Browsing by Author "Centre for Astrophysics Research (CAR)"

Now showing items 61-80 of 3233

    • The absence of an environmental dependence in the mass-metallicity relation at z = 2 

      Kacprzak, Glenn G.; Yuan, Tiantian; Nanayakkara, Themiya; Kobayashi, Chiaki; Tran, Kim V. Y. H.; Kewley, Lisa J.; Glazebrook, Karl; Spitler, Lee; Taylor, Philip; Cowley, Michael; Labbe, Ivo; Straatman, Caroline; Tomczak, Adam (2015-04-02)
      We investigate the environmental dependence of the mass-metallicity relation at z = 2 with MOSFIRE/Keck as part of the ZFIRE survey. Here, we present the chemical abundance of a Virgo-like progenitor at z = 2.095 that has ...

    • The Absence of Diffuse Gas around the Dwarf Spheroidal Galaxy Leo I 

      Bowen, D.V.; Tolstoy, E.; Ferrera, A.; Blades, J.C.; Brinks, E. (1997)
      We have obtained spectra of three QSO/AGNs with the GHRS aboard the Hubble Space Telescope to search for absorption from low column density gas in the halo of the dwarf spheroidal (dSph) galaxy Leo I. The probe sight lines ...

    • ABSOLUTE PROPER MOTIONS OUTSIDE the PLANE (APOP) - A STEP TOWARD the GSC2.4 

      Qi, Zhaoxiang; Yu, Yong; Bucciarelli, Beatrice; Lattanzi, Mario G.; Smart, Richard L.; Spagna, Alessandro; McLean, Brian J.; Tang, Zhenghong; Jones, H.R.A.; Morbidelli, Roberto; Nicastro, Luciano; Vecchiato, Alberto (2015-10-06)
      We present a new catalog of absolute proper motions and updated positions derived from the same Space Telescope Science Institute digitized Schmidt survey plates utilized for the construction of Guide Star Catalog II. As ...

    • Absorbers and Globular Cluster Formation in Powerful High Redshift Radio Galaxies 

      Krause, M. (2002-04-01)
      A radiative hydrodynamic simulation for a typical, powerful high redshift radio galaxy is presented. The jet is injected at one third the speed of light into a 10 000 times denser, homogeneous medium. In the beginning of ...

    • The abundance distribution of stars with planets 

      Bond, J.; Tinney, C.G.; Butler, R.P.; Jones, H.R.A.; Marcy, G.W.; Penny, A.J.; Carter, B.D. (2006)
      We present the results of a uniform, high-precision spectroscopic metallicity study of 136 G-type stars from the Anglo-Australian Planet Search, 20 of which are known to harbour extrasolar planets (as at July 2005). ...

    • An abundance of small exoplanets around stars with a wide range of metallicities 

      Buchhave, Lars A.; Latham, David W.; Johansen, Anders; Bizzarro, Martin; Torres, Guillermo; Rowe, Jason F.; Batalha, Natalie M.; Borucki, William J.; Brugamyer, Erik; Caldwell, Caroline; Bryson, Stephen T.; Ciardi, David R.; Cochran, William D.; Endl, Michael; Esquerdo, Gilbert A.; Ford, Eric B.; Geary, John C.; Gilliland, Ronald L.; Hansen, Terese; Isaacson, Howard; Laird, John B.; Lucas, P.W.; Marcy, Geoffrey W.; Morse, Jon A.; Robertson, Paul; Shporer, Avi; Stefanik, Robert P.; Still, Martin; Quinn, Samuel N. (2012-06-21)
      The abundance of heavy elements (metallicity) in the photospheres of stars similar to the Sun provides a 'fossil' record of the chemical composition of the initial protoplanetary disk. Metal-rich stars are much more likely ...

    • Abundance uncertainties obtained with the PIZBUIN framework for Monte Carlo reaction rate variations 

      Rauscher, T.; Nishimura, N.; Cescutti, G.; Hirschi, R.; Murphy, A. St J. (American Institute of Physics (AIP), 2018-04-25)
      Uncertainties in nucleosynthesis models originating from uncertainties in astrophysical reaction rates were estimated in a Monte Carlo variation procedure. Thousands of rates were simultaneously varied within individual, ...

    • Abundances and Evolution of Lithium in the Galactic Halo and Disk 

      Ryan, Sean G.; Kajino, T.; Beers, T.C.; Suzuki, T.K.; Romano, D.; Matteucci, F.; Rosolankova, K. (2001-03)
      We have measured the Li abundance of 18 stars with [2[[Fe/H][[1 and 6000[Teff[6400 K, a parameter range that was poorly represented in previous studies. We examine the Galactic chemical evolution (GCE) of this element, ...

    • Abundances and Kinematics of Extremely Metal-Deficient, Carbon-Rich Halo Stars 

      Tsangarides, S.; Ryan, Sean G.; Beers, T.C. (Astronomical Society of the Pacific, 2003)
      To study the possible nucleosynthetic backgrounds of extremely metal-deficient, carbon-rich (EMDC) stars, we have conducted high-resolution spectroscopy of 26 candidate objects selected from HK-survey stars with [Fe/H]? ...

