Probing the origin of primordial minihalos with gravitational lensing

2015 Fiscal Year Final Research Report

• Project/Area Number: 25287062
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Kinki University
• Principal Investigator: INOUE Kaiki 近畿大学, 理工学部, 准教授 (70388495)
• Co-Investigator(Kenkyū-buntansha): CHIBA Masashi 東北大学, 大学院理学研究科, 教授 (50217246) ; MINEZAKI Takeo 東京大学, 大学院理学研究科, 助教 (60292835) ; TAKAHASHI Ryuichi 弘前大学, 理工学研究科, 助教 (60413960)
• Research Collaborator: MATSUSHITA Satoki 中央研究院天文及天文物理研究所, 副研究員
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: ダークマター / 重力レンズ / 宇宙論 / 銀河形成 / サブハロー / サブミリ波 / フラックス比異常 / 矮小銀河

Outline of Final Research Achievements

We estimated the lensing effect caused by subhalos in a lensing galaxy and dark matter structures in the line-of-sight using quadruple gravitational lenses. We found that: 1) The observed data are consistent with the cold dark matter (CDM) based cosmological model. 2) The observed data are not consistent with the warm dark matter (WDM) model if the WDM mass is smaller than 1/400 of the electron mass. These results imply that the origin of primordial minihalos, which are considered to be the progenitors of primordial galaxies is CDM rather tan WDM. On the other hand, we found that observational data of the Milky Way and the Andromeda galaxies suggest that some associated dwarf galaxies have a core rather than a cusp. This relult is not consistent with the CDM prediction.

Free Research Field

宇宙論