Browsing Research publications by Author "Lucas, P. W."

Now showing items 1-20 of 35

    • Analysis of physical processes in eruptive YSOs with near infrared spectra and multi-wavelength light curves 

      Guo, Zhen; Lucas, P. W.; Contreras Pena, Carlos; Smith, L. C.; Morris, C.; Kurtev, R. G.; Borissova, J.; Alonso-García, J.; Minniti, D.; Chené, A. -N.; Kumar, M. S. N.; Garatti, A. Caratti o; Froebrich, D. (2021-03-26)
      The decade-long Vista Variables in the Via Lactea (VVV) survey has detected numerous highly variable young stellar objects (YSOs). We present a study of 61 highly variable VVV YSOs (Delta Ks = 1-5 mag), combining near ...

    • Discovery of a mid-infrared protostellar outburst of exceptional amplitude 

      Lucas, P. W.; Elias, Jay; Points, Sean; Guo, Z.; Stecklum, B.; Vorobyov, E.; Morris, C.; Borissova, J.; Kurtev, R.; Pena, C. Contreras; Medina, N.; Minniti, D.; Ivanov, V. D.; Saito, R. K. (2020-09-23)
      We report the discovery of a mid-infrared outburst in a Young Stellar Object (YSO) with an amplitude close to 8 mag at lambda ~ 4.6 microns. WISEA J142238.82-611553.7 is one of 23 highly variable WISE sources discovered ...

    • Discovery of new globular clusters in the Sagittarius dwarf galaxy 

      Minniti, D.; Ripepi, V.; Fernández-Trincado, J. G.; Alonso-García, J.; Smith, L. C.; Lucas, P. W.; Gómez, M.; Pullen, J. B.; Garro, E. R.; Cádiz, F. Vivanco; Hempel, M.; Rejkuba, M.; Saito, R. K.; Palma, T.; Clariá, J. J.; Gregg, M.; Majaess, D. (2021-03-12)
      Context. Globular clusters (GCs) are witnesses of the past accretion events onto the Milky Way. In particular, the GCs of the Sagittarius (Sgr) dwarf galaxy are important probes of an on-going merger. Aims. Our main goal ...

    • Evidence of distant spiral arms in the Galactic disk quadrant IV from VVV red clump giants 

      Kammers, R.; Saito, R. K.; Botan, E.; Minniti, D.; Alonso-García, J.; Smith, L. C.; Lucas, P. W. (2022-09-09)
      The discovery of new clear windows in the Galactic plane using the VVV near-IR extinction maps allows the study of the structure of the Milky Way (MW) disk. The ultimate goal of this work is to map the spiral arms in the ...

    • Extreme infrared variables from UKIDSS - II. an end-of-survey catalogue of eruptive YSOs and unusual stars 

      Lucas, P. W.; Smith, L. C.; Pena, C. Contreras; Froebrich, Dirk D.; Drew, Janet E.; Kumar, M. S. N.; Borissova, J.; Minniti, D.; Kurtev, R.; Monguio, M. (2017-12-11)
      We present a catalogue of 618 high-amplitude infrared variable stars (1 < ΔK < 5 mag) detected by the two widely separated epochs of 2.2 μm data in the UKIDSS Galactic plane survey, from searches covering ∼1470 deg2. Most ...

    • Highly variable young massive stars in ATLASGAL clumps 

      Kumar, M. S. N.; Contreras-Pena, C.; Lucas, P. W.; Thompson, M. A. (2016-12-05)
      High-amplitude variability in Young Stellar Objects (YSOs) is usually associated with episodic accretion events. It has not been observed so far in massive YSOs. Here, the high-amplitude variable star sample of ContrerasPena ...

    • Infrared spectroscopy of eruptive variable protostars from VVV 

      Peña, C. Contreras; Lucas, P. W.; Kurtev, R.; Minniti, D.; Garatti, A. Caratti o; Marocco, F.; Thompson, M. A.; Froebrich, D.; Kumar, N.; Stimson, W.; Molina, C. Navarro; Borissova, J.; Gledhill, T.; Terzi, R. (2017-03-01)
      In a companion work (Paper I) we detected a large population of highly variable Young Stellar Objects (YSOs) in the Vista Variables in the Via Lactea (VVV) survey, typically with class I or flat spectrum spectral energy ...

