The DEEP2 Galaxy Redshift Survey: AEGIS Observations of a Dual AGN at z = 0.7

Abstract

We present evidence of a dual active galactic nucleus (AGN) within an early-type galaxy at z = 0.709 in the extended Groth strip. The galaxy lies on the red sequence, with absolute magnitude M_B = -21.0 (AB, with h = 0.7) and rest-frame color U - B = 1.38. Its optical spectrum shows strong, double-peaked [O III] emission lines and weak Hβ emission, with Seyfert-like line ratios. The two narrow peaks are separated by 630 km s^(-1) in velocity and arise from two distinct regions, spatially resolved in the DEIMOS spectrum, with a projected physical separation of 1.2 kpc. HST ACS imaging shows an early-type (E/S0) galaxy with hints of disturbed structure, consistent with the remnant of a dissipationless merger. Multiwavelength photometric information from the AEGIS consortium confirms the identification of a dust-obscured AGN in an early-type galaxy, with detections in X-ray, optical, infrared, and radio wave bands. These data are most readily explained as a single galaxy harboring two AGNs—the first such system to be observed in an otherwise typical early-type galaxy.