In:
Astronomy & Astrophysics, EDP Sciences, Vol. 646 ( 2021-02), p. A153-
Abstract:
Although thousands of galaxy mergers are known, only a handful of sub-kiloparsec-scale supermassive black hole (SMBH) pairs have been confirmed so far, leaving a huge gap between the observed and predicted numbers of such objects. In this work, we present a detailed analysis of the Sloan Digital Sky Survey optical spectrum and of near-infrared (NIR) diffraction limited imaging of SDSS J1431+4358 . This object is a local radio-quiet type 2 active galactic nucleus (AGN) previously selected as a double AGN candidate on the basis of the double-peaked [OIII] emission line. The NIR adaptive optics-assisted observations were obtained at the Large Binocular Telescope with the LUCI+FLAO camera. We found that most of the prominent optical emission lines are characterized by a double-peaked profile, mainly produced by AGN photoionization. Our spectroscopical analysis disfavors the hypothesis that the double-peaked emission lines in the source are the signatures of outflow kinematics, leaving open the possibility that we are detecting either the rotation of a single narrow-line region or the presence of two SMBHs orbiting around a common central potential. The latter scenario is further supported by the high-spatial resolution NIR imaging: after subtracting the dominant contribution of the stellar bulge componen t in the host galaxy, we detect two faint nuclear sources at r 〈 0.5 kpc projected separation. Interestingly, the two sources have a position angle consistent with that defined by the two regions where the [OIII] double peaks most likely originate. Aside from the discovery of a promising sub-kiloparsec scale dual AGN, our analysis shows the importance of an appropriate host galaxy subtraction in order to achieve a reliable estimate of the incidence of dual AGNs at small projected separations.
Type of Medium:
Online Resource
ISSN:
0004-6361
,
1432-0746
DOI:
10.1051/0004-6361/202039576
Language:
English
Publisher:
EDP Sciences
Publication Date:
2021
detail.hit.zdb_id:
1458466-9
SSG:
16,12
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