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Browsing by Subject "Galaxy: halo"

Browsing by Subject "Galaxy: halo"

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  • Abundance analysis of SDSS J134338.67+484426.6; an extremely metal-poor star from the MARVELS pre-survey 
    Susmitha Rani, A; Sivarani, T; Beers, T. C; Fleming, S; Mahadevan, S; Ge, J (Oxford University Press on behalf of the Royal Astronomical Society, 2016-05)
    We present an elemental-abundance analysis of an extremely metal-poor (EMP; [Fe/H] <−3.0) star, SDSS J134338.67+484426.6, identified during the course of the Multi-object Apache Point Observatory Radial Velocity Exoplanet ...
  • Carbon-enhanced Metal-poor Stars in the Inner and Outer Halo Components of the Milky Way 
    Carollo, D; Beers, T. C; Bovy, Jo; Sivarani, T; Norris, J. E; Freeman, K. C; Aoki, W; Lee, Young Sun; Kennedy, C. R (IOP Publishing, 2012-01-10)
    Carbon-enhanced metal-poor (CEMP) stars in the halo components of the Milky Way are explored, based on accurate determinations of the carbon-to-iron ([C/Fe]) abundance ratios and kinematic quantities for over 30,000 ...
  • The Case for the Dual Halo of the Milky Way 
    Beers, T. C; Carollo, D; Ivezic, Z; An, D; Chiba, M; Norris, J. E; Freeman, K. C; Lee, Young Sun; Munn, J. F; Re Fiorentin, P; Sivarani, T; Wilhelm, R; Yanny, B; York, D. G (IOP Publishing, 2012-02-10)
    Carollo et al. have recently resolved the stellar population of the Milky Way halo into at least two distinct components, an inner halo and an outer halo. This result has been criticized by Schönrich et al., who claim that ...
  • First stars. XIII. Two extremely metal-poor RR Lyrae stars 
    Hansen, C. J; Nordström, B; Bonifacio, P; Spite, M; Andersen, J; Beers, T. C; Cayrel, R; Spite, F; Molaro, P; Barbuy, B; Depagne, E; François, P; Hill, V; Plez, B; Sivarani, T (EDP Sciences, 2011-03)
    Context. The chemical composition of extremely metal-poor stars (EMP stars; [Fe/H] < ~ −3) is a unique tracer of early nucleosynthesis in the Galaxy. As such stars are rare, we wish to find classes of luminous stars ...
  • A high-resolution spectroscopic study of two new Na- and Al-rich field giants–likely globular cluster escapees in the galactic halo 
    Bandyopadhyay, A; Sivarani, T; Beers, T. C; Susmitha Rani, A (Oxford University Press on behalf of the Royal Astronomical Society, 2020-05)
    The stars SDSS J0646+4116 and SDSS J1937+5024 are relatively bright stars that were initially observed as a part of the SDSS/MARVELS pre-survey. They were selected, on the basis of their weak CH G bands, along with a total ...
  • High-resolution spectroscopy of extremely metal-poor stars from SDSS/SEGUE. I. Atmospheric parameters and chemical compositions 
    Aoki, W; Beers, T. C; Lee, Young Sun; Honda, S; Ito, H; Takada-Hidai, M; Frebel, A; Suda, T; Fujimoto, M. Y; Carollo, D; Sivarani, T (IOP Publishing, 2013-01)
    Chemical compositions are determined based on high-resolution spectroscopy for 137 candidate extremely metalpoor (EMP) stars selected from the Sloan Digital Sky Survey (SDSS) and its first stellar extension, the ...
  • The M31 pixel lensing plan campaign: macho lensing and self-lensing signals 
    Novati, S. C; Bozza, V; Bruni, I; Dall'Ora, M; Paolis, F. D; Dominik, M; Gualandi, R; Ingrosso, G; Jetzer, P; Mancini, L; Nucita, A; Safonova, M; Scarpetta, G; Sereno, M; Strafella, F; Subramaniam, A; Gould, A (IOP Publishing, 2014-03-10)
    We present the final analysis of the observational campaign carried out by the PLAN (Pixel Lensing Andromeda) collaboration to detect a dark matter signal in form of MACHOs through the microlensing effect. The campaign ...
