Star formation rates in luminous quasars at 2 < z < 3

International audienceWe investigate the relation between star formation rates (dot{{M}}_s) and AGN properties in optically selected type 1 quasars at 2 ⊙ yr-1. Conversely, dot{{M}}_s increases with AGN luminosity, up to a maximum of ∼ 600 M⊙ yr-1, and with C IV FWHM. In context with previous results, this is consistent with a relation between dot{{M}}_s and black hole accretion rate (dot{{M}}_{bh}) existing in only parts of the z-dot{{M}}s-dot{{M}}_{bh} plane, dependent on the free gas fraction, the trigger for activity, and the processes that may quench star formation. The relations between dot{{M}}_s and both AGN luminosity and C IV FWHM are consistent with star formation rates in quasars scaling with black hole mass, though we cannot rule out a separate relation with black hole accretion rate. Star formation rates are observed to decline with increasing C IV equivalent width. This decline can be partially explained via the Baldwin effect, but may have an additional contribution from one or more of three factors; MI is not a linear tracer of L2500, the Baldwin effect changes form at high AGN luminosities, and high C IV EW values signpost a change in the relation between dot{{M}}_s and dot{{M}}_{bh}. Finally, there is no strong relation between dot{{M}}_s and Eddington ratio, or the asymmetry of the C IV line. The former suggests that star formation rates do not scale with how efficiently the black hole is accreting, while the latter is consistent with C IV asymmetries arising from orientation effects