Searching for Dual AGN in Galaxies with Double-Peaked Emission Line
  Spectra using Radio Observations
  Supermassive black hole (SMBH) binaries form due to galaxy mergers and minor
accretion events. When the SMBHs are accreting, they form dual or binary AGN
and can give rise to double-peaked emission lines in the optical spectra of the
merger remnant. The double-peaked emission lines could also be due to jet-ISM
interaction or rotating disks. One of the best ways to confirm dual/binary AGN
in double-peaked AGN (DPAGN) is by using high resolution radio observations. We
have observed a sample of 20 DPAGN at two or more frequencies using the Karl G.
Jansky Very Large Array (VLA), of which one source is already published and the
remaining 19 are presented in this paper. We have detected dual radio
structures at separation of $\lesssim$ 10 kpc in three of our sample galaxies.
Using the spectral index maps and optical spectra of the sources, we have
confirmed that one of them is a dual AGN (DAGN), while the other two can be
dual AGN or AGN+ star-forming nuclei pairs. Of the remaining sources, one has a
clear core-jet structure and another source could be a core-jet structure or a
DAGN. The remaining 13 sources are single cores while one source is not
detected at any frequency. We find that for our dual AGN detection, the DPAGN
emission lines do not originate from the dual/binary AGN. Instead, they could
be due to outflows or jets. Hence, we conclude that DPAGN identified in low
resolution SDSS spectra are not good indicators of dual/binary AGN. On the
other hand, closely interacting galaxies or merger remnants are good candidates
for detecting dual/binary AGN.