  • The metal-poor end of the Spite plateau I. Stellar parameters, metallicities, and lithium abundances 
    Sbordone, L; Bonifacio, P; Caffau, E; Ludwig, H. -G; Behara, N. T; González Hernández, J. I; Steffen, M; Cayrel, R; Freytag, B; Van’t Veer, C; Molaro, P; Plez, B; Sivarani, T; Spite, M; Spite, F; Beers, T. C; Christlieb, N; François, P; Hill, V (EDP Sciences, 2010-11)
    Context. The primordial nature of the Spite plateau is at odds with the WMAP satellite measurements, implying a primordial Li production at least three times higher than observed. It has also been suggested that A(Li) might ...
  • The Milky Way Tomography with SDSS. III. Stellar Kinematics 
    Bond, N. A; Ivezić, Z; Sesar, B; Jurić, M; Munn, J. A; Kowalski, A; Loebman, S; Roškar, R; Beers, T. C; Dalcanton, J; Rockosi, C. M; Yanny, B; Newberg, H. J; Prieto, C. A; Wilhelm, R; Lee, Y. S; Sivarani, T; Majewski, S. R; Norris, J. E; Bailer-Jones, C. A. L; Fiorentin, P. R; Schlegel, D; Uomoto, A; Lupton, R. H; Knapp, G. R; Gunn, J. E; Covey, K. R; Smith, J. A; Miknaitis, G; Doi, M; Tanaka, M; Fukugita, M; Kent, S; Finkbeiner, D; Quinn, T. R; Hawley, S; Anderson, S; Kiuchi, F; Chen, A; Bushong, J; Sohi, H; Haggard, D; Kimball, A; McGurk, R; Barentine, J; Brewington, H; Harvanek, M; Kleinman, S; Krzesinski, J; Long, D; Nitta, A; Snedden, S; Lee, B; Pier, J. R; Harris, H; Brinkmann, J; Schneider, D. P (IOP Publishing, 2010-06-10)
    We study Milky Way kinematics using a sample of 18.8 million main-sequence stars with r < 20 and proper-motion measurements derived from Sloan Digital Sky Survey (SDSS) and POSS astrometry, including ~170,000 stars with ...
  • [O/Fe] Estimates for Carbon-enhanced Metal-poor Stars from Near-infrared Spectroscopy 
    Kennedy, C. R; Sivarani, T; Beers, T. C; Lee, Y. S; Placco, V. M; Rossi, S; Christlieb, N; Herwig, F; Plez, B (IOP Publishing, 2011-03)
    We report on oxygen abundances determined from medium-resolution near-infrared spectroscopy for a sample of 57 carbon-enhanced metal-poor (CEMP) stars selected from the Hamburg/ESO Survey. The majority of our program stars ...
  • Optical and NIR spectroscopy of cool CEMP stars to probe the nucleosynthesis in low-mass AGB binary system 
    Susmitha, A; Ojha, D. K; Sivarani, T; Ninan, J. P; Bandyopadhyay, A; Surya, Arun; Unni, Athira (Oxford University Press on behalf of Royal Astronomical Society, 2021-09)
    We present the abundance analyses of seven carbon enhanced metal-poor (CEMP) stars to understand the origin of carbon in them. We used high-resolution optical spectra to derive abundances of various elements. We also used ...
  • Searches for Metal-poor Stars from the Hamburg/ESO Survey Using the CH G Band 
    Placco, V. M; Kennedy, C. R; Beers, T. C; Christlieb, N; Rossi, S; Sivarani, T; Lee, Young Sun; Reimers, D; Wisotzki, L (IOP Publishing, 2011-12)
    We describe a new method to search for metal-poor candidates from the Hamburg/ESO objective-prism survey (HES) based on identifying stars with apparently strong CH G-band strengths for their colors. The hypothesis we exploit ...
  • Upper Limits on O VI Emission from Voyager Observations 
    Murthy, J (Indian Academy of Sciences, 2002-06)
    We have examined 426 Voyager fields distributed across the sky for O VI (1032/1038 Å) emission from the Galactic diffuse interstellar medium. No such emission was detected in any of our observed fields. Our most constraining ...

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