From Gas to Stars in Energetic Environments: Dense Gas Clumps in the 30 Doradus Region Within the Large Magellanic Cloud

Abstract

We present parsec scale interferometric maps of HCN(1-0) and HCO${}^{+}$(1-0) emission from dense gas in the star-forming region 30 Doradus, obtained using the Australia Telescope Compact Array. This extreme star-forming region, located in the Large Magellanic Cloud (LMC), is characterized by a very intense ultraviolet ionizing radiation field and sub-solar metallicity, both of which are expected to impact molecular cloud structure. We detect 13 bright, dense clumps within the 30 Doradus-10 giant molecular cloud. Some of the clumps are aligned along a filamentary structure with a characteristic spacing that is consistent with formation via the varicose fluid instability. Our analysis shows that the filament is gravitationally unstable and collapsing to form stars. There is a good correlation between HCO${}^{+}$ emission in the filament and signatures of recent star formation activity including H${}_2$O masers and young stellar objects (YSOs). YSOs seem to continue along the same direction of the filament toward the massive compact star cluster R136 in the southwest. We present detailed comparisons of clump properities (masses, linewidths, sizes) in 30Dor-10 to those in other star forming regions of the LMC (N159, N113, N105, N44). Our analysis shows that the 30Dor-10 clumps have similar mass but wider linewidths and similar HCN/HCO${}^{+}$ (1-0) line ratios as clumps detected in other LMC star-forming regions. Our results suggest that the dense molecular gas clumps in the interior of 30Dor-10 are well-shielded against the intense ionizing field that is present in the 30Doradus region.

Accepted in The Astrophysical Journal

References in corpus (8)

• Theory of Star Formation
• Diagnostics of irradiated dense gas in galaxy nuclei. II. A grid of XDR and PDR models
• Bias-free Measurement of Giant Molecular Cloud Properties
• A multi-transition HCN and HCO+ study of 12 nearby active galaxies: AGN versus SB environments
• The VLT-FLAMES survey of massive stars: constraints on stellar evolution from the chemical compositions of rapidly rotating Galactic and Magellanic Cloud B-type stars
• Dense gas in luminous infrared galaxies
• Is HCN a True Tracer of Dense Molecular Gas in LIRGs and ULIRGs?
• Abundances and Isotope Ratios in the Magellanic Clouds: The Star Forming Environment of N113

Cited by in corpus (12)

• The headlight cloud in NGC 628: An extreme giant molecular cloud in a typical galaxy disk
• Dense molecular gas properties on 100 pc scales across the disc of NGC 3627
• Dense gas in low-metallicity galaxies
• Chemistry and physics of a low-metallicity hot core in the Large Magellanic Cloud
• Pillars of creation amongst destruction: Star formation in molecular clouds near R136 in 30 Doradus
• DeGaS-MC: Dense Gas Survey in the Magellanic Clouds I -- An APEX survey of HCO+ and HCN(2-1) toward the LMC and SMC
• Molecular and Ionized Hydrogen in 30 Doradus. I. Imaging Observations
• ALMA Observations of the Physical and Chemical Conditions in Centaurus A
• The Evolution of NGC 7465 as Revealed by its Molecular Gas Properties
• Dense gas and star formation in the Outer Milky Way
• ALMA Observations of HCO+ and HCN Emission in a massive star forming region N55 of the Large Magellanic Cloud
• PRUSSIC II -- ALMA imaging of dense-gas tracers in SDP.81: Evidence for low mechanical heating and a sub-solar metallicity in a z=3.04 dusty galaxy