Browsing University of Hertfordshire by Author "Clarke, J. R. A."

Now showing items 1-13 of 13

    • 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 ...

    • Blue not brown: UKIRT Infrared Deep Sky Survey T dwarfs with suppressed K-band flux 

      Murray, D. N.; Burningham, B.; Jones, H.R.A.; Pinfield, D.J.; Lucas, P.W.; Leggett, S. K.; Tinney, C. G.; Day-Jones, A. C.; Weights, D. J.; Lodieu, N.; Perez Prieto, J. A.; Nickson, E.; Zhang, Z. H.; Clarke, J. R. A.; Jenkins, J. S.; Tamura, M. (2011-06)
      We have used blue near-infrared colours to select a group of 12 spectroscopically confirmed United Kingdom InfraRed Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS) T dwarfs later than T4. From amongst these, we identify ...

    • 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 ...

    • Discovery of a new Y dwarf: WISE J030449.03-270508.3 

      Pinfield, D.J.; Gromadzki, M.; Leggett, S.K.; Gomes, J.; Lodieu, N.; Kurtev, R.; Day-Jones, A. C.; Ruiz, M. T.; Cook, N. J.; Morley, C.V.; Marley, M. S.; Marocco, F.; Smart, R.L.; Jones, H.R.A.; Lucas, P.W.; Beletsky, Y.; Ivanov, V. D.; Burningham, B.; Jenkins, J. S.; Cardoso, C.; Frith, J.; Clarke, J. R. A.; Gálvez-Ortiz, M. C.; Zhang, Z. (2014-10-21)
      We present a new Y dwarf, WISE J030449.03−270508.3, confirmed from a candidate sample designed to pick out low-temperature objects from the Wide-field Infrared Survey Explorer (WISE) data base. The new object is typed Y0pec ...

    • 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 ...

    • New Galactic star clusters discovered in the VVV survey 

      Borissova, J.; Bonatto, C.; Kurtev, R.; Clarke, J. R. A.; Penaloza, F.; Sale, S. E.; Minniti, D.; Alonso-Garcia, J.; Artigau, E.; Barba, R.; Bica, E.; Baume, G. L.; Catelan, M.; Chene, A. N.; Dias, B.; Folkes, S. L.; Froebrich, D.; Geisler, D.; de Grijs, R.; Hanson, M. M.; Hempel, M.; Ivanov, V. D.; Kumar, M. S. N.; Lucas, P.W.; Mauro, F.; Moni Bidin, C.; Rejkuba, M.; Saito, R. K.; Tamura, M.; Toledo, I. (2011-08)
      Context. VISTA Variables in the Via Lactea (VVV) is one of the six ESO Public Surveys operating on the new 4-m Visible and Infrared Survey Telescope for Astronomy (VISTA). VVV is scanning the Milky Way bulge and an adjacent ...

    • New galactic star clusters discovered in the VVV survey : Candidates projected on the inner disk and bulge 

      Borissova, J.; Chené, A. N.; Ramírez Alegría, S.; Sharma, S.; Clarke, J. R. A.; Kurtev, R.; Negueruela, I.; Marco, A.; Amigo, P.; Minniti, D.; Bica, E.; Bonatto, C.; Catelan, M.; Fierro, C.; Geisler, D.; Gromadzki, M.; Hempel, M.; Hanson, M. M.; Ivanov, V. D.; Lucas, P.W.; Majaess, D.; Moni Bidin, C.; Popescu, B.; Saito, R.K. (2014-09)
      Context. VISTA Variables in the Vía Láctea (VVV) is one of six ESO Public Surveys using the 4 meter Visible and Infrared Survey Telescope for Astronomy (VISTA). The VVV survey covers the Milky Way bulge and an adjacent ...

    • Parallaxes of Five L Dwarfs with a Robotic Telescope 

      Wang, Y.; Jones, H.R.A.; Smart, R.L.; Marocco, F.; Pinfield, D.J.; Shao, Z.; Steele, I.A.; Zhang, Z.; Andrei, A.H.; Burgasser, A. J.; Cruz, K. L.; Yu, J.; Clarke, J. R. A.; Leigh, C.J.; Sozzetti, A.; Murray, D. N.; Burningham, B. (2014-01-01)
      We report the parallax and proper motion of five L dwarfs obtained with observations from the robotic Liverpool Telescope. Our derived proper motions are consistent with published values and have considerably smaller errors. ...

    • Parallaxes of southern extremely cool objects (PARSEC). II : Spectroscopic follow-up and parallaxes of 52 targets 

      Marocco, F.; Andrei, A.H.; Smart, R.L.; Jones, H.R.A.; Pinfield, D.J.; Day-Jones, A. C.; Clarke, J. R. A.; Sozzetti, A.; Lucas, P.W.; Bucciarelli, B.; Penna, J.L. (2013-12)
      We present near-infrared spectroscopy for 52 ultracool dwarfs, including two newly discovered late-M dwarfs, one new late-M subdwarf candidate, three new L, and four new T dwarfs. We also present parallaxes and proper ...

    • 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 ...

    • The sub-stellar birth rate from UKIDSS 

      Day-Jones, A. C.; Marocco, F.; Pinfield, D.J.; Zhang, Z. H.; Burningham, B.; Deacon, Niall; Ruiz, M. T.; Gallardo, J.; Jones, H.R.A.; Lucas, P.W.; Jenkins, J. S.; Gomes, J.; Folkes, S. L.; Clarke, J. R. A. (2013-04)
      We present a new sample of mid-L to mid-T dwarfs with effective temperatures of 11001700 K selected from the UKIDSS Large Area Survey (LAS) and confirmed with infrared spectra from X-shooter/Very Large Telescope. This ...