In:
The Astrophysical Journal, American Astronomical Society, Vol. 940, No. 2 ( 2022-12-01), p. 176-
Abstract:
We measure the molecular-to-atomic gas ratio, R mol , and the star formation rate (SFR) per unit molecular gas mass, SFE mol , in 38 nearby galaxies selected from the Virgo Environment Traced in CO (VERTICO) survey. We stack ALMA 12 CO ( J = 2−1) spectra coherently using H i velocities from the VIVA survey to detect faint CO emission out to galactocentric radii r gal ∼ 1.2 r 25 . We determine the scale lengths for the molecular and stellar components, finding a ∼3:5 relation compared to ∼1:1 in field galaxies, indicating that the CO emission is more centrally concentrated than the stars. We compute R mol as a function of different physical quantities. While the spatially resolved R mol on average decreases with increasing radius, we find that the mean molecular-to-atomic gas ratio within the stellar effective radius R e , R mol ( r 〈 R e ), shows a systematic increase with the level of H i , truncation and/or asymmetry (H I perturbation). Analysis of the molecular- and the atomic-to-stellar mass ratios within R e , R ⋆ mol ( r 〈 R e ) and R ⋆ atom ( r 〈 R e ) , shows that VERTICO galaxies have increasingly lower R ⋆ atom ( r 〈 R e ) for larger levels of H I perturbation (compared to field galaxies matched in stellar mass), but no significant change in R ⋆ m o l ( r 〈 R e ) . We also measure a clear systematic decrease of the SFE mol within R e , SFE mol ( r 〈 R e ), with increasingly perturbed H i . Therefore, compared to field galaxies from the field, VERTICO galaxies are more compact in CO emission in relation to their stellar distribution, but increasingly perturbed atomic gas increases their R mol and decreases the efficiency with which their molecular gas forms stars.
Type of Medium:
Online Resource
ISSN:
0004-637X
,
1538-4357
DOI:
10.3847/1538-4357/ac9d3c
Language:
Unknown
Publisher:
American Astronomical Society
Publication Date:
2022
detail.hit.zdb_id:
2207648-7
detail.hit.zdb_id:
1473835-1
SSG:
16,12
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