2006/06/21 by N. P. H. Nesvadba, M. D. Lehnert, F. Eisenhauer +4 · 22 citations
Physics and Astronomy · #Active galactic nucleus #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Cosmology and Gravitation Theories #Dark matter #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Gravitational potential #Luminous infrared galaxy #Outflow #Physics #Radio galaxy #Redshift #astro-ph
paper · pdf · doi:10.1086/507266
published as Astrophys.J.650:693-705,2006 · Accepted for publication in the Astrophysical Journal
arxiv created 2006/06/21 · openalex publication_date 2006/10/18 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
To explain the properties of the most massive low-redshift galaxies and the shape of their mass function, recent models of galaxy evolution include strong AGN feedback to complement starburst-driven feedback in massive galaxies. Using the near-infrared integral-field spectrograph SPIFFI on the VLT, we searched for direct evidence for such feedback in the optical emission line gas around the z = 2.16 powerful radio galaxy MRC 1138-262, likely a massive galaxy in formation. The kiloparsec-scale kinematics, with FWHMs and relative velocities ≲2400 km s -1 and nearly spherical spatial distribution, do not resemble large-scale gravitational motion or starburst-driven winds. Order-of-magnitude timescale and energy arguments favor the AGN as the only plausible candidate to accelerate the gas, with a total energy injection of a few × 10 60 ergs or more, necessary to power the outflow, and relatively efficient coupling between radio jet and ISM. Observed outflow properties are in gross agreement with the models and suggest that AGN winds might have a cosmological significance that is similar to, or perhaps larger than, starburst-driven winds if MRC 1138-262 is indeed archetypal. Moreover, the outflow has the potential to remove significant gas fractions (≲50%) from a > L * galaxy within a few tens to 100 Myr, fast enough to preserve the observed [α/Fe] overabundance in massive galaxies at low redshift. Using simple arguments, it appears that feedback like that observed in MRC 1138-262 may have sufficient energy to inhibit material from infalling into the dark matter halo and thus regulate galaxy growth as required in some recent models of hierarchical structure formation.