A Second Look at 12 Candidate Dual AGNs using BAYMAX
Abstract
We present an analysis of 12 optically selected dual AGN candidates at z < 0.34. Each candidate was originally identified via double-peaked [O III] λ5007 emission lines, and have received follow-up Chandra and HST observations. Because the X-ray data are low-count (<100 counts) with small separations (<1"), a robust analysis is necessary for classifying each source. Pairing long-slit [O III] observations with existing Chandra observations, we re-analyze the X-ray observations with BAYMAX to determine whether the X-ray emission from each system is more likely a single or dual point source. We find that 4 of the 12 sources are likely dual X-ray point source systems. We examine each point source's spectra via a Monte Carlo method that probabilistically identifies the likely origin of each photon. When doing so, we find that (i) the secondary X-ray point sources in 2 of the systems have LX<1040 erg s-1, such that we cannot rule out a non-AGN origin, (ii) one source has a secondary with LX>1040 erg s-1 but a spectrum that is too soft to definitively preclude being X-ray emitting diffuse gas that was photoionized by the primary AGN, and (iii) one system (SDSS J1126+2944) is a dual AGN. Additionally, using complementary HST observations, we analyze a sub-sample of systems that are visually identified as merging. Our results suggest that dual AGNs may preferentially reside in mergers with small separations, consistent with both simulations and observations.