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Optical and JWST Mid-IR Emission Line Diagnostics for Simultaneous IMBH and Stellar Excitation in z ∼ 0 Dwarf Galaxies*
Abstract Current observational facilities have yet to conclusively detect 10 3 –10 4 M ⊙ intermediate-mass black holes (IMBHs) that fill in the evolutionary gap between seed black holes in the early universe and z ∼ 0 supermassive black holes. Dwarf galaxies present an opportunity to reveal active IMBHs amidst persistent star formation. We introduce photoionization simulations tailored to address key physical uncertainties: coincident versus noncoincident mixing of IMBH and starlight excitation, open versus closed geometries of surrounding gas clouds, and different shapes of the spectral energy distribution of active galactic nuclei (AGN). We examine possible AGN emission line diagnostics in the optical and mid-IR, and find that the diagnostics are often degenerate with respect to the investigated physical uncertainties. In spite of these setbacks, and in contrast to recent work, we are able to show that [O iii ]/H β typically remains bright for dwarf AGN powered by IMBHs down to 10 3 M ⊙ . Dwarf AGN are predicted to have inconsistent star-forming and Seyfert/LINER classifications using the most common optical diagnostics. In the mid-IR, [O iv ] 25.9 μ m and [Ar ii ] 6.98 μ m are less sensitive to physical uncertainties than are optical diagnostics. more »
Authors:
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Award ID(s):
Publication Date:
NSF-PAR ID:
10333821
Journal Name:
The Astrophysical Journal
Volume:
927
Issue:
2
Page Range or eLocation-ID:
165
ISSN:
0004-637X
National Science Foundation
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1. Abstract

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3. ABSTRACT

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4. Abstract

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5. Abstract

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