Molecular gas in lensed z >2 quasar host galaxies and the star formation law for galaxies with luminous active galactic nuclei.
Abstract (from CDS):
We report the detection of luminous CO(J = 2 ⟶ 1), CO(J = 3 ⟶ 2), and CO(J = 4 ⟶ 3) emission in the strongly lensed high-redshift quasars B1938+666 (z = 2.059), HE 0230-2130 (z = 2.166), HE 1104-1805 (z = 2.322), and B1359+154 (z = 3.240), using the Combined Array for Research in Millimeter-wave Astronomy. B1938+666 was identified in a "blind" CO redshift search, demonstrating the feasibility of such investigations with millimeter interferometers. These galaxies are lensing-amplified by factors of µL≃ 11-170, and thus allow us to probe the molecular gas in intrinsically fainter galaxies than currently possible without the aid of gravitational lensing. We report lensing-corrected intrinsic CO line luminosities of L'CO= 0.65-21x109 K km/s pc2, translating to H2 masses of M(H2) = 0.52-17x109 (αCO/0.8) M☉. To investigate whether or not the active galactic nucleus (AGN) in luminous quasars substantially contributes to LFIR, we study the L'CO-L FIR relation for quasars relative to galaxies without a luminous AGN as a function of redshift. We find no substantial differences between submillimeter galaxies and high-z quasars, but marginal evidence for an excess in LFIR in nearby low-LFIR AGN galaxies. This may suggest that an AGN contribution to LFIR is significant in systems with relatively low gas and dust content, but only minor in the most far-infrared-luminous galaxies (in which LFIR is dominated by star formation).
cosmology: observations - galaxies: active - galaxies: formation - galaxies: high-redshift - galaxies: starburst - radio lines: galaxies