Browsing Research publications by Author "Day-Jones, A. C."

Now showing items 1-20 of 20

    • 76 T dwarfs from the UKIDSS LAS : benchmarks, kinematics and an updated space density 

      Burningham, B.; Cardoso, C. V.; Smith, Leigh; Leggett, S.K.; Smart, R.L.; Mann, A. W.; Dhital, S.; Lucas, P.W.; Tinney, C.G.; Pinfield, D.J.; Zhang, Z.; Morley, C.; Saumon, D.; Aller, K.; Littlefair, S. P.; Homeier, D.; Lodieu, N.; Deacon, Niall; Marley, M. S.; van Spaandonk, L.; Baker, D.; Allard, F.; Andrei, A.H.; Canty, J.; Clarke, J.; Day-Jones, A. C.; Dupuy, T.; Fortney, J. J.; Gomes, J.; Ishii, M.; Jones, H.R.A.; Liu, M.; Magazzu, A.; Marocco, F.; Murray, D. N.; Rojas-Ayala, B.; Tamura, M. (2013-07)
      We report the discovery of 76 new T dwarfs from the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). Near-infrared broad- and narrow-band photometry and spectroscopy are presented for the new objects, along ...

    • 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 ...

    • The brightest pure-H ultracool white dwarf 

      Catalan, S.; Tremblay, P. -E.; Pinfield, D.J.; Smith, Leigh; Zhang, Z. H.; Napiwotzki, R.; Marocco, F.; Day-Jones, A. C.; Gomes, J.; Forde, K.P.; Lucas, P.W.; Jones, H.R.A. (2012-10)
      We report the identification of LSR J0745+2627 in the United Kingdom InfraRed Telescope Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) as a cool white dwarf with kinematics and age compatible with the thick-disk/halo ...

    • 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 ...

    • The discovery of the T8.5 dwarf UGPS J0521+3640 

      Burningham, B.; Lucas, P.W.; Leggett, S.K.; Smart, R.; Baker, D.; Pinfield, D.J.; Tinney, C. G.; Homeier, D.; Allard, F.; Zhang, Z. H.; Gomes, J.; Day-Jones, A. C.; Jones, H.R.A.; Kovacs, G.; Lodieu, N.; Marocco, F.; Murray, D. N.; Sipocz, B. (2011-06)
      We have carried out a search for late-type T dwarfs in the UKIRT Infrared Deep Sky Survey Galactic Plane Survey 6th Data Release. The search yielded two persuasive candidates, both of which have been confirmed as T dwarfs. ...

    • The extremely red L dwarf ULAS J222711-004547-dominated by dust 

      Marocco, F.; Day-Jones, A. C.; Lucas, P.W.; Jones, H.R.A.; Smart, R.L.; Zhang, Z. H.; Gomes, J. I.; Burningham, B.; Pinfield, D.J.; Raddi, R.; Smith, Leigh (2014-03)
      We report the discovery of a peculiar L dwarf from the United Kingdom Infrared Deep Sky Survey Large Area Survey, ULAS J222711-004547. The very red infrared photometry (MKO J-K = 2.79 +/- 0.06, WISEW1-W2 = 0.65 +/- 0.05) ...

    • A hot Uranus orbiting the super metal-rich star 77338 and the metallicity-mass connection 

      Jenkins, J. S.; Jones, H.R.A.; Tuomi, M.; Murgas, F.; Hoyer, S.; Jones, M. I.; Barnes, J. R.; Pavlenko, Y. V.; Ivanyuk, O.; Rojo, P.; Jordan, A.; Day-Jones, A. C.; Ruiz, M. T.; Pinfield, D.J. (2013-04-01)
      We announce the discovery of a low-mass planet orbiting the super metal-rich K0V star HD 77338 as part of our ongoing Calan-Hertfordshire Extrasolar Planet Search. The best-fit planet solution has an orbital period of ...

    • 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 ...

    • A large spectroscopic sample of L and T dwarfs from UKIDSS LAS : peculiar objects, binaries, and space density 

      Marocco, F.; Jones, H.R.A.; Day-Jones, A. C.; Pinfield, D.J.; Lucas, P.W.; Burningham, B.; Zhang, Z. H.; Smart, R.L.; Gomes, J. I.; Smith, L. (2015-06-01)
      We present the spectroscopic analysis of a large sample of late-M, L, and T dwarfs from UKIDSS. Using the YJHK photometry from ULAS and the red-optical photometry from SDSS we selected a sample of 262 brown dwarf candidates ...

    • 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 Planetary Systems from the Calan-Hertfordshire Extrasolar Planet Search and the Core Accretion Mass Limit 

      Jenkins, J. S.; Jones, Hugh; Tuomi, Mikko; Diaz, M.; Cordero, J. P.; Aguayo, A.; Pantoja, B.; Arriagada, P.; Mahu, R.; Brahm, R.; Rojo, P.; Soto, M. G.; Ivanyuk, O.; Becerra Yoma, N.; Day-Jones, A. C.; Ruiz, M. T.; Pavlenko, Y. V.; Barnes, J. R.; Murgas, F.; Pinfield, David; Jones, M. I.; Lopez-Morales, M.; Shectman, S.; Butler, R. P.; Minniti, D. (2017-04-01)
      We report the discovery of eight new giant planets, and updated orbits for four known planets, orbiting dwarf and subgiant stars using the CORALIE, HARPS, and MIKE instruments as part of the Calan–Hertfordshire Extrasolar ...

    • 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 ...

    • 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 ...

    • 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 ...

    • Two new ultracool benchmark systems from WISE+2MASS 

      Gomes, J. I.; Pinfield, D.J.; Marocco, F.; Day-Jones, A. C.; Burningham, B.; Zhang, Z. H.; Jones, H.R.A.; van Spaandonk, L.; Weights, D. (2013-05)
      We have used the Two-Micron All-Sky Survey and the Wide-field Infrared Survey Explorer to look for ultracool dwarfs that are part of multiple systems containing main-sequence stars. We cross-matched L dwarf candidates from ...