Research Interests: Galaxy Formation and Evolution
- Progenitors of Type Ia Supernovae (SNe Ia)
- NOT the double-degenerate but the single-degenerate scenario, where the progenitor is a pair of white dwarf and normal star.
- In terms of the evolution of the binary system, the metallicity effect is important on the occurrence of SNe Ia (Kobayashi et al. 1998).
- The observed scatter of the SNIa luminosity can be explained (Umeda et al. 1999).
- The dust effect on the SNIa cosmology is estimated (Totani & Kobayashi 1999).
- Cosmic and Galactic Chemical Evolution
- Chemical abundances are fossils to tell us the star formation history of galaxies and the universe.
This is because stars formed from gas clouds in a galaxy, ejected heavy elements into the interstellar medium via supernovae.
Different heavy elements are produced different supernovae with different timescales.
- One zone-model, with which I can make an galaxy in two minutes:) (Kobayashi, Tsujimoto, Nomoto 00)
- Cosmological Simulation, which takes 2 weeks... (Kobayashi, Springel, White 06)
- Spatial Distribution of Heavy Elements in galaxies and the Universe
- In such internal structure of a galaxy, formation history of the galaxy is imprinted.
- Observed metallicity gradients of nearby elliptical galaxies (Kobayashi & Arimoto 99)
- Observed color gradients of distant (z<1) elliptical galaxies (Tamura, Kobayashi, et al. 00)
- GRAPE-SPH Chemodynamical Simulation
- I simulate the formation and evolution of more than a hundred elliptical galaxies from the CDM initial fluctuation. GRAPE is a Japan-made special computer to calculate gravity.
- By reproducing the observed variety of radial metallicity gradients, I conclude that not all ellipticals formed by major mergers, but some of them formed monolithically (Kobayashi 2004).
- The observed scaling relations and fundamental planes can be reproduced (Kobayashi 2005).
- Chemodynamical evolution of the Milky Way Galaxy (Kobayashi, Nakasato, in prep.)
- Feedback and Chemical Enrichment with GADGET
- I've introduced my schemes of feedback and chemical enrichment into GADGET, which is widely used parallel SPH code, German-made.
- I succeed in blowing the galactic winds from a small disk galaxy, not by hand but by supernova thermal feedback.
- Cosmic SFRs, chemical evolution, galactic winds, and the mass-metallicity relation of galaxies (Kobayashi, Springel, White 06)
- Origin of Galactic Morphology
- How did spiral and elliptical galaxies form? What are dwarf galaxies? What are DLA, LBG, ERO, DRG, BzK,...
- Environmental Effect
- Galaxy formation in fields vs clusters? Elemental abundance patterns of ICM?
- Nucleosynthesis of hypernovae (Kobayashi, Umeda, Tominaga, et al. 06)
- Gamma-ray burst rates (Kobayashi, Maeda, in prep.)
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