Browsing University of Hertfordshire by Author "Galvez-Ortiz, M. C."

Now showing items 1-14 of 14

    • Benchmark low-mass objects in Moving Groups 

      Galvez-Ortiz, M. C.; Kuznetsov, M.; Clarke, J. R. A.; Pavlenko, Ya. V.; Pinfield, D.J.; Jones, H.R.A.; Jenkins, J. S.; Barnes, J.; Burningham, B.; Day-Jones, A. C.; Martin, E. L.; Perez, A. E. Garcia; Pokorny, R.S. (EDP Sciences, 2013)
      In order to compile a sample of ultracool dwarfs that will serve as benchmarks for testing theoretical formation and evolutionary models, we selected low-mass cool (>M7) objects that are potentially members of five known ...

    • A deep WISE search for very late type objects and the discovery of two halo/thick-disc T dwarfs : WISE 0013+0634 and WISE 0833+0052 

      Pinfield, D.J.; Gomes, J.; Day-Jones, A. C.; Leggett, S.K.; Gromadzki, M.; Burningham, B.; Ruiz, M. T.; Kurtev, R.; Cattermole, T.; Cardoso, C.; Lodieu, N.; Faherty, J.; Littlefair, S.; Smart, R.; Irwin, M.; Clarke, J. R. A.; Smith, Leigh; Lucas, P.W.; Galvez-Ortiz, M. C.; Jenkins, J. S.; Jones, H.R.A.; Rebolo, R.; Bejar, V. J. S.; Gauza, B. (2014-01-11)
      A method is defined for identifying late-T and Y dwarfs in WISE down to low values of signal-to-noise. This requires a WISE detection only in the W2-band and uses the statistical properties of the WISE multiframe measurements ...

    • The first planet detected in the WTS : an inflated hot-Jupiter in a 3.35 day orbit around a late F-star [ERRATUM] 

      Cappetta, M.; Saglia, R.P.; Birkby, J. L.; Koppenhoefer, J.; Pinfield, D.J.; Hodgkin, S.T.; Cruz, P.; Kovacs, G.; Sipocz, B.; Barrado, D.; Nefs, B.; Pavlenko, Y. V.; Fossati, L.; Burgo, C. del; Martin, E. L.; Snellen, I.; Barnes, J.; Campbell, D. A.; Catalan, S.; Galvez-Ortiz, M. C.; Goulding, N.; Haswell, C.; Ivanyuk, O.; Jones, H.R.A.; Kuznetsov, M.; Lodieu, N.; Marocco, F.; Mislis, D.; Murgas, F.; Napiwotzki, R.; Palle, E.; Pollacco, D.; Baro, L. Sarro; Solano, E.; Steele, P.; Stoev, H.; Tata, R.; Zendejas, J. (2014-11-11)
      We report the discovery of WTS-1b, the first extrasolar planet found by the WFCAM Transit Survey, which began observations at the 3.8-m United Kingdom Infrared Telescope (UKIRT) in August 2007. Light curves comprising ...

    • FR Cnc revisited : photometry, polarimetry and spectroscopy 

      Golovin, A.; Galvez-Ortiz, M. C.; Hernan-Obispo, M.; Andreev, M.; Barnes, J. R.; Montes, D.; Pavlenko, E.; Pandey, J. C.; Martinez-Arnaiz, R.; Medhi, B. J.; Parihar, P. S.; Henden, A.; Sergeev, A.; Zaitsev, S. V.; Karpov, N. (2012-03)
      This paper is part of a multiwavelength study aimed at using complementary photometric, polarimetric and spectroscopic data to achieve an understanding of the activity process in late-type stars. Here, we present the study ...

    • Identifying ultra-cool dwarfs at low Galactic latitudes : a southern candidate catalogue 

      Folkes, S. L.; Pinfield, D.J.; Jones, H.R.A.; Kurtev, R.; Zhang, Z.; Galvez-Ortiz, M. C.; Marocco, F.; Day-Jones, A. C.; Clarke, J. R. A. (2012-12)
      We present an ultra-cool dwarf (UCD) catalogue compiled from low southern Galactic latitudes and mid-plane, from a cross-correlation of the Two Micron All-Sky Survey (2MASS) and the SuperCOSMOS survey. The catalogue contains ...

    • Low-mass Objects in Moving Groups 

      Galvez-Ortiz, M. C.; Clarke, J. R. A.; Pinfield, D.J.; Folkes, S. L.; Jenkins, J. S.; Perez, A. E. Garcia; Burningham, B.; Day-Jones, A. C.; Jones, H.R.A. (Astronomical Society of the Pacific, 2010)
      We present here the kinematic study of part of a 132 target sample of low-mass objects, previously selected by photometric and astrometric criteria as possible members to five young moving groups (MGs): Local Association ...

