Cosmological scenario based on inhomogeneous models

2009 Fiscal Year Final Research Report

• Project/Area Number: 19540279
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Nagoya University
• Principal Investigator: NAMBU Yasusada Nagoya University, 大学院・理学研究科, 准教授 (40212112)
• Project Period (FY): 2007 – 2009
• Keywords: 非一様宇宙 / 平均化ボイド / 光度距離 / ダークエネルギー

Research Abstract

Void models provide a possible explanation of the "accelerated expansion" of the Universe without dark energy. To make the conventional void models more realistic, we allow the void, an under-dense region around us, to be anisotropic and consider an average of the distance-redshift relations over the solid angle subtended at the observer. We first show that after taking the average of a form of the optical scalar equation (distance equation), the effective distance equation we obtain coincides with the one for the Lema^itre-Tolman- Bondi universe with a Dyer-Roeder-like extension. We then numerically solve the equation to compare with observational data of Type Ia supernovae. We find that anisotropy allows smaller size of void and larger Ωm.

Research Products

• [Journal Article] The distance-redshift relation for the inhomogeneous and anisotropic universe (2008)
  • Author(s): K. Iwata, Y. Nambu, M. Tanimoto
  • Journal Title: Proc. 18th workshop of general relativity and gravitation Pages: 241-244
• [Journal Article] Luminosity distance-redshift relation for the LTB solution near the center (2007)
  • Author(s): M. Tanimoto, Y. Nambu
  • Journal Title: Class. Quantum Grav. 24 Pages: 3843-3857
  • Peer Reviewed
• [Presentation] ボイドモデルにおける非等方性の効果 (2009)
  • Author(s): K. Iwata, Y. Nambu, M. Tanimoto
  • Organizer: 日本物理学会
  • Place of Presentation: 立教大学
  • Year and Date: 2009-03-30
• [Presentation] The distance-redshift relation for the inhomogeneous and anisotropic universe (2007)
  • Author(s): K. Iwata, Y. Nambu, M. Tanimoto
  • Organizer: 18th workshop of general relativity and gravitation
  • Place of Presentation: 広島大学
  • Year and Date: 2007-11-17
• [Remarks] [プレプリント] M. Tanimoto and Y. Nambu and K. Iwata“The role of anisotropy in the void models without dark energy"arXiv:0906.4857 [astro-ph.CO] (2009)
• [Remarks] [他大学でのセミナー]東京工業大学宇宙理論グループセミナー“The role of anisotropy in the void models without dark energy"2009年5月12日講演者:南部保貞