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 component 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.

A possible sub-kiloparsec dual AGN buried behind the galaxy curtain / Severgnini P.; Braito V.; Cicone C.; Saracco P.; Vignali C.; Serafinelli R.; Della Ceca R.; Dotti M.; Cusano F.; Paris D.; Pruto G.; Zaino A.; Ballo L.; Landoni M.. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - STAMPA. - 646:(2021), pp. A153.1-A153.10. [10.1051/0004-6361/202039576]

A possible sub-kiloparsec dual AGN buried behind the galaxy curtain

Vignali C.
Membro del Collaboration Group
;
2021

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 component 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.
2021
A possible sub-kiloparsec dual AGN buried behind the galaxy curtain / Severgnini P.; Braito V.; Cicone C.; Saracco P.; Vignali C.; Serafinelli R.; Della Ceca R.; Dotti M.; Cusano F.; Paris D.; Pruto G.; Zaino A.; Ballo L.; Landoni M.. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - STAMPA. - 646:(2021), pp. A153.1-A153.10. [10.1051/0004-6361/202039576]
Severgnini P.; Braito V.; Cicone C.; Saracco P.; Vignali C.; Serafinelli R.; Della Ceca R.; Dotti M.; Cusano F.; Paris D.; Pruto G.; Zaino A.; Ballo L.; Landoni M.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/863269
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