    • Large amplitude periodic outbursts and long period variables in the VVV VIRAC2-$β$ database 

      Guo, Zhen; Lucas, P. W.; Smith, L. C.; Clarke, C.; Peña, C. Contreras; Bayo, A.; Briceño, C.; Elias, J.; Kurtev, R. G.; Borissova, J.; Alonso-García, J.; Minniti, D.; Catelan, M.; Nikzat, F.; Morris, C.; Miller, N. (2022-03-21)
      The VISTA Variables in the Via Lactea (VVV) survey obtained near-infrared photometry toward the Galactic bulge and the southern disc plane for a decade (2010 - 2019). We designed a modified Lomb-Scargle method to search ...

    • Long-term Stellar Variability in the Galactic Centre Region 

      Molina, C. Navarro; Borissova, J.; Catelan, M.; Lucas, P. W.; Medina, N.; Pena, C. Contreras; Kurtev, R.; Minniti, D. (2019-02)
      We report the detection of variable stars within a 11.5' x 11.5' region near the Galactic centre (GC) that includes the Arches and Quintuplet clusters, as revealed by the VISTA Variables in the Via Lactea (VVV) survey. ...

    • Mapping the stellar age of the Milky Way bulge with the VVV : II. Deep JK s catalog release based on PSF photometry 

      Surot, F.; Valenti, Elena; Hidalgo, S. L.; Zoccali, M.; Gonzalez, O. A.; Sökmen, E.; Minniti, D.; Rejkuba, M.; Lucas, P. W. (2019-09-01)
      Context. The bulge represents the best compromise between old and massive Galactic components, and as such its study is a valuable opportunity to understand how the bulk of the Milky Way formed and evolved. In addition, ...

    • The most variable VVV sources: eruptive protostars, dipping giants in the Nuclear Disc and others 

      Lucas, P. W.; Smith, L. C.; Guo, Z.; Peña, C. Contreras; Minniti, D.; Miller, N.; Alonso-García, Javier; Catelan, M.; Borissova, J.; Saito, R. K.; Kurtev, R.; Navarro, M. G.; Morris, C.; Muthu, H.; Froebrich, D.; Ivanov, V. D.; Bayo, A.; Garatti, A. Caratti o; Sanders, J. L. (2024-02-01)
      We have performed a comprehensive search of a VISTA Variables in the Via Lactea (VVV) data base of 9.5 yr light curves for variable sources with ΔKs ≥ 4 mag, aiming to provide a large sample of high amplitude eruptive young ...

    • Multiwavelength detection of an ongoing FUOr-type outburst on a low-mass YSO 

      Guo, Zhen; Lucas, P. W.; Kurtev, R. G.; Borissova, J.; Elbakyan, V.; Morris, C.; Bayo, A.; Smith, L.; Garatti, A. Caratti o; Peña, C. Contreras; Minniti, D.; Jose, J.; Ashraf, M.; Alonso-García, J; Miller, N.; Muthu, H. D. S. (2024-03-01)
      During the pre-main-sequence evolution, Young Stellar Objects (YSOs) assemble most of their mass during the episodic accretion process. The rarely seen FUOr-type events are valuable laboratories to investigate the outbursting ...

    • Near-infrared photometry and spectroscopy of the low Galactic latitude globular cluster 2MASS-GC03 

      Carballo-Bello, Julio A.; Alegria, S. Ramirez; Borissova, J.; Smith, L. C.; Kurtev, R.; Lucas, P. W.; Bidin, Ch Moni; Alonso-Garcia, J.; Minniti, D.; Palma, T.; Dekany, I.; Medina, N.; Moyano, M.; Villanueva, V.; Kuhn, M. A. (2016-10-11)
      We present deep near-infrared photometry and spectroscopy of the globular cluster 2MASS-GC03 projected in the Galactic disk using MMIRS on the Clay telescope (Las Campanas Observatory) and VISTA Variables in the Via Lactea ...

