Abstract

Aims. Our aim is to search for and characterize inflows and outflows of molecular gas in four ultraluminous infrared galaxies (ULIRGs; L-IR > 10(12) L-circle dot) at z similar to 0.2-0.3 and one distant quasi-stellar object (QSO) at z = 6.13. Methods. We used Herschel/PACS and ALMA Band 7 observations of the hydroxyl molecule (OH) line at rest-frame wavelength 119 mu m, which in absorption can provide unambiguous evidence of inflows or outflows of molecular gas in nuclear regions of galaxies. Our study contributes to doubling the number of OH 119 mu m observations of luminous systems at z similar to 0.2-0.3, and pushes the search for molecular outflows based on the OH 119 mu m transition to z similar to 6. Results. We detect OH 119 mu m high-velocity absorption wings in three of the four ULIRGs. In two cases, IRAS F20036-1547 and IRAS F13352+6402, the blueshifted absorption profiles indicate the presence of powerful and fast (similar to 200-500 km s(-1)) molecular gas outflows. Consistent with an inside-out quenching scenario, these outflows are depleting the central reservoir of star-forming molecular gas at a rate similar to that of intense star formation activity. For the starburst-dominated system IRAS 10091+4704, we detect an inverted P Cygni profile that is unique among ULIRGs and indicates the presence of a fast (similar to 400 km s(-1)) inflow of molecular gas at a rate of similar to 100 M-circle dot yr(-1) towards the central region. Finally, we tentatively detect (similar to 3 sigma) the OH 119 mu m doublet in absorption in the z = 6.13 QSO ULAS J131911+095051. The OH 119 mu m feature is blueshifted with a median velocity that suggests the presence of a molecular outflow, although characterized by a modest molecular mass loss rate of similar to 200 M-circle dot yr(-1). This value is comparable to the small mass outflow rates found in the stacking of the [C II] spectra of other z similar to 6 QSOs and suggests that ejective feedback in this phase of the evolution of ULAS J131911+095051 has subsided.