Skip to main content


Author(s): Barrows, R Scott; Comerford, Julia M; Greene, Jenny E.; Pooley, David

To refer to this page use:
Abstract: We present a sample of 18 optically selected and X-ray-detected spatially offset active galactic nuclei (AGNs) from the Sloan Digital Sky Survey (SDSS). In nine systems, the X-ray active galactic nucleus (AGN) is spatially offset from the galactic stellar core that is located within the 3 ‘’ diameter SDSS spectroscopic fiber. In 11. systems, the X-ray AGN is spatially offset from a stellar core that is located outside the fiber, with an overlap of two. To build the sample, we cross-matched Type II AGNs selected from the SDSS galaxy catalog with archival Chandra imaging and employed our custom astrometric and registration procedure. The projected angular (physical) offsets span a range of 0.” 6 (0.8 kpc) to 17.” 4 (19.4 kpc), with a median value of 2.” 7 (4.6 kpc). The offset nature of an AGN is an unambiguous signature of a galaxy merger, and these systems can be used to study the properties of AGNs in galaxy mergers without the biases introduced by morphological merger selection techniques. In this paper (Paper I), we use our sample to assess the kinematics of AGN photoionized gas in galaxy mergers. We find that spectroscopic offset AGN selection may be up to 89(-16)(+7) % incomplete due to small projected velocity offsets. We also find that the magnitude of the velocity offsets are generally larger than expected if our spatial selection introduces a bias toward face-on orbits, suggesting the presence of complex kinematics in the emission line gas of AGNs in galaxy mergers.
Publication Date: 20-Sep-2016
Electronic Publication Date: 20-Sep-2016
Citation: Barrows, R Scott, Comerford, Julia M, Greene, Jenny E, Pooley, David. (2016). SPATIALLY OFFSET ACTIVE GALACTIC NUCLEI. I. SELECTION AND SPECTROSCOPIC PROPERTIES. ASTROPHYSICAL JOURNAL, 829 (10.3847/0004-637X/829/1/37
DOI: doi:10.3847/0004-637X/829/1/37
ISSN: 0004-637X
EISSN: 1538-4357
Related Item:
Type of Material: Journal Article
Journal/Proceeding Title: ASTROPHYSICAL JOURNAL
Version: Final published version. Article is made available in OAR by the publisher's permission or policy.

Items in OAR@Princeton are protected by copyright, with all rights reserved, unless otherwise indicated.