摘要
We study the clustering property of extremely red objects (EROs) using Canada-France-Hawaii Telescope (CFHT) surveys with 0.55 deg <sup>2</sup> in the AKARI north ecliptic pole (NEP) deep field. EROs are selected by the color criterion of r′-K <sub>s</sub> > 3.66, which is equivalent to (R-K <sub>s</sub> ) <sub>Vega</sub> > 5. We conducted the clustering analysis for two magnitude-limited cases, K <sub>s</sub> < 20.3 (N = 363) and K <sub>s</sub> < 20.9 (N = 727), using two-point angular correlation represented by a single power-law function. By fixing a power-law (with 0.8), the correlation lengths of EROs with K <sub>s</sub> < 20.3 and K <sub>s</sub> < 20.9 are 9.10 ± 1.86 and 7.81 ± 1.21 h <sup>-1</sup> Mpc, respectively. We find that bias factors of EROs with K <sub>s</sub> < 20.3 and K <sub>s</sub> < 20.9 are 3.19 ± 0.59 and 2.83 ± 0.40, respectively, revealing that EROs reside in dark matter halos heavier than sim 1013 M⊙. To investigate possible descendants of EROs with K <sub>s</sub> < 20.9, we calculate how the bias for dark matter halos that host EROs evolves by accounting for mass growth of halos along the redshift. We find that halos hosting EROs evolve into halos hosting local massive galaxies with 2-7 L∗. It suggests that passive EROs with K <sub>s</sub> < 20.9 are likely to be progenitors of massive galaxies in the present universe. The comparison between passive EROs (pEROs) and star-forming EROs (sEROs) classified by near-infrared colors shows that pEROs seem to be connected with more massive local galaxies. By fitting spectral energy distributions (SEDs), we estimate active galactic nucleus (AGN) contribution for 68 sEROs which are selected in mid-IR bands. AGN contributions to the IR luminosity are less than 10\\\\\\\\\\\\\\\\% except for six sEROs. At least in the IR-selected sEROs, the contribution of AGN seems to be not significant.