Browsing by Author "Kobayashi, C."

Now showing items 1-20 of 32

    • The ALMA REBELS Survey : the dust content of z ∼7 Lyman break galaxies 

      Dayal, P.; Ferrara, A.; Sommovigo, L.; Bouwens, R.; Oesch, P. A.; Smit, R.; Gonzalez, V.; Schouws, S.; Stefanon, M.; Kobayashi, C.; Bremer, J.; Algera, H. S. B.; Aravena, M.; Bowler, R. A. A.; Cunha, E. da; Fudamoto, Y.; Graziani, L.; Hodge, J.; Inami, H.; Looze, I. De; Pallottini, A.; Riechers, D.; Schneider, R.; Stark, D.; Endsley, R. (2022-03-03)
      We include a fully coupled treatment of metal and dust enrichment into the Delphi semi-analytic model of galaxy formation to explain the dust content of 13 Lyman break galaxies (LBGs) detected by the Atacama Large millimetre ...

    • The Aquila comparison project : the effects of feedback and numerical methods on simulations of galaxy formation. 

      Scannapieco, C.; Wadepuhl, M.; Parry, O. H.; Navarro, J. F.; Jenkins, A.; Springel, V.; Teyssier, R.; Carlson, E.; Couchman, H. M. P.; Crain, R. A.; Dalla Vecchia, C.; Frenk, C. S.; Kobayashi, C.; Monaco, P.; Murante, G.; Okamoto, T.; Quinn, T.; Schaye, J.; Stinson, G. S.; Theuns, T.; Wadsley, J.; White, S. D. M.; Woods, R. (2012-06)
      We compare the results of various cosmological gas-dynamical codes used to simulate the formation of a galaxy in the ? cold dark matter structure formation paradigm. The various runs (13 in total) differ in their numerical ...

    • Barium lines in high-quality spectra of two metal-poor giants in the Galactic halo 

      Cescutti, G.; Morossi, C.; Franchini, M.; Marcantonio, P. Di; Chiappini, C.; Steffen, M.; Valentini, M.; François, P.; Christlieb, N.; Cortés, C.; Kobayashi, C.; Depagne, E. (2021-10-01)
      Context. Theoretical results showed the possibility that neutron capture elements were produced in the early Universe by two different sources: a frequent s-process source hosted by rotating massive stars, and a rare ...

    • The Chemical Evolution of Fluorine in the Bulge - High-resolution K-band spectra of giants in three fields 

      Jönsson, H.; Ryde, N.; Harper, G. M.; Cunha, K.; Schultheis, M.; Eriksson, K.; Kobayashi, C.; Smith, V. V.; Zoccali, M. (2014-04-17)
      Possible main formation sites of F in the Universe include AGB stars, the {\nu}-process in Type II SNe, and/or W-R stars. The importance of the W-R stars has theoretically been questioned and they are probably not needed ...

    • Chemodynamical evolution of elliptical galaxies : Metallicity gradients and scaling relations 

      Kobayashi, C. (2004-01)
      We simulate the chemodynamical evolution of a hundred elliptical galaxies using our GRAPE-SPH code, and succeed in reproducing the radial metallicity gradients and the global scaling relations such as the fundamental plane. ...

    • Chemodynamical evolution of galaxies 

      Kobayashi, C. (2002-07)
      I simulate the chemodynamical evolution of the Milky Way and elliptical galaxies using the GRAPE-SPH code. By reproducing the observations, I discuss the origin of elliptical galaxies

    • Chemodynamical evolution of the Milky Way 

      Kobayashi, C.; Nakasato, N.; Nomoto, K. (Astronomical Society of the Pacific, 2003)
      We simulate the chemodynamical evolution of the Milky Way using our GRAPE-SPH code, and reproduce the age-metallicity relation, the [O/Fe]-[Fe/H] relation, and the metallicity distribution.

    • Constraining Nucleosynthesis in Two CEMP Progenitors Using Fluorine 

      Mura-Guzmán, A.; Yong, D.; Abate, C.; Karakas, A.; Kobayashi, C.; Oh, H.; Chun, S.; Mace, G.; . (2020-11-01)
      We present new fluorine abundance estimations in two carbon enhanced metal-poor (CEMP) stars, HE 1429-0551 and HE 1305+0007. HE 1429-0551 is also enriched in slow neutron-capture process (s-process) elements, a CEMP-s, and ...

