Building a large sample of kiloparsec (kpc)-scale dual active galactic nuclei (AGNs) amongst merging galaxies is of vital importance to understand the co-evolution between host galaxies and their central super massive black holes (SMBHs). Doing so, with just such a sample, we have developed an innovative method of systematically searching and identifying dual AGNs of amongst kpc scale merging galaxies and selected 222 candidates at redshifts < 0.25. All the selected candidates have FIRST radio detection and at least one of two cores previously revealed as AGN spectroscopically. In Section 3, We report the first results from A SysTematic seaRch fOr Dual Agns in meRgINg Galaxies (ASTRO-DARING), which consist of spatially resolved long-slit spectroscopic observations of 41 targets selected from our merging galaxies sample, using the Yunnan Faint Object Spectrograph and Camera (YFOSC). Of these 16 are likely dual AGNs and 15 are newly identified. The efficiency of ASTRO-DARING is thus nearly 40 %. In Section 4, as a series systematically searching dual AGN amongst merging galaxies, we present the results of 20 dual AGNs found by using the SDSS fiber spectra. 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 33 per cent (20/61), comparable to our former results based on the long-slit spectroscopy. Interestingly, 2 of the 20 dual AGNs (i.e., J0955 + 3954 and J1338 + 4816) show two prominent cores in radio images and their radio powers show they as the radio-excess AGNs. With this method, we plan to build the first even sample of more than 50 dual AGNs constructed using a consistent approach. 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 is of vital importance to study the dual AGN physics and the co-evolution between the super massive black holes and their host galaxies.
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