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아벨 2107 은하단의 분광 서베이: 은하단의 회전운동과 우주거대구조와의 연관성 SCI
  • 송현미;황호성;박창범;Rory Smith;Maret Einasto
  • 2018-12-20
  • THE ASTROPHYSICAL JOURNAL 869 2 : 124-1~124-8
We study the rotational motion of the galaxy cluster A2107 at redshift z = 0.04 and its connection to nearby large-scale structures using a large amount of spectroscopic redshift data. By combining 978 new redshifts from the MMT/Hectospec observations with data in the literature, we construct a large sample of 1968 galaxies with measured redshifts at clustercentric radius R < 60'. Our sample has high (80%) and spatially uniform completeness at r-band apparent magnitude ${m}_{r,\mathrm{Petro},0}\lt 19.1$. We first apply the caustic method to the sample and identify 285 member galaxies of A2107 at R < 60'. Then the rotation amplitude and the position angle of the rotation axis are measured. We find that the member galaxies show strong global rotation at R < 20' (v rot/σ v ~ 0.6) with a significance of >3.8σ, which is confirmed by two independent methods. The rotation becomes weaker in outer regions. There are at least five filamentary structures that are connected to the cluster and that consist of known galaxy groups. These structures are smoothly connected to the cluster, which seem to be inducing the global rotation of the cluster through inflow of galaxies.