    • Direct measurements of carbon and sulfur isotope ratios in the Milky Way 

      Yan, Y. T.; Henkel, C.; Kobayashi, C.; Menten, K. M.; Gong, Y.; Zhang, J. S.; Yu, H. Z.; Yang, K.; Xie, J. J.; Wang, X.Y. (2023-02-14)
      With the IRAM 30-m telescope, we performed observations of the $J$ = 2-1 transitions of CS, C$^{33}$S, C$^{34}$S, C$^{36}$S, $^{13}$CS, $^{13}$C$^{33}$S, and $^{13}$C$^{34}$S as well as the $J$ = 3-2 transitions of C$^{33}$S, ...

    • Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way 

      Howes, L. M.; Casey, A. R.; Asplund, M.; Keller, S. C.; Yong, D.; Nataf, D. M.; Poleski, R.; Lind, K.; Kobayashi, C.; Owen, C. I.; Ness, M.; Bessell, M. S.; Costa, G. S. Da; Schmidt, B. P.; Tisserand, P.; Udalski, A.; Szymański, M. K.; Soszyński, I.; Pietrzyński, G.; Ulaczyk, K.; Wyrzykowski, Ł.; Pietrukowicz, P.; Skowron, J.; Kozłowski, S.; Mróz, P. (2015-11-26)
      The first stars are predicted to have formed within 200 million years after the Big Bang, initiating the cosmic dawn. A true first star has not yet been discovered, although stars with tiny amounts of elements heavier than ...

    • The Gaia-ESO survey: the non-universality of the age-chemical-clocks-metallicity relations in the Galactic disc 

      Casali, G.; Spina, L.; Magrini, L.; Karakas, A.; Kobayashi, C.; Casey, A. R.; Feltzing, S.; Swaelmen, M. Van der; Tsantaki, M.; Jofré, P.; Bragaglia, A.; Feuillet, D.; Bensby, T.; Biazzo, K.; Gonneau, A.; Tautvaisiene, G.; Baratella, M.; Roccatagliata, V.; Pancino, E.; Adibekyan, V.; Martell, S.; Bayo, A.; Jeffries, R. D.; Gilmore, G.; Randich, S.; Alfaro, E.; Koposov, S. E.; Korn, A. J.; Recio-Blanco, A.; Smiljanic, R.; Franciosini, E.; Hourihane, A.; Monaco, L.; Morbidelli, L.; Sacco, G.; Worley, C.; Zaggia, S. (2020-07-21)
      In the era of large spectroscopic surveys, massive databases of high-quality spectra provide tools to outline a new picture of our Galaxy. In this framework, an important piece of information is provided by our ability to ...

    • Galactic chemical evolution : Carbon through zinc 

      Kobayashi, C.; Umeda, Hideyuki; Nomoto, Ken'ichi; Tominaga, Nozomu; Ohkubo, Takuya (2006-12-20)
      We calculate the evolution of heavy-element abundances from C to Zn in the solar neighborhood, adopting our new nucleosynthesis yields. Our yields are calculated for wide ranges of metallicity (Z = 0-Z circle dot) and the ...

    • The GALAH Survey : Non-LTE departure coefficients for large spectroscopic surveys 

      Amarsi, A. M.; Lind, K.; Osorio, Y.; Nordlander, T.; Bergemann, M.; Reggiani, H.; Wang, E. X.; Buder, S.; Asplund, M.; Barklem, P. S.; Wehrhahn, A.; Skúladóttir, Á.; Kobayashi, C.; Karakas, A. I.; Gao, X. D.; Bland-Hawthorn, J.; Silva, G. M. De; Kos, J.; Lewis, G. F.; Martell, S. L.; Sharma, S.; Simpson, J. D.; Zucker, D. B.; Čotar, K.; Horner, J.; collaboration, the GALAH (2020-10-06)
      Massive sets of stellar spectroscopic observations are rapidly becoming available and these can be used to determine the chemical composition and evolution of the Galaxy with unprecedented precision. One of the major ...