    • New Eruptive YSOs from SPICY and WISE 

      Peña, Carlos Contreras; Ashraf, M.; Lee, J. E.; Herczeg, G.; Lucas, P. W.; Guo, Z.; Johnstone, D.; Lee, H. G.; Jose, J. (2023-12-28)
      This work presents four high-amplitude variable YSOs (≃3 mag at near-or mid-IR wavelengths) arising from the SPICY catalog. Three outbursts show a duration that is longer than 1 year, and are still ongoing. And additional ...

    • New Galactic star clusters discovered in the disc area of the VVVX survey 

      Borissova, J.; Ivanov, V. D.; Lucas, P. W.; Kurtev, R.; Alonso-Garcia, J.; Alegria, S. Ramirez; Minniti, D.; Hempel, M.; Medina, N.; Chene, A. N.; Kuhn, M. A. (2018-12-11)
      The "VISTA Variables in the Via Lactea eXtended (VVVX)" ESO Public Survey is a near-infrared photometric sky survey that covers nearly 1700 sq. deg towards the Galactic disk and bulge. It is well-suited to search for new ...

    • Photometric variability of massive young stellar objects 

      Teixeira, G. D. C.; Kumar, M. S. N.; Smith, L.; Lucas, P. W.; Morris, C.; Borissova, J.; Monteiro, M. J. P. F. G.; Garatti, A. Caratti o; Peña, C. Contreras; Froebrich, Dirk; Gameiro, J. F. (2018-11-05)
      The Vista Variables in the Via Lactea (VVV) survey has allowed for an unprecedented number of multi-epoch observations of the southern Galactic plane. In a recent paper, 13 massive young stellar objects (MYSOs) have already ...

    • The polarisation of HD 189733 

      Bott, Kimberly; Bailey, Jeremy; Kedziora-Chudczer, Lucyna; Cotton, Daniel V.; Lucas, P. W.; Marshall, Jonathan P.; Hough, J. H. (2016-06-11)
      We present linear polarization observations of the exoplanet system HD 189733 made with the HIgh Precision Polarimetric Instrument (HIPPI) on the Anglo-Australian Telescope (AAT). The observations have higher precision ...

    • Polarization due to rotational distortion in the bright star Regulus 

      Cotton, Daniel V.; Bailey, Jeremy A.; Howarth, Ian D.; Bott, Kimberly; Kedziora-Chudczer, Lucyna; Lucas, P. W.; Hough, J. H. (2018-10-01)
      Polarization in stars was first predicted by Chandrasekhar [1] who calculated a substantial linear polarization at the stellar limb for a pure electron-scattering atmosphere. This polarization will average to zero when ...

    • Polarization of hot Jupiter systems: a likely detection of stellar activity and a possible detection of planetary polarization 

      Bailey, Jeremy; Bott, Kimberly; Cotton, Daniel V.; Kedziora-Chudczer, Lucyna; Zhao, Jinglin; Evensberget, Dag; Marshall, Jonathan P.; Wright, Duncan; Lucas, P. W. (2021-04-01)
      We present high-precision linear polarization observations of four bright hot Jupiter systems ($\tau$ Boo, HD 179949, HD 189733 and 51 Peg) and use the data to search for polarized reflected light from the planets. The ...

    • A population of eruptive variable protostars in VVV 

      Peña, C. Contreras; Lucas, P. W.; Minniti, D.; Kurtev, R.; Stimson, W.; Molina, C. Navarro; Borissova, J.; Kumar, N.; Thompson, M. A.; Gledhill, T.; Terzi, R.; Froebrich, D.; Garatti, A. Caratti o (2017-03-01)
      We present the discovery of 816 high amplitude infrared variable stars (Delta Ks >1 mag) in 119 deg^2 of the Galactic midplane covered by the Vista Variables in the Via Lactea (VVV) survey. Almost all are new discoveries ...