ALMA CO(3-2) Observations of Star-Forming Filaments in a Gas-Poor Dwarf Spheroidal Galaxy

Abstract

We report ALMA observations of ${}^{12}$CO(3-2) and ${}^{13}$CO(3-2) in the gas-poor dwarf galaxy NGC 5253. These 0.3"(5.5 pc) resolution images reveal small, dense molecular gas clouds that are located in kinematically distinct, extended filaments. Some of the filaments appear to be falling into the galaxy and may be fueling its current star formation. The most intense CO(3-2) emission comes from the central $\sim$100 pc region centered on the luminous radio-infrared HII region known as the supernebula. The CO(3-2) clumps within the starburst region are anti-correlated with H$\alpha$ on $\sim$5 pc scales, but are well-correlated with radio free-free emission. Cloud D1, which enshrouds the supernebula, has a high ${}^{12}$CO/${}^{13}$CO ratio, as does another cloud within the central 100 pc starburst region, possibly because the clouds are hot. CO(3-2) emission alone does not allow determination of cloud masses as molecular gas temperature and column density are degenerate at the observed brightness, unless combined with other lines such as ${}^{13}$CO.

7 pages, 5 figures, Accepted to ApJ

References in corpus (6)

• Bias-free Measurement of Giant Molecular Cloud Properties
• Effective destruction of CO by cosmic rays: implications for tracing H${}_2$ gas in the Universe
• Highly efficient star formation in NGC 5253 possibly from stream-fed accretion
• Inflows and Outflows in the Dwarf Starburst Galaxy NGC 5253: High-Resolution HI Observations
• Tests of star formation metrics in the low metallicity galaxy NGC 5253 using ALMA observations of H30$\alpha$ line emission
• ALMA Reveals Potential Localized Dust Enrichment from Massive Star Clusters in II Zw 40

Cited by in corpus (5)

• The Three Young Nuclear Super Star Clusters in NGC 5253
• Molecular Gas in the Nuclear Region of NGC 6240
• Molecular gas properties in young stellar clusters with a suppressed star cluster wind
• Ionized Gas in the NGC 5253 Supernebula:High Spatial and Spectral Resolution Observations with the JVLA and TEXES
• The heart of NGC 5253 as seen with MUSE-NFM: nitrogen enrichment through stellar chemical feedback at parsec scales