Browsing by Author "Lucas, Philip W."

Now showing items 1-19 of 19

    • AGN candidates in the VVV near-IR galaxy catalogue 

      Baravalle, Laura D.; Schmidt, Eduardo O.; Alonso, M. Victoria; Pichel, Ana; Minniti, Dante; Rodríguez-Kamenetzky, Adriana R.; Masetti, Nicola; Villalon, Carolina; Smith, Leigh C.; Lucas, Philip W. (2023-04-30)
      The goal of this work is to search for Active Galactic Nuclei (AGN) in the Galactic disc at very low latitudes with |b|< 2°. For this, we studied the five sources from the VVV near-infrared (IR) galaxy catalogue that have ...

    • 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 ...

    • An Automated tool to detect variable sources in the Vista Variables in the Vía Láctea Survey. The VVV Variables (V^4) catalog of tiles d001 and d002 

      Medina, Nicolás; Borissova, Jura; Bayo, Amelia; Kurtev, Radostin; Navarro-Molina, Claudio; Kuhn, Michael; Kumar, Nanda; Lucas, Philip W.; Catelan, Márcio; Minniti, Dante; Smith, Leigh C. (2018-08-24)
      Time-varying phenomena are one of the most substantial sources of astrophysical information, and their study has led to many fundamental discoveries in modern astronomy. We have developed an automated tool to search for ...

    • 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 ...

    • Discovery of a new nearby globular cluster with extreme kinematics located in the extension of a halo stream 

      Minniti, Dante; Fernández-Trincado, José G.; Gómez, Matías; Smith, Leigh C.; Lucas, Philip W.; Ramos, R. Contreras (2021-06-01)
      Context. We report the discovery of VVV-CL160, a new nearby globular cluster (GC) with extreme kinematics, located in the Galactic plane at l = 10.1477 deg, b = 0.2999 deg. Aims. We aim to characterize the physical properties ...

    • 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 ...

    • Gaia21bty: An EXor light curve exhibiting a FUor spectrum 

      Siwak, Michał; Hillenbrand, Lynne A.; Kóspál, Ágnes; Ábrahám, Péter; Giannini, Teresa; De, Kishalay; Moór, Attila; Szilágyi, Máté; Janík, Jan; Koen, Chris; Park, Sunkyung; Nagy, Zsófia; Miera, Fernando Cruz-Sáenz de; Fiorellino, Eleonora; Marton, Gábor; Kun, Mária; Lucas, Philip W.; Udalski, Andrzej; Szabó, Zsófia Marianna (2023-10-30)
      Gaia21bty, a pre-main sequence star that previously had shown aperiodic dips in its light curve, underwent a considerable Delta G~2.9 mag brightening that occurred over a few months between 2020 October - 2021 February. ...

    • 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 ...

    • Mira variables in the Milky Way’s nuclear stellar disc: discovery and classification 

      Sanders, Jason L.; Matsunaga, Noriyuki; Kawata, Daisuke; Smith, Leigh C.; Minniti, Dante; Lucas, Philip W. (2022-11-30)
      The properties of the Milky Way's nuclear stellar disc give crucial information on the epoch of bar formation. Mira variables are promising bright candidates to study the nuclear stellar disc, and through their period-age ...

    • On the incidence of episodic accretion in Class I YSOs from VVV 

      Peña, Carlos Contreras; Lucas, Philip W.; Guo, Zhen; Smith, Leigh (2024-02-01)
      Episodic accretion is one of the competing models to explain the observed luminosity spread in young stellar clusters. These short-lived high accretion events could also have a strong impact on planet formation. Observations ...

    • Ongoing astrometric microlensing events from VVV and Gaia 

      McGill, Peter; Smith, Leigh C.; Evans, N. Wyn; Belokurov, Vasily; Lucas, Philip W. (2019-07)
      We extend predictive microlensing event searches using the Vista Variables in the Via Lactea survey and the second Gaia data release. We identify two events with maxima in 2019 that require urgent follow-up. First, we ...

    • 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 Survey Microlensing : Catalog of Best and Forsaken Events 

      Navarro, Maria Gabriela; Ramos, Rodrigo Contreras; Minniti, Dante; Pullen, Joyce; Capuzzo-Dolcetta, Roberto; Lucas, Philip W. (2020-04-10)
      We search for microlensing events in the zero-latitude area of the Galactic Bulge using the VVV Survey near-IR data. We have discovered a total sample of N = 630 events within an area covering 20.68 deg 2 between the years ...

    • 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?) ...