2025ApJ...985..107S -
Astrophys. J., 985, 107 (2025/May-3)
Possibility of Using 3.3 μm Polycyclic Aromatic Hydrocarbon Luminosity as a Molecular Gas Mass Estimator.
SHIM H., BAEK J., KIM D., KIM M., SONG H., LIM G., CHO J., JEONG H., JEONG Y., KANG Y.-E., LEE D., PARK J., SEO E., SONG J. and YEO B.
Abstract (from CDS):
We present CO(1-0) observations of 50 star-forming galaxies at 0.01 < z < 0.35, for which 3.3 μm polycyclic aromatic hydrocarbon (PAH) emission flux or its upper limit is available. A scaling relation between 3.3 μm PAH luminosity and CO(1-0) luminosity is established covering ∼2 orders of magnitude in total IR luminosity and CO luminosity, with a scatter of ∼0.23 dex: ${\mathrm{log}}\,{L}_{3.3}/{L}_{\odot }$ = $(1.00\pm 0.07)\times {\rm{log}}\,{L}_{{\rm{CO}}(1-0)}^{{\prime} }/({\rm{K}}\,{\rm{km}}\,{{\rm{s}}}^{-1}\,{{\rm{pc}}}^{2})$ +(-1.10 ± 0.70). The slope is near unity, allowing the use of a single value of $\langle {\rm{log}}\,({L}_{3.3}/{L}_{{\rm{CO}}(1-0)}^{{\prime} })\rangle $ =-1.09 ± 0.36 [L⊙/(K km s–1 pc2)] in the conversion between 3.3 μm PAH and CO luminosities. The variation in the ${L}_{3.3}/{L}_{{\rm{CO}}}^{{\prime} }$ ratio is not dependent on the galaxy properties, including total IR luminosity, stellar mass, and star formation rate excess. The total gas mass, estimated using the dust-to-gas ratio and dust mass, is correlated with 3.3 μm PAH luminosity, in line with the prescription using αCO = 0.8-4.5 covering both normal star-forming galaxies and starburst galaxies. Active galactic nucleus (AGN)-dominated galaxies tend to have a lower ${L}_{3.3}/{L}_{{\rm{CO}}}^{{\prime} }$ than non-AGN galaxies, which needs to be investigated further with an increased sample size. The established L3.3-${L}_{{\rm{CO}}}^{{\prime} }$ correlation is expected to be applicable to wide-field near-infrared spectrophotometric surveys that allow the detection of 3.3 μm emission from numerous low-redshift galaxies.
Abstract Copyright:
© 2025. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Luminous infrared galaxies - Ultraluminous infrared galaxies - Starburst galaxies - Polycyclic aromatic hydrocarbons - Molecular gas - Star formation - Galaxies
Simbad objects:
51
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