Morphological evolution in high-redshift radio galaxies and the formation of giant elliptical galaxies

摘要

We present deep near-infrared images of high-redshift radio galaxies(HzRGs) obtained with the near- infrared camera(NIRC) on the Keck I telescope. In most case, the near-IR data sample rest wave- lengths that are free of contamination from strong emission lines and at λ_rest > 4000 A, where older stellar populations, if present, might dominate the observed flux. At z > 3, the rest-frame optical mor- phologies generally have faint, large-scale( ～50 kpc) emission surrounding multiple, ～10 kpc com- ponents. The brightest of these components are often aligned with the radio structures.