A SysTematic seaRch fOr Dual Agns in meRgINg Galaxies (ASTRO-DARING)
  III: results from the SDSS spectroscopic surveys
  As the third installment in a series systematically searching dual active
galactic nuclei (AGN) amongst merging galaxies, we present the results of 20
dual AGNs found by using the SDSS fiber spectra. To reduce the flux
contamination from both the fiber aperture and seeing effects, the angular
separation of two cores in our merging galaxy pairs sample is restricted at
least larger than 3 arcsec. By careful analysis of the emission lines, 20 dual
AGNs are identified from 61 merging galaxies with their two cores both observed
by the SDSS spectroscopic surveys. 15 of them are identified for the first
time. The identification efficiency is about 32.79$\%$ (20/61), comparable to
our former results (16 dual AGNs identified from 41 merging galaxies) based on
the long-slit spectroscopy. Interestingly, two of the 20 dual AGNs show two
prominent cores in radio images and their radio powers show they as the
radio-excess AGNs. So far, 31 dual AGNs are found by our project and this is
the current largest dual AGN sample, ever constructed with a consistent
approach. This sample, together with more candidates from ongoing observations,
is of vital importance to study the AGN physics and the coevolution between the
supermassive black holes and their host galaxies.
