NuSTAR Resolves the First Dual AGN above 10 keV in SWIFT J2028.5+2543
Abstract
We have discovered heavy obscuration in the dual active galactic nucleus (AGN) in the Swift/Burst Alert Telescope (BAT) source SWIFT J2028.5+2543 using Nuclear Spectroscopic Telescope Array (NuSTAR). While an early XMM-Newton study suggested the emission was mainly from NGC 6921, the superior spatial resolution of NuSTAR above 10 keV resolves the Swift/BAT emission into two sources associated with the nearby galaxies MCG +04-48-002 and NGC 6921 (z = 0.014) with a projected separation of 25.3 kpc (91"). NuSTAR's sensitivity above 10 keV finds both are heavily obscured to Compton-thick levels (N H=(1-2)x10^24 cm-2) and contribute equally to the BAT detection ({L}10-50 {keV}{{int}}= 6x10^42 erg s-1). The observed luminosity of both sources is severely diminished in the 2-10 keV band, illustrating the importance of >10 keV surveys like those with NuSTAR and Swift/BAT. Compared to archival X-ray data, MCG +04-48-002 shows significant variability (>3) between observations. Despite being bright X-ray AGNs, they are difficult to detect using optical emission-line diagnostics because MCG +04-48-002 is identified as a starburst/composite because of the high rates of star formation from a luminous infrared galaxy while NGC 6921 is only classified as a LINER using line detection limits. SWIFT J2028.5+2543 is the first dual AGN resolved above 10 keV and is the second most heavily obscured dual AGN discovered to date in the X-rays other than NGC 6240.
Keywords
Cite
@article{arxiv.1708.06762,
title = {NuSTAR Resolves the First Dual AGN above 10 keV in SWIFT J2028.5+2543},
author = {Michael J. Koss and Ana Glidden and Mislav Balokovic and Daniel Stern and Isabella Lamperti and Roberto Assef and Franz Bauer and David Ballantyne and Steven E. Boggs and William W. Craig and Dancan Farrah and Felix Furst and Poshak Gandhi and Neil Gehrels and Charles J. Hailey and Fiona A. Harrison and Craig Markwardt and Alberto Masini and Claudio Ricci and Ezequiel Treister and Dominic J. Walton and William W. Zhang},
journal= {arXiv preprint arXiv:1708.06762},
year = {2017}
}
Comments
Published in ApJ, 7 pages, 4 figures