The dark matter halo structure of "fossil" groups candidates

T. Yoshioka, A. Furuzawa, S. Takahashi, Y. Tawara, S. Sato, K. Yamashita, Y. Kumai

研究成果: Article査読

32 被引用数 (Scopus)


We investigated properties of four isolated giant elliptical galaxies with extended X-ray halo using ASCA data, The derived size of X-ray halo, X-ray luminosity, and gravitational mass of the dark halo are unusually large those of X-ray halo of a single galaxy, but are typical for X-ray halos of groups and poor clusters of galaxies. The measured temperatures and abundances of the X-ray halo gas in these galaxies are also similar to those of the groups and poor clusters. Based on these results we identified these galaxies as "isolated X-ray overluminous elliptical galaxy" (IOLEG). The radial profiles of dark halo in these objects were derived from X-ray data. It is found that some are similar to those of compact groups while others are the same as those of normal ellipticals. The dark halos of lOLEGs are thus indistinguishable from those of groups (and poor clusters), which appears to be consistent with a widely believed idea that lOLEGs are a product of dynamical evolution of a compact group. However, mass-to-light ratios of IOLEGs (M 200 /L B ∼ 100-1000) are far greater than those of Hickson compact groups M 200 /J B ∼ 40-60). Since it is hard to consider that total optical luminosity of a compact group decreases by an order of magnitude in the course of dynamical evolution, such difference in the observed mass-to-light ratio between IOLEGs and Hickson compact groups strongly suggests that most IOLEGs have not evolved from compact groups which are observed at present.

ジャーナルAdvances in Space Research
出版ステータスPublished - 2004

All Science Journal Classification (ASJC) codes

  • 航空宇宙工学
  • 天文学と天体物理学
  • 地球物理学
  • 大気科学
  • 宇宙惑星科学
  • 地球惑星科学(全般)


「The dark matter halo structure of "fossil" groups candidates」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。