LMC+: Large-scale mapping of [CII] and [OIII] in the LMC molecular ridge, I. Dataset and line ratio analyses

Abstract

The fundamental process of star formation in galaxies involves the interplay between the fueling of star formation via molecular gas and the feedback from recently formed massive stars. This process, by which galaxies evolve, is also closely connected to the intrinsic properties of the interstellar medium (ISM). To study the role that different molecular and atomic phases of the ISM play in star formation, and to characterize their physical conditions, we zoom into our nearest neighboring galaxy, the Large Magellanic Cloud (LMC; 50 kpc). The LMC offers a view of the ISM and star formation conditions in a low metallicity environment similar to, in that regard, the epoch of the peak of star formation in the earlier universe. We present an unprecedentedly detailed analysis of a well-known star-forming regions (SFRs) at a spatial resolution of a few pc. We mapped a 610pcx260pc region in the LMC molecular ridge in [CII] and the [OIII] using the FIFI-LS instrument on the SOFIA telescope. We compare the data with the distribution of the CO (2-1) emission from ALMA, the modeled TIR luminosity as well as Spitzer/MIPS continuum and Halpha. We also provide a detailed description of the observing strategy and the data reduction. We find that [CII] and [OIII] emission is associated with the SFRs in the molecular ridge, but also extends throughout the mapped region, not obviously associated with ongoing star formation. The CO emission is clumpier than the [CII] emission and we find plentiful [CII] present where there is little CO emission, possibly holding important implications for CO-dark gas. We find a clear trend of the [CII]/TIR ratio decreasing with increasing TIR. This suggests a strong link between the [CII]-deficit and the local physical conditions instead of global properties.

15 pages, 9 figures, 3 tables, accepted to Astronomy & Astrophysics

References in corpus (31)

• CASA, the Common Astronomy Software Applications for Radio Astronomy
• The Herschel Dwarf Galaxy Survey: I. Properties of the low-metallicity ISM from PACS spectroscopy
• Reionization Era Bright Emission Line Survey: Selection and Characterization of Luminous Interstellar Medium Reservoirs in the z>6.5 Universe
• PHANGS-ALMA Data Processing and Pipeline
• Tracing the total molecular gas in galaxies: [CII] and the CO-dark gas
• Photodissociation and X-Ray Dominated Regions
• The ALPINE-ALMA [CII] survey. Little to no evolution in the [CII]-SFR relation over the last 13 Gyr
• New Constraints on the ${}^{12}$CO(2-1)/(1-0) Line Ratio Across Nearby Disc Galaxies
• A Problem with the Clustering of Recent Measures of the Distance to the Large Magellanic Cloud
• A Nearby Galaxy Perspective on Dust Evolution. Scaling relations and constraints on the dust build-up in galaxies with the DustPedia and DGS samples
• The Spatially Resolved [CII] Cooling Line Deficit in Galaxies
• The Herschel Dwarf Galaxy Survey: II. Physical conditions, origin of [CII] emission, and porosity of the multiphase low-metallicity ISM
• On the duration of the embedded phase of star formation
• The CO-dark molecular gas mass in 30 Doradus
• The 30 Doradus Molecular Cloud at 0.4 pc Resolution with the Atacama Large Millimeter/submillimeter Array: Physical Properties and the Boundedness of CO-emitting Structures
• Inferring the HII region escape fraction of ionizing photons from infrared emission lines in metal-poor star-forming dwarf galaxies
• Star Formation and Molecular Gas Diagnostics with Mid- and Far-Infrared Emission
• Calibrating mid-infrared emission as a tracer of obscured star formation on HII-region scales in the era of JWST
• The ALMA-CRISTAL survey: Gas, dust, and stars in star-forming galaxies when the Universe was ~1 Gyr old I. Survey overview and case studies
• SOFIA/FIFI-LS Full-disk [CII] Mapping and CO-dark Molecular Gas across the Nearby Spiral Galaxy NGC 6946
• Characterizing the Multi-Phase Origin of [CII] Emission in M101 and NGC 6946 with Velocity Resolved Spectroscopy
• [CII] $158\mu \mathrm{m}$ line emission from Orion A. I. A template for extragalactic studies?
• A joint deconvolution algorithm to combine single dish and interferometer data for wideband multi-term and mosaic imaging
• Probing the atmospheric precipitable water vapor with SOFIA, Part I, Measurements of the water vapor overburden with FIFI-LS
• First detection of [13CII] in the Large Magellanic Cloud
• CO(2-1)/CO(1-0) line ratio on $\sim$100 parsec scale in the nearby barred galaxy NGC1300
• [CII] map of the molecular ring and arms of the spiral galaxy NGC 7331
• Gas and dust cooling along the major axis of M33 (HerM33es) -- Herschel/PACS [CII] and [OI] observations
• A Molecular Gas Ring Hidden in the Sombrero Galaxy
• The Dark Energy Camera Magellanic Clouds Emission-Line Survey
• Disentangling emission from star-forming regions in the Magellanic Clouds: Linking [OIII]88 micron and 24 micron