    • GRAPE-SPH chemodynamical simulation of elliptical galaxies - I : Evolution of metallicity gradients 

      Kobayashi, C. (2004-01-21)
      We simulate the formation and chemodynamical evolution of 124 elliptical galaxies using a GRAPE-SPH code that includes various physical processes that are associated with the formation of stellar systems: radiative cooling, ...

    • GRAPE-SPH chemodynamical simulation of elliptical galaxies - II : Scaling relations and the fundamental plane 

      Kobayashi, C. (2005-08-21)
      We simulate the formation and chemodynamical evolution of 128 elliptical galaxies using a GRAPE-SPH code that includes various physical processes that are associated with the fort-nation of stellar systems: radiative ...

    • High resolution spectroscopic follow-up of the most metal-poor candidates from SkyMapper DR1.1 

      Yong, D.; Costa, G. S. Da; Bessell, M. S.; Chiti, A.; Frebel, A.; Gao, X.; Lind, K.; Mackey, A. D.; Marino, A. F.; Murphy, S. J.; Nordlander, T.; Asplund, M.; Casey, A. R.; Kobayashi, C.; Norris, J. E.; Schmidt, B. P. (2021-11-01)
      We present chemical abundances for 21 elements (from Li to Eu) in 150 metal-poor Galactic stars spanning -4.1 < [Fe/H] < -2.1. The targets were selected from the SkyMapper survey and include 90 objects with [Fe/H] ≤ -3 of ...

    • HII Region Metallicity Constraints Near the Site of the Strongly Lensed Supernova "SN Refsdal" at Redshift 1.49 

      Yuan, T. -T.; Kobayashi, C.; Kewley, L. J. (2015-04-27)
      We present the local HII region metallicity near the site of the recently discovered multiply lensed supernova (SN; "SN Refsdal") at redshift 1.49. "SN Refsdal" is located at the outer spiral arm ($\sim$7 kpc) of the lensed ...

    • Lifetime of Type Ia Supernovae and chemical evolution of Galaxies 

      Kobayashi, C.; Nomoto, K. (2003-05-05)

    • The MAGPI Survey -- science goals, design, observing strategy, early results and theoretical framework 

      Foster, C.; Mendel, J. T.; Lagos, C. D. P.; Wisnioski, E.; Yuan, T.; D'Eugenio, F.; Barone, T. M.; Harborne, K. E.; Vaughan, S. P.; Schulze, F.; Remus, R. -S.; Gupta, A.; Collacchioni, F.; Khim, D. J.; Taylor, P.; Bassett, R.; Croom, S. M.; McDermid, R. M.; Poci, A.; Battisti, A. J.; Bland-Hawthorn, J.; Bellstedt, S.; Colless, M.; Davies, L. J. M.; Derkenne, C.; Driver, S.; Ferré-Mateu, A.; Fisher, D. B.; Gjergo, E.; Johnston, E. J.; Khalid, A.; Kobayashi, C.; Oh, S.; Peng, Y.; Robotham, A. S. G.; Sharda, P.; Sweet, S. M.; Taylor, E. N.; Tran, K. -V. H.; Trayford, J. W.; Sande, J. van de; Yi, S. K.; Zanisi, L. (2021-07-26)
      We present an overview of the Middle Ages Galaxy Properties with Integral Field Spectroscopy (MAGPI) survey, a Large Program on ESO/VLT. MAGPI is designed to study the physical drivers of galaxy transformation at a lookback ...

    • Metallicity gradients in disks : Do galaxies form inside-out? 

      Pilkington, K.; Few, C. G.; Gibson, B. K.; Calura, F.; Michel-Dansac, L.; Thacker, R. J.; Molla, M.; Matteucci, F.; Rahimi, A.; Kawata, D.; Kobayashi, C.; Brook, C. B.; Stinson, G. S.; Couchman, H. M. P.; Bailin, J.; Wadsley, J. (2012-04)
      Aims. We examine radial and vertical metallicity gradients using a suite of disk galaxy hydrodynamical simulations, supplemented with two classic chemical evolution approaches. We determine the rate of change of gradient ...