Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published March 1, 2023 | Published
Journal Article Open

Testing the Radio-selection Method of Dual Active Galactic Nuclei in the Stripe 82 Field


We test the merger-induced dual active galactic nuclei (dAGNs) paradigm using a sample of 35 radio galaxy pairs from the Sloan Digital Sky Survey Stripe 82 field. Using Keck optical spectroscopy, we confirm 21 pairs have consistent redshifts, constituting kinematic pairs; the remaining 14 pairs are line-of-sight projections. We classify the optical spectral signatures via emission line ratios, equivalent widths, and excess of radio power above star formation predicted outputs. We find six galaxies are classified as LINERs and seven are AGN/starburst composites. Most of the LINERs are retired galaxies, while the composites likely have AGN contribution. All of the kinematic pairs exhibit radio power more than 10× above the level expected from just star formation, suggestive of a radio AGN contribution. We also analyze high-resolution (0.″3) imaging at 6 GHz from the NSF's Karl G. Jansky Very Large Array for 17 of the kinematic pairs. We find six pairs (two new, four previously known) host two separate radio cores, confirming their status as dAGNs. The remaining 11 pairs contain single AGNs, with most exhibiting prominent jets/lobes overlapping their companion. Our final census indicates a dAGN duty cycle slightly higher than predictions of purely stochastic fueling, although a larger sample (potentially culled from VLASS) is needed to fully address the dAGN fraction. We conclude that while dAGNs in the Stripe 82 field are rare, the merger process plays some role in their triggering and it facilitates low to moderate levels of accretion.

Additional Information

© 2023. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. The authors thank the anonymous referee for their comments, which improved the manuscript. The authors also thank Andrea Prestwich and Dylan Paré for helpful discussions. The scientific results reported in this article are based on observations made by the VLA. A.G. and H.F. acknowledge support from the National Science Foundation (NSF) grants AST-1614326 and AST-2103251. The NRAO is a facility of the NSF, operated under cooperative agreement by Associated Universities, Inc. In addition to the data included in the online-only journal, data is available upon reasonable request to the corresponding author.

Attached Files

Published - Gross_2023_ApJ_945_73.pdf


Files (35.6 MB)
Name Size Download all
35.6 MB Preview Download

Additional details

August 22, 2023
August 22, 2023