lyrae Population across the Southern Galactic Plane 

      Minniti, Dante; Dékány, Istvan; Majaess, Daniel; Palma, Tali; Pullen, Joyce; Rejkuba, Marina; Alonso-García, Javier; Catelan, Marcio; Ramos, Rodrigo Contreras; Gonzalez, Oscar A.; Hempel, Maren; Irwin, Mike; Lucas, Philip W.; Saito, Roberto K.; Tissera, Patricia; Valenti, Elena; Zoccali, Manuela (2017-03-27)
      Deep near-IR images from the VISTA Variables in the Vía Láctea (VVV) Survey were used to search for RR Lyrae stars in the Southern Galactic plane. A sizable sample of 404 RR Lyrae of type ab stars was identified across a ...

    • The Emergence of the Infrared transient VVV-WIT-06 

      Minniti, Dante; Saito, Roberto K.; Forster, F.; Pignata, G.; Ivanov, Valentin D.; Lucas, Philip; Beamin, J.C.; Borissova, Jura; Catelan, Marcio; Gonzalez, Oscar A.; Hempel, Maren; Hsiao, E; Kurtev, Radostin; Majaess, Daniel; Masetti, N.; Morrell, N.I.; Phillips, M.M.; Pullen, J. B.; Rejkuba, M.; Smith, L.C.; Surot, F.; Valenti, Elena; Zoccali, Manuela (2017-11-03)
      We report the discovery of an enigmatic large-amplitude (ΔKs> 10.5 mag) transient event in near-IR data obtained by the VISTA Variables in the Via Lactea (VVV) ESO Public Survey. The object (designated VVV-WIT-06) is located ...

    • Extinction ratios in the inner Galaxy as revealed by the VVV survey 

      Alonso-García, Javier; Minniti, Dante; Catelan, Márcio; Ramos, Rodrigo Contreras; Gonzalez, Oscar A.; Hempel, Maren; Lucas, Philip W.; Saito, Roberto K.; Valenti, Elena; Zoccali, Manuela (2017-11-01)
      Interstellar extinction towards the Galactic Center is large and significantly differential. Its reddening and dimming effects in red clump stars in the Galactic Bulge can be exploited to better constrain the extinction ...

    • FSR 1716: A new Milky Way Globular Cluster confirmed using VVV RR Lyrae stars 

      Minniti, Dante; Palma, Tali; Dékány, Istvan; Hempel, Maren; Rejkuba, Marina; Pullen, Joyce; Alonso-García, Javier; Barbá, Rodolfo; Barbuy, Beatriz; Bica, Eduardo; Bonatto, Charles; Borissova, Jura; Catelan, Marcio; Carballo-Bello, Julio A.; Chene, Andre Nicolas; Clariá, Juan J.; Cohen, Roger E.; Contreras-Ramos, Rodrigo; Dias, Bruno; Emerson, Jim; Froebrich, Dirk; Buckner, Anne S. M.; Geisler, Douglas; Gonzalez, Oscar A.; Gran, Felipe; Hagdu, Gergely; Irwin, Mike; Ivanov, Valentin D.; Kurtev, Radostin; Lucas, Philip W.; Majaess, Daniel; Mauro, Francesco; Moni-Bidin, Christian; Navarrete, Camila; Alegría, Sebastian Ramírez; Saito, Roberto K.; Valenti, Elena; Zoccali, Manuela (2017-03-24)
      We use deep multi-epoch near-IR images of the VISTA Variables in the V\'ia L\'actea (VVV) Survey to search for RR Lyrae stars towards the Southern Galactic plane. Here we report the discovery of a group of RR Lyrae stars ...

    • The globular cluster VVV CL002 falling down to the hazardous Galactic centre 

      Minniti, Dante; Matsunaga, Noriyuki; Fernández-Trincado, José G.; Otsubo, Shogo; Sarugaku, Yuki; Takeuchi, Tomomi; Katoh, Haruki; Hamano, Satoshi; Ikeda, Yuji; Kawakita, Hideyo; Lucas, Philip W.; Smith, Leigh C.; Petralia, Ilaria; Rita Garro, Elisa; Saito, Roberto K.; Alonso-García, Javier; Gómez, Matías; Gabriela Navarro, María (2024-03-15)
      Context. The Galactic centre is hazardous for stellar clusters because of the strong tidal force in action there. It is believed that many clusters were destroyed there and contributed stars to the crowded stellar field ...

