Fast Molecular Outflows in Luminous Galaxy Mergers: Evidence for Quasar Feedback from Herschel

We report the results from a systematic search for molecular (OH 119 μm) outflows with Herschel-PACS in a sample of 43 nearby (z < 0.3) galaxy mergers, mostly ultraluminous infrared galaxies (ULIRGs) and QSOs. We find that the character of the OH feature (strength of the absorption relative to the emission) correlates with that of the 9.7-μm silicate feature, a measure of obscuration in ULIRGs. Unambiguous evidence for molecular outflows, based on the detection of OH absorption profiles with median velocities more blueshifted than −50 km Department of Astronomy, University of Maryland, College Park, MD 20742, USA; [email protected], [email protected], [email protected] Joint Space-Science Institute, University of Maryland, College Park, MD 20742, USA Max-Planck-Institute for Extraterrestrial Physics (MPE), Giessenbachstrae 1, 85748 Garching, Germany Naval Research Laboratory, Remote Sensing Division, 4555 Overlook Ave SW, Washington, DC 20375, USA Universidad de Alcalá, Departamento de F́ısica y Matemáticas, Campus Universitario, E-28871 Alcalá de Henares, Madrid, Spain Tel Aviv University, Sackler School of Physics & Astronomy, Ramat Aviv 69978, Israel Department of Astronomy, California Institute of Technology, Pasadena, California, 91125 USA Department of Astrophysics, Oxford University, Oxford OX1 3RH, UK Department of Physics, Rhodes College, Memphis, TN 38112, USA Cavendish Laboratory, University of Cambridge, 19 J.J. Thomson Ave., Cambridge, CB3 0HE, UK Kavli Institute for Cosmology, Madingley Road, Cambridge, CB3 0HA, UK Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA 1 Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.