Infrared-Selected Active Galactic Nuclei in the Kepler Fields

TL;DR

This study identified and confirmed infrared-selected active galactic nuclei (AGN) in the Kepler fields using multiple spectroscopic observations, demonstrating high reliability and consistency with other AGN identification methods.

Contribution

The paper presents a validation of infrared selection techniques for AGN in the Kepler fields through extensive spectroscopic follow-up, confirming their effectiveness and reliability.

Findings

75% overall confirmation rate for AGN candidates

High reliability (87%-96%) for main selection methods

Spectral energy distributions consistent with literature AGN populations

Abstract

We utilized the Edelson and Malkan (2012) and Stern et al. (2012) selection techniques and other methods to identify AGN candidates that were monitored during the Kepler prime and K2 missions. Subsequent to those observations, we obtained 125 long-slit optical spectra with the Lick 3-m telescope, 58 spectra with the Palomar 5-m telescope, and three with the Keck 10-m telescope to test these identifications. Of these 186 AGN candidates, 105 were confirmed as Type 1 AGN and 35 as Type 2 AGN, while the remaining 46 were found to have other identifications (e.g., stars and normal galaxies). This indicated an overall reliability of about 75%, while the two main methods had much higher reliability, 87%-96%. The spectra indicated redshifts out to z = 3.4. Then, we examined the AGN sample properties through the Baldwin, Phillips & Terlevich diagram and compared the AGN's spectral energy distributions (SEDs) with those from the literature. We found that our sample yielded the same AGN population as those identified through other methods, such as optical spectroscopy.