The Morphology of Dwarf Galaxies Hosting Variable Active Galactic Nuclei

Fuente: arXiv
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Autores principales: Kimbro, Erin, Baldassare, Vivienne, Worthey, Guy, Geha, Marla, Greene, Jenny
Formato: Preprint
Publicado: 2025
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author Kimbro, Erin
Baldassare, Vivienne
Worthey, Guy
Geha, Marla
Greene, Jenny
author_facet Kimbro, Erin
Baldassare, Vivienne
Worthey, Guy
Geha, Marla
Greene, Jenny
contents We analyze Hubble Space Telescope (HST) optical imaging of eight low-mass galaxies hosting active galactic nuclei (AGN) identified via their photometric variability in \cite{baldassare_search_2020}. We use GALFIT to model the 2D galaxy light profiles, and find a diversity of morphologies. The galaxies with regular morphologies are best fit with pseudo-bulges and disks, rather than classical bulges. We estimate black hole masses using scaling relations and find black hole masses of 10$^{3.7-6.6}$ M$_\odot$. We compare this sample to dwarf galaxies with AGN selected via optical spectroscopy. On average, the variable host galaxies have lower mass black holes. We analyze the brightest point source in each galaxy and find their properties are not entirely consistent with star clusters, indicating that they are likely AGN. These point sources are found to have lower luminosities than spectroscopically selected dwarf AGN, but brighter than the point sources in dwarf galaxies not identified as AGN. Our detailed imaging analysis shows that variability selection has the potential to find lower mass black holes and lower luminosity AGN than optical spectroscopy. These active dwarfs may have been missed by spectroscopic searches due to star formation dilution or low gas content.
format Preprint
id arxiv_https___arxiv_org_abs_2502_02751
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Morphology of Dwarf Galaxies Hosting Variable Active Galactic Nuclei
Kimbro, Erin
Baldassare, Vivienne
Worthey, Guy
Geha, Marla
Greene, Jenny
Astrophysics of Galaxies
We analyze Hubble Space Telescope (HST) optical imaging of eight low-mass galaxies hosting active galactic nuclei (AGN) identified via their photometric variability in \cite{baldassare_search_2020}. We use GALFIT to model the 2D galaxy light profiles, and find a diversity of morphologies. The galaxies with regular morphologies are best fit with pseudo-bulges and disks, rather than classical bulges. We estimate black hole masses using scaling relations and find black hole masses of 10$^{3.7-6.6}$ M$_\odot$. We compare this sample to dwarf galaxies with AGN selected via optical spectroscopy. On average, the variable host galaxies have lower mass black holes. We analyze the brightest point source in each galaxy and find their properties are not entirely consistent with star clusters, indicating that they are likely AGN. These point sources are found to have lower luminosities than spectroscopically selected dwarf AGN, but brighter than the point sources in dwarf galaxies not identified as AGN. Our detailed imaging analysis shows that variability selection has the potential to find lower mass black holes and lower luminosity AGN than optical spectroscopy. These active dwarfs may have been missed by spectroscopic searches due to star formation dilution or low gas content.
title The Morphology of Dwarf Galaxies Hosting Variable Active Galactic Nuclei
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2502.02751