    • Milky Way demographics with the VVV survey. IV. PSF photometry from almost one billion stars in the Galactic bulge and adjacent southern disk 

      Alonso-García, Javier; Saito, Roberto K.; Hempel, Maren; Minniti, Dante; Pullen, Joyce; Catelan, Márcio; Ramos, Rodrigo Contreras; Cross, Nicholas J. G.; Gonzalez, Oscar A.; Lucas, Philip W.; Palma, Tali; Valenti, Elena; Zoccali, Manuela (2018-11-01)
      Context. The inner regions of the Galaxy are severely affected by extinction, which limits our capability to study the stellar populations present there. The Vista Variables in the Vía Láctea (VVV) ESO Public Survey has ...

    • A new near-IR window of low extinction in the Galactic plane 

      Minniti, Dante; Saito, Roberto K.; Gonzalez, Oscar A.; Alonso-García, Javier; Rejkuba, Marina; Barbá, Rodolfo; Irwin, Mike; Kammers, Roberto; Lucas, Philip; Majaess, Daniel; Valenti, Elena (2018-08-01)
      Aims. The windows of low extinction in the Milky Way (MW) plane are rare but important because they enable us to place structural constraints on the opposite side of the Galaxy, which has hither to been done rarely. Methods. ...

    • New VVV Survey Globular Cluster Candidates in the Milky Way Bulge 

      Minniti, Dante; Geisler, Douglas; Alonso-García, Javier; Palma, Tali; Beamin, Juan Carlos; Borissova, Jura; Catelan, Marcio; Clariá, Juan J.; Cohen, Roger E.; Ramos, Rodrigo Contreras; Dias, Bruno; Fernandez-Trincado, Jose; Gomez, Matias; Hempel, Maren; Ivanov, Valentin D.; Kurtev, Radostin; Lucas, Philip; Moni-Bidin, Christian; Pullen, Joyce; Alegría, Sebastian Ramírez; Saito, Roberto K.; Valenti, Elena (2017-11-10)
      It is likely that a number of Galactic globular clusters remain to be discovered, especially toward the Galactic bulge. High stellar density combined with high and differential interstellar reddening are the two major ...

    • Variable stars in the VVV globular clusters. II. NGC6441, NGC6569, NGC6626 (M28), NGC6656 (M22), 2MASS-GC02, and Terzan10 

      Alonso-García, Javier; Smith, Leigh C.; Catelan, Márcio; Minniti, Dante; Navarrete, Camila; Borissova, Jura; Carballo-Bello, Julio A.; Ramos, Rodrigo Contreras; Fernández-Trincado, José G.; Lopes, Carlos E. Ferreira; Gran, Felipe; Garro, Elisa R.; Geisler, Doug; Guo, Zhen; Hempel, Maren; Kerins, Eamonn; Lucas, Philip W.; Palma, Tali; Ramírez, Karla Peña; Alegría, Sebastián Ramírez; Saito, Roberto K. (2021-07-12)
      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 ...

    • VVV-WIT-04: an extragalactic variable source caught by the VVV Survey 

      Saito, Roberto K.; Minniti, Dante; Ivanov, Valentin D.; Masetti, Nicola; Navarro, Maria Gabriela; Fernandes, Roberto Cid; Ruschel-Dutra, Daniel; Smith, Leigh C.; Lucas, Philip W.; Gonzalez-Fernandez, Carlos; Ramos, Rodrigo Contreras (2019-09-20)
      We report the discovery of VVV-WIT-04, a near-infrared (near-IR) variable source towards the Galactic disc located ∼0.2 arcsec apart from the position of the radio source PMN J1515−5559. The object was found serendipitously ...

    • VVV-WIT-08: the giant star that blinked 

      Smith, Leigh C.; Koposov, Sergey E.; Lucas, Philip W.; Sanders, Jason L.; Minniti, Dante; Udalski, Andrzej; Evans, N. Wyn; Aguado, David; Ivanov, Valentin D.; Saito, Roberto K.; Fraga, Luciano; Pietrukowicz, Pawel; Penoyre, Zephyr; González-Fernández, Carlos (2021-06-11)
      We report the serendipitous discovery of a late-type giant star that exhibited a smooth, eclipse-like drop in flux to a depth of 97 per cent. Minimum flux occurred in April 2012 and the total event duration was a few hundred ...

    • VVV-WIT-12 and Its Fashionable Nebula: A 4 yr Long-period Young Stellar Object with a Light Echo? 

      Saito, Roberto K.; Stecklum, Bringfried; Minniti, Dante; Lucas, Philip W.; Guo, Zhen; Smith, Leigh C.; Fraga, Luciano; Navarete, Felipe; Beamin, Juan Carlos; Morris, Calum (2023-11-14)
      We report the serendipitous discovery of VVV-WIT-12, an unusual variable source that seems to induce variability in its surrounding nebula. The source belongs to the rare objects that we call WITs (short for What Is This?) ...