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Session 87 - Environments of QSOs and Radio Galaxies.
Oral session, Wednesday, January 17
Corte Real, Hilton
Molecular gas upper limits and rest-frame optical spectroscopy of a sample of 0.9 < z < 4 high redshift powerful radio galaxies (HzPRGs) are presented. The four best studied radio galaxies (3C 368, 4C 23.56, B2 0902+34, and 4C 41.17) have molecular gas masses comparable to or less than the most gas-rich, ultraluminous infrared galaxies (ULIGs) in the local (z \leq 0.3) Universe (i.e. M(H_2) < 2-3\times 10^10\ h^-2\ M_ødot;\ H_0 = 100h km s^-1 Mpc^-1 and q_0 = 0.5). HzPRGs have Seyfert II-like optical emission line spectra, indicative of photoinization by active galactic nuclei (AGNs). The galaxy 3C 22 is the only source in the sample with broad H\alpha wings, a clear indication that AGN light is escaping from the nuclear region of the host galaxy. These observations support growing evidence that AGNs, not stars, dominate the energetics of HzPRGs. We conclude that 0.9 < z < 4 HzPRGs as a class are simply more radio-luminous versions of radio galaxies in the local Universe, and that there is no evidence HzPRGs are primeval in nature.