    • Abundances in the atmosphere of the metal-rich planet-host star HD 77338 

      Kushniruk, I.O.; Pavlenko, Ya. V.; Jenkins, J.S.; Jones, Hugh (2014)
      Abundances of Fe, Si, Ni, Ti, Na, Mg, Cu, Zn, Mn, Cr and Ca in the atmosphere of the K-dwarf HD 77338 are determined and discussed. HD 77338 hosts a hot Uranus-like planet and is currently the most metal-rich single star ...

    • Abundances in very metal-poor stars 

      Ryan, Sean G. (Institut d'Astrophysique et de Geophysique, 2000)
      Metal-poor stars provide information on the characteristics and chemical evolution of the halo population of the Galaxy, the first epoch of star formation and Galaxy formation (not just locally but with relevance to ...

    • Abundances of UV bright stars in globular clusters. I. ROA 5701 in omega Centauri and Barnard 29 in M 13 

      Moehler, S.; Heber, U.; Lemke, M.; Napiwotzki, R. (1998)
      Two UV brights stars in globular clusters, ROA 5701 (ω Cen) and Barnard 29 (M 13) are analysed from high-resolution UV and optical spectra. The main aim is the measurement of iron abundances from UV spectra obtained with ...

    • Abundant molecular gas in the intergalactic medium of Stephan's Quintet 

      Lisenfeld, U.; Braine, J.; Duc, P.A.; Leon, S.; Charmandaris, V.; Brinks, E. (2002-11)
      Stephan's Quintet (SQ) is a system consisting of at least four interacting galaxies which is well known for its complex dynamical and star formation history. It possesses a rich intergalactic medium (IGM), where hydrogen ...

    • Abundant molecular gas in tidal dwarf galaxies: On-going galaxy formation 

      Braine, J.; Duc, P.A.; Lisenfeld, U.; Charmandaris, V.; Vallejo, O.; Leon, S.; Brinks, E. (2001-10)
      We investigate the process of galaxy formation as can be observed in the only currently forming galaxies { the so-called Tidal Dwarf Galaxies, hereafter TDGs { through observations of the molecular gas detected via its CO ...

    • ACA [CI] observations of the starburst galaxy NGC 253 

      Krips, M.; Martín, S.; Sakamoto, K.; Aalto, S.; Bisbas, T.~G.; Bolatto, A.~D.; Downes, D.; Eckart, A.; Feruglio, C.; García-Burillo, S.; Geach, J.; Greve, T.~R.; König, S.; Matsushita, S.; Neri, R.; Offner, S.; Peck, A.~B.; Viti, S.; Wagg, J. (2016-08-01)
      Context. Carbon monoxide (CO) is widely used as a tracer of the molecular gas in almost all types of environments. However, several shortcomings of CO complicate usaging it as H2 tracer, such as its optical depth effects, ...

    • Accretion Disk Wind of Hercules X-1 during the Short High State 

      Kosec, P.; Kara, E.; Fabian, A. C.; Pinto, C.; Psaradaki, I.; Rogantini, D.; Staubert, R.; Walton, D. J. (2023-12-05)
      Hercules X-1 is a nearly edge-on X-ray binary with a warped, precessing accretion disk, which manifests through a 35-day cycle of alternating High and Low flux states. This disk precession introduces a changing line of ...

    • Accretion mode versus radio morphology in the LOFAR Deep Fields 

      Mingo, B.; Croston, J. H.; Best, P. N.; Duncan, K. J.; Hardcastle, M. J.; Kondapally, R.; Prandoni, I.; Sabater, J.; Shimwell, T. W.; Williams, W. L.; Baldi, R. D.; Bonato, M.; Bondi, M.; Dabhade, P.; Gürkan, G.; Ineson, J.; Magliocchetti, M.; Miley, G.; Pierce, J. C. S.; Röttgering, H. J. A. (2022-02-16)
      Radio-loud active galaxies have two accretion modes [radiatively inefficient (RI) and radiatively efficient (RE)], with distinct optical and infrared signatures, and two jet dynamical behaviours, which in arcsec- to ...

    • Activation method combined with characteristic X-ray counting : A possibility to measure (alpha, gamma) cross sections on heavy p-nuclei 

      Kiss, G. G.; Szuecs, T.; Gyuerky, Gy.; Fueloep, Zs.; Farkas, J.; Kertesz, Zs.; Somorjai, E.; Laubenstein, M.; Froehlich, C.; Rauscher, T. (2011-10-01)
      For an improved modeling of the astrophysical nucleosynthesis of p-nuclei, low energy cross section data of alpha-induced reactions on heavy isotopes are needed. Technical difficulties hamper the experimental determination ...

    • Active galactic nuclei heating in the centres of galaxy groups: a statistical study 

      Jetha, N.N.; Ponman, T.J.; Hardcastle, M.J.; Croston, J.H. (2007)
      We present gas temperature, density, entropy and cooling time profiles for the cores of a sample of 15 galaxy groups observed with Chandra.We find that the entropy profiles follow a power-law profile down to very small ...

    • An active galactic nucleus driven shock in the intracluster medium around the radio galaxy 3C310 

      Kraft, R.P.; Nulsen, P.E.J.; Forman, W.R.; Jones, C.; Murray, S.S.; Birkinshaw, M.; Worrall, D.M.; Croston, J.H.; Hardcastle, M.J. (2012-04-10)
      We present results from a 57.6 ks Chandra observation of the cluster gas associated with the fat-double radio galaxy 3C 310. We find a surface brightness discontinuity in the gas outside the southern radio lobe that we ...