Magellan Spectroscopy of Active Galactic Nuclei in Low-mass Galaxies: Scaling Relations and a Triple-peaked Active Galactic Nucleus

In this work, we aim to further populate the low-mass regime of black hole (BH) scaling relations to better understand the formation and growth mechanisms of central supermassive BHs. We target six galaxies that have been previously identified as hosting active galactic nuclei (AGNs) based on optica...

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Main Authors: Megan R. Sturm, Amy E. Reines, Jenny Greene, Sheyda Salehirad
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/aded92
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author Megan R. Sturm
Amy E. Reines
Jenny Greene
Sheyda Salehirad
author_facet Megan R. Sturm
Amy E. Reines
Jenny Greene
Sheyda Salehirad
author_sort Megan R. Sturm
collection DOAJ
description In this work, we aim to further populate the low-mass regime of black hole (BH) scaling relations to better understand the formation and growth mechanisms of central supermassive BHs. We target six galaxies that have been previously identified as hosting active galactic nuclei (AGNs) based on optical spectroscopy from the Galaxy and Mass Assembly survey or the Sloan Digital Sky Survey with stellar masses reported to be M _⋆  < 5 × 10 ^9 M _⊙ . Using follow-up optical spectroscopy from the Magellan Echellette Spectrograph, we extract galaxy velocity dispersions ( σ _⋆ ) and estimate virial BH masses from broad H α emission. We find that the galaxies in our sample do not deviate significantly from either the M _BH − σ _* or M _BH − M _* scaling relations defined by higher-mass galaxies. Additionally, we identify one galaxy with triple-peaked [S II ], [N II ], H α , and H β emission lines. This spectral shape is not shared by [O III ] and, in fact, the [O III ] line appears to have distinct kinematics from the other emission lines. Incorporating the spatial distribution of the various emission lines, we find that the galaxy spectrum is consistent with a prominent central AGN driving an outflow, surrounded by an extended ring/disk of gas predominantly ionized by shocks and/or star formation. This work has implications for the demographics of BHs in low-mass galaxies and the role of AGN feedback.
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spelling doaj-art-d9043e3526ed4882a56fb240aed07efe2025-08-20T03:41:15ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01989213610.3847/1538-4357/aded92Magellan Spectroscopy of Active Galactic Nuclei in Low-mass Galaxies: Scaling Relations and a Triple-peaked Active Galactic NucleusMegan R. Sturm0https://orcid.org/0000-0003-1055-1888Amy E. Reines1https://orcid.org/0000-0001-7158-614XJenny Greene2https://orcid.org/0000-0002-5612-3427Sheyda Salehirad3https://orcid.org/0000-0002-4587-1905Department of Physics, Montana State University , Bozeman, MT 59717, USADepartment of Physics, Montana State University , Bozeman, MT 59717, USADepartment of Astrophysical Sciences, Princeton University , Princeton, NJ 08544, USADepartment of Physics, Montana State University , Bozeman, MT 59717, USAIn this work, we aim to further populate the low-mass regime of black hole (BH) scaling relations to better understand the formation and growth mechanisms of central supermassive BHs. We target six galaxies that have been previously identified as hosting active galactic nuclei (AGNs) based on optical spectroscopy from the Galaxy and Mass Assembly survey or the Sloan Digital Sky Survey with stellar masses reported to be M _⋆  < 5 × 10 ^9 M _⊙ . Using follow-up optical spectroscopy from the Magellan Echellette Spectrograph, we extract galaxy velocity dispersions ( σ _⋆ ) and estimate virial BH masses from broad H α emission. We find that the galaxies in our sample do not deviate significantly from either the M _BH − σ _* or M _BH − M _* scaling relations defined by higher-mass galaxies. Additionally, we identify one galaxy with triple-peaked [S II ], [N II ], H α , and H β emission lines. This spectral shape is not shared by [O III ] and, in fact, the [O III ] line appears to have distinct kinematics from the other emission lines. Incorporating the spatial distribution of the various emission lines, we find that the galaxy spectrum is consistent with a prominent central AGN driving an outflow, surrounded by an extended ring/disk of gas predominantly ionized by shocks and/or star formation. This work has implications for the demographics of BHs in low-mass galaxies and the role of AGN feedback.https://doi.org/10.3847/1538-4357/aded92Active galaxiesScaling relationsGalaxy evolution
spellingShingle Megan R. Sturm
Amy E. Reines
Jenny Greene
Sheyda Salehirad
Magellan Spectroscopy of Active Galactic Nuclei in Low-mass Galaxies: Scaling Relations and a Triple-peaked Active Galactic Nucleus
The Astrophysical Journal
Active galaxies
Scaling relations
Galaxy evolution
title Magellan Spectroscopy of Active Galactic Nuclei in Low-mass Galaxies: Scaling Relations and a Triple-peaked Active Galactic Nucleus
title_full Magellan Spectroscopy of Active Galactic Nuclei in Low-mass Galaxies: Scaling Relations and a Triple-peaked Active Galactic Nucleus
title_fullStr Magellan Spectroscopy of Active Galactic Nuclei in Low-mass Galaxies: Scaling Relations and a Triple-peaked Active Galactic Nucleus
title_full_unstemmed Magellan Spectroscopy of Active Galactic Nuclei in Low-mass Galaxies: Scaling Relations and a Triple-peaked Active Galactic Nucleus
title_short Magellan Spectroscopy of Active Galactic Nuclei in Low-mass Galaxies: Scaling Relations and a Triple-peaked Active Galactic Nucleus
title_sort magellan spectroscopy of active galactic nuclei in low mass galaxies scaling relations and a triple peaked active galactic nucleus
topic Active galaxies
Scaling relations
Galaxy evolution
url https://doi.org/10.3847/1538-4357/aded92
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