Namrata Roy: Feeding and feedback via large scale AGN driven winds in nearby elliptical galaxies

Active galactic nuclei (AGN) driven feedback has been proposed to be one of the most efficient ways to quench star formation and help maintain quiescence in massive galaxies. However direct evidence of feedback in typical quiescent galaxy populations has been restricted to only a handful of sources. I will present evidence from a series of papers that large-scale winds in a new (and relatively common) class of early-type galaxy, known as ‘red geysers’, may represent maintenance mode feedback in action. I will show that red geysers host low luminosity radio mode AGNs with a wide range of radio morphologies: from double-lobed radio galaxy-like jets to compact and slightly extended features. The average radio sizes vary between 5 - 30 kpc, closely resembling the ‘FR0’ radio galaxies. Detailed ionized gas kinematics. from optical long-slit spectroscopy (Keck ESI) together with integral field unit data (SDSS IV- MaNGA survey), are consistent with geometric projections through an outflowing broad conical wind oriented at an angle to the line of sight. I will finally show that a large fraction of red geysers, especially the radio-bright ones, host significant amounts of cool neutral gas in the interstellar medium that show distinct signatures of inflow. This inflowing gas might fuel the radio-mode AGNs in the center which, in turn, can trigger the outflowing wind visible in the ionized phase. Our sample consists of completely quenched galaxies with very little star formation rate (log SFR < 0.01 Msun/yr). We conclude that red geysers support a feedback picture in which episodic AGN activity drives large-scale but relatively weak ionized winds in early-type galaxies. A critical next step is to use cosmological hydrodynamical simulations to deepen our theoretical understanding of these winds and their impact on quenching. Our ongoing work aims to bridge sophisticated high-resolution simulations with upcoming big data sets in order to better constrain the physics of feedback and outflows from early dwarf galaxies to today’s large ellipticals.