Surveying the Whirlpool at Arcseconds with NOEMA (SWAN): III. ${}^{13}$CO/C${}^{18}$O ratio variations across the M51 galaxy

Abstract

CO isotopologues are common tracers of the bulk molecular gas in extragalactic studies, providing insights into the physical and chemical conditions of the cold molecular gas, a reservoir for star formation. Since star formation occurs within molecular clouds, mapping CO isotopologues at cloud-scale is important to understanding the processes driving star formation. However, achieving this mapping at such scales is challenging and time-intensive. The Surveying the Whirlpool Galaxy at Arcseconds with NOEMA (SWAN) survey addresses this by using the Institut de radioastronomie millimétrique (IRAM) NOrthern Extended Millimeter Array (NOEMA) to map the ${}^{13}$CO(1-0) and C${}^{18}$O(1-0) isotopologues, alongside several dense gas tracers, in the nearby star-forming galaxy M51 at high sensitivity and spatial resolution ($\approx$ 125 pc).We examine the ${}^{13}$CO(1-0) to C${}^{18}$O(1-0) line emission ratio as a function of galactocentric radius and star formation rate surface density to infer how different chemical and physical processes affect this ratio at cloud scales across different galactic environments: nuclear bar, molecular ring, northern and southern spiral arms. In line with previous studies conducted at kiloparsec scales for nearby star-forming galaxies, we find a moderate positive correlation with galactocentric radius and a moderate negative correlation with star formation rate surface density across the field-of-view (FoV), with slight variations depending on the galactic environment. We propose that selective nucleosynthesis and changes in the opacity of the gas are the primary drivers of the observed variations in the ratio.

arXiv commentAccepted for publication in A&A; 8 pages, 4 pages Appendix, 10 figures

References in corpus (48)

• Star Formation in the Milky Way and Nearby Galaxies
• A Search for "Dwarf" Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies
• Molecular Gas and Star Formation in Nearby Disk Galaxies
• The Critical Density and the Effective Excitation Density of Commonly Observed Molecular Dense Gas Tracers
• The PdBI Arcsecond Whirlpool Survey (PAWS): Environmental Dependence of Giant Molecular Cloud Properties in M51
• The PdBI Arcsecond Whirlpool Survey (PAWS). I. A Cloud-Scale/Multi-Wavelength View of the Interstellar Medium in a Grand-Design Spiral Galaxy
• Gas Kinematics on GMC scales in M51 with PAWS: cloud stabilization through dynamical pressure
• The Plateau de Bure + 30m Arcsecond Whirlpool Survey reveals a thick disk of diffuse molecular gas in the M51 galaxy
• The evolution of CNO isotopes: a new window on cosmic star-formation history and the stellar IMF in the age of ALMA
• Molecules as tracers of galaxy evolution: an EMIR survey. I. Presentation of the data and first results
• A Mapping Survey of the 12CO and 13CO Emission in Galaxies
• Resolved Giant Molecular Clouds in Nearby Spiral Galaxies: Insights from the CANON CO (1-0) Survey
• The PdBI Arcsecond Whirlpool Survey (PAWS): Multi-phase cold gas kinematic of M51
• The local radio-IR correlation in M51
• Galactic interstellar 18O/17O ratios - a radial gradient?
• The Atlas3D Project -- XI. Dense molecular gas properties of CO-luminous early-type galaxies
• Full-disc ${}^{13}$CO(1-0) mapping across nearby galaxies of the EMPIRE survey and the CO-to-H${}_2$ conversion factor
• A lambda=3 mm molecular line survey of NGC1068. Chemical signatures of an AGN environment
• CI and CO in nearby galaxy centers: the bright galaxies NGC1068 (M77), NGC2146, NGC3079, NGC4826 (M64), and NGC7469
• The Density and Temperature of Molecular Clouds in M33
• The ${}^{12}$CO/${}^{13}$CO ratio in turbulent molecular clouds
• Dynamically Influenced Molecular Clouds in the Nucleus of NGC 6946: Variations in the CO Isotopic Line Ratios
• A New Diagnostic to Separate Line Emission from Star Formation, Shocks, and AGN Simultaneously in IFU Data
• Using CO line ratios to trace the physical properties of molecular clouds
• CI and CO in nearby galaxy centers. The star-burst galaxies NGC 278, NGC 660, NGC 3628, NGC 4631, and NGC 4666
• AGN feedback in the nucleus of M51
• The Physical Drivers and Observational Tracers of CO-to-H2 Conversion Factor Variations in Nearby Barred Galaxy Centers
• ${}^{13}$CO/C${}^{18}$O Gradients Across the Disks of Nearby Spiral Galaxies
• WISDOM Project -- X. The morphology of the molecular ISM in galaxy centres and its dependence on galaxy structure
• Detection of the ^3P_2 - ^3P_1 Submillimeter Transition of 13CI in the Interstellar Medium: Implication for Chemical Fractionation
• Gravitational torques imply molecular gas inflow towards the nucleus of M51
• Extreme CO Isotopic Abundances in the ULIRG IRAS 13120-5453: An Extremely Young Starburst or Top-Heavy Initial Mass Function
• Molecular Gas in SAURON Early-Type Galaxies: Detection of 13CO and HCN Emission
• Systematic variation of the 12CO/13CO ratio as a function of star-formation rate surface density
• Are local ULIRGs powered by AGN? The sub-kpc view of the 220 GHz continuum. PUMA II
• The Structure, Kinematics and Physical Properties of the Molecular Gas in the Starburst Nucleus of NGC 253
• The AMANOGAWA-2SB Galactic Plane Survey I: Data on the Galactic Equator
• Kinetic temperature of massive star forming molecular clumps measured with formaldehyde
• Extreme CO Isotopologue Line Ratios in ULIRGS: Evidence for a top-heavy IMF
• The ALMOND Survey: Molecular cloud properties and gas density tracers across 25 nearby spiral galaxies with ALMA
• A CO isotopologue Line Atlas within the Whirlpool galaxy Survey (CLAWS)
• Diverse Molecular Structures Across The Whole Star-Forming Disk of M83: High fidelity Imaging at 40pc Resolution
• ISM chemistry in metal rich environments: molecular tracers of metallicity
• CO Excitation and its Connection to Star Formation at 200 pc in NGC 1365
• Molecular Gas Kinematics and Line Diagnostics in Early-type Galaxies: NGC4710 and NGC5866
• Spectral Stacking of Radio-Interferometric Data
• Surveying the Whirlpool at Arcseconds with NOEMA (SWAN)- I. Mapping the HCN and N${}_2$H${}^{+}$ 3mm lines
• Surveying the Whirlpool at Arcseconds with NOEMA (SWAN) II: Survey design and observations