VLA detects CO(1–0) emission in the z = 3.65 quasar SDSS J160705+533558

Abstract

We present CO(1–0) observations of the high-redshift quasar SDSS J160705+533558 (z = 3.653) using the Karl G. Jansky Very Large Array (VLA). We detect CO emission associated with the quasar and at ∼16.8 kpc projected distance from it, separated by ∼800 km s−1 in velocity. The total molecular gas mass of this system is ∼5 × 1010 M⊙. By comparing our CO detections with previous submillimetre (submm) observations of the source, an offset between the different emission components is revealed: the peak of the submm emission is offset from the quasar and from the CO companion detected in our VLA data. To explain our findings, we propose a scenario similar to that for the Antennae galaxies: SDSS J160705+533558 might be a merger system in which the quasar and the CO companion are the merging galaxies, whose interaction resulted in the formation of a dusty, star-forming overlap region between the galaxies that is dominant at the submm wavelengths.