    • Primeval very low-mass stars and brown dwarfs - III. The halo transitional brown dwarfs 

      Zhang, Z. H.; Pinfield, D. J.; Galvez-Ortiz, M. C.; Homeier, D.; Burgasser, A. J.; Lodieu, N.; Martin, E. L.; Osorio, M. R. Zapatero; Allard, F.; Jones, H. R. A.; Smart, R. L.; Marti, B. Lopez; Burningham, B.; Rebolo, R. (2018-09-01)
      We report the discovery of an esdL3 subdwarf, ULAS J020858.62+020657.0 and a usdL4.5 subdwarf, ULAS J230711.01+014447.1. They were identified as L subdwarfs by optical spectra obtained with the Gran Telescopio Canarias, ...

    • Primeval very low-mass stars and brown dwarfs - IV. New L subdwarfs, Gaia astrometry, population properties, and a blue brown dwarf binary 

      Zhang, Z. H.; Galvez-Ortiz, M. C.; Pinfield, D. J.; Burgasser, A. J.; Lodieu, N.; Jones, H. R. A.; Martin, E. L.; Burningham, B.; Homeier, D.; Allard, F.; Osorio, M. R. Zapatero; Smith, L. C.; Smart, R. L.; Marti, B. Lopez; Marocco, F.; Rebolo, R. (2018-11-11)
      We present 27 new L subdwarfs and classify five of them as esdL and 22 as sdL. Our L subdwarf candidates were selected with the UKIRT Infrared Deep Sky Survey and Sloan Digital Sky Survey. Spectroscopic follow-up was carried ...

    • Primeval very low-mass stars and brown dwarfs - VI. Population properties of metal-poor degenerate brown dwarfs 

      Zhang, Z. H.; Burgasser, A. J.; Galvez-Ortiz, M. C.; Lodieu, N.; Osorio, M. R. Zapatero; Pinfield, D. J.; Allard, F. (2019-06-01)
      We presented 15 new T dwarfs that were selected from UKIRT Infrared Deep Sky Survey, Visible and Infrared Survey Telescope for Astronomy, and Wide-field Infrared Survey Explorer surveys, and confirmed with optical to near ...

    • Primeval very low-mass stars and brown dwarfs. I. Six new L subdwarfs, classification and atmospheric properties 

      Zhang, Z. H.; Pinfield, D. J.; Galvez-Ortiz, M. C.; Burningham, B.; Lodieu, N.; Marocco, F.; Burgasser, A. J.; Day-Jones, A. C.; Allard, F.; Jones, H. R. A.; Homeier, D.; Gomes, J.; Smart, R. L. (2017-01-01)
      We have conducted a search for L subdwarf candidates within the photometric catalogues of the UKIRT Infrared Deep Sky Survey and Sloan Digital Sky Survey. Six of our candidates are confirmed as L subdwarfs spectroscopically ...

    • Purple dwarfs : New L subdwarfs from UKIDSS and SDSS 

      Zhang, Z. H.; Pinfield, D.J.; Burningham, B.; Jones, H.R.A.; Day-Jones, A. C.; Marocco, F.; Gomes, J.; Galvez-Ortiz, M. C. (EDP Sciences, 2013)
      The first L subdwarf was a discovered only ten years ago. Less than ten L subdwarfs been published in the literature to date. Metal-poor ultracool atmospheres has not been well understood. Halo mass function cross substellar ...

    • A spectroscopic and proper motion search of Sloan Digital Sky Survey : red subdwarfs in binary systems 

      Zhang, Z. H.; Pinfield, D.J.; Burningham, B.; Jones, H.R.A.; Galvez-Ortiz, M. C.; Catalan, S.; Smart, R. L.; Lepine, S.; Clarke, J. R. A.; Pavlenko, Ya V.; Murray, D. N.; Kuznetsov, M. K.; Day-Jones, A. C.; Gomes, J.; Marocco, F.; Sipocz, B. (2013-09)
      Red subdwarfs in binary systems are crucial for both model calibration and spectral classification. We search for red subdwarfs in binary systems from a sample of high proper motion objects with Sloan Digital Sky Survey ...

    • Spectroscopic signatures of youth in low-mass kinematic candidates of young moving groups 

      Galvez-Ortiz, M. C.; Kuznetsov, M.; Clarke, J. R. A.; Pavlenko, Ya. V.; Folkes, S. L.; Pinfield, David; Jones, Hugh; Jenkins, J. S.; Barnes, John; Burmingham, B.; Day-Jones, A. C.; Martin, E. L.; Garcia Perez, A. E.; del Burgo, C.; Pokorny, R. S. (2014-04-21)
      We present a study of age-related spectral signatures observed in 25 young low-mass objects that we have previously determined as possible kinematic members of five young moving groups: the Local Association (Pleiades ...

    • Spectroscopy and kinematics of low-mass members of young moving groups 

      Galvez-Ortiz, M. C.; Clarke, J.R.A.; Pinfield, D.J.; Jenkins, J. S.; Folkes, S. L.; Garcia Perez, A. E.; Day-Jones, A.C.; Burningham, B.; Jones, H.R.A.; Barnes, J. R.; Pokorny, R.S. (2010)
      We study a target sample of 68 low-mass objects (with spectral types in the range M4.5–L1) previously selected via photometric and astrometric criteria, as possible members of five young moving groups: the Local Association ...