Speaker
Description
Galactic-scale outflows driven by active galactic nuclei (AGNs) have been invoked to explain the quenching of star formation in massive galaxies. Large statistical outflow samples are required to study to fully understand their impact on galaxy evolution. The most traditional technique to distinguish the outflowing gas from non-outflowing gas is to detect the blueshifted-wings in the absorption and/or emission-line profiles as they represent the outflowing motion of the gas. However, this technique requires spectra with high signal-to-noise (S/N) ratio to decompose outflowing components. Over past decades, many researchers have developed a new technique to obtain a significant number of galaxies with large-scale outflow by reconstructing images of [O III]$\lambda\lambda4949, 5007$ emission using narrowband and/or broadband images. Nevertheless, the gas kinematics of the outflows selected from this technique are less studied. To answer this question, we compare the selection efficiency of the galactic-scale outflows from broadband images and spectroscopy. We apply both of the outflow selection techniques to 165 local galaxies ($z\sim0.1$) observed by the Mapping Nearby Galaxies at APO (MaNGA) survey, the latest integral-field spectroscopic survey of the Sloan Digital Sky Survey (SDSS). Fourty-seven ($\sim28\%$) galaxies are classified as AGNs based on line diagnostic diagrams and multi-wavelength observations. We construct [O III] images using the SDSS broadband images together with a continuum subtraction of the galactic continuum. We find that the area of [O III] emission-line regions are positively correlated with the outflow velocities, as traced by the 98\% extent of Na ID $\lambda\lambda$5890,5896 absorption lines with a power-law slope of 0.64$\pm$0.16. We discuss the selection efficiency and applications of the broadband images to study the AGN feedback with large statistical samples.
