Molecular Cloud Populations in the Context of Their Host Galaxy Environments: A Multiwavelength Perspective

Abstract

We present a rich, multiwavelength, multiscale database built around the PHANGS-ALMA CO(2-1) survey and ancillary data. We use this database to present the distributions of molecular cloud populations and sub-galactic environments in 80 PHANGS galaxies, to characterize the relationship between population-averaged cloud properties and host galaxy properties, and to assess key timescales relevant to molecular cloud evolution and star formation. We show that PHANGS probes a wide range of kpc-scale gas, stellar, and star formation rate (SFR) surface densities, as well as orbital velocities and shear. The population-averaged cloud properties in each aperture correlate strongly with both local environmental properties and host galaxy global properties. Leveraging a variable selection analysis, we find that the kpc-scale surface densities of molecular gas and SFR tend to possess the most predictive power for the population-averaged cloud properties. Once their variations are controlled for, galaxy global properties contain little additional information, which implies that the apparent galaxy-to-galaxy variations in cloud populations are likely mediated by kpc-scale environmental conditions. We further estimate a suite of important timescales from our multiwavelength measurements. The cloud-scale free-fall time and turbulence crossing time are $\sim 5-20$ Myr, comparable to previous cloud lifetime estimates. The timescales for orbital motion, shearing, and cloud-cloud collisions are longer, $\sim 100$ Myr. The molecular gas depletion time is $1-3$ Gyr and shows weak to no correlations with the other timescales in our data. We publish our measurements online and expect them to have broad utility to future studies of molecular clouds and star formation.

32 pages + 6 appendices. AJ in press. Data products available at https://www.canfar.net/storage/list/phangs/RELEASES/Sun_etal_2022 . Associated software package available at https://doi.org/10.5281/zenodo.6584842 . Slides summarizing the key results can be found at https://www.dropbox.com/s/7llnrob9wi0isfk/Sun_et_PHANGS_2022.pptx?dl=0

References in corpus (56)

• Array Programming with NumPy
• Theory of Star Formation
• HyperLEDA. III. The catalogue of extragalactic distances
• The Resolved Properties of Extragalactic Giant Molecular Clouds
• GALEX-SDSS-WISE Legacy Catalog (GSWLC): Star Formation Rates, Stellar Masses and Dust Attenuations of 700,000 Low-redshift Galaxies
• Physical properties of molecular clouds for the entire Milky Way disk
• Bias-free Measurement of Giant Molecular Cloud Properties
• A z=0 Multi-wavelength Galaxy Synthesis I: A WISE and GALEX Atlas of Local Galaxies
• The lifecycle of molecular clouds in nearby star-forming disc galaxies
• Fast and inefficient star formation due to short-lived molecular clouds and rapid feedback
• ALMA Reveals the Molecular Medium Fueling the Nearest Nuclear Starburst
• Distances to PHANGS Galaxies: New Tip of the Red Giant Branch Measurements and Adopted Distances
• The Abundance Properties of Nearby Late-Type Galaxies.I. The Data
• Dynamically Driven Evolution of the Interstellar Medium in M51
• PHANGS CO kinematics: disk orientations and rotation curves at 150 pc resolution
• Giant Molecular Cloud Catalogues for PHANGS-ALMA: Methods and Initial Results
• Observational Evidence of Dynamic Star Formation Rate in Milky Way Giant Molecular Clouds
• Cloud Scale ISM Structure and Star Formation in M51
• The Perils of Clumpfind: The Mass Spectrum of Sub-structures in Molecular Clouds
• New Constraints on the ${}^{12}$CO(2-1)/(1-0) Line Ratio Across Nearby Disc Galaxies
• Six Myths on the Virial Theorem for Interstellar Clouds
• Molecular Gas in the Low Metallicity, Star Forming Dwarf IC 10
• The frequency and nature of `cloud-cloud collisions' in galaxies
• The molecular cloud lifecycle
• A Portrait of Cold Gas in Galaxies at 60pc Resolution and a Simple Method to Test Hypotheses That Link Small-Scale ISM Structure to Galaxy-Scale Processes
• SIGAME simulations of the [CII], [OI] and [OIII] line emission from star forming galaxies at z ~ 6
• Star Formation Relations in the Milky Way
• The SAMI Galaxy Survey: Exploring the gas-phase Mass-Metallicity Relation
• On the duration of the embedded phase of star formation
• Physical Properties of Molecular Clouds at 2 parsec Resolution in the Low-Metallicity Dwarf Galaxy NGC 6822 and the Milky Way
• The dynamical evolution of molecular clouds near the Galactic Centre - II. Spatial structure and kinematics of simulated clouds
• Physical Processes in Star Formation
• CO line emission from galaxies in the Epoch of Reionization
• The ALMaQUEST Survey: V. The non-universality of kpc-scale star formation relations and the factors that drive them
• The integrated properties of the molecular clouds from the JCMT CO(3-2) High Resolution Survey
• Giant Molecular Clouds in the Early-Type Galaxy NGC4526
• The Interstellar Medium and Star Formation in Edge-On Galaxies. II. NGC 4157, 4565, and 5907
• From diffuse gas to dense molecular cloud cores
• Ubiquitous velocity fluctuations throughout the molecular interstellar medium
• CO Multi-line Imaging of Nearby Galaxies (COMING) IV. Overview of the Project
• The EDGE-CALIFA survey: The local and global relations between ${\Sigma }_{\ast }$ , ${\Sigma }_{SFR}$ and ${\Sigma }_{mol}$ that regulate star-formation
• Comparing the pre-SNe feedback and environmental pressures for 6000 HII regions across 19 nearby spiral galaxies
• The role of galactic dynamics in shaping the physical properties of giant molecular clouds in Milky Way-like galaxies
• Molecular Gas Properties and CO-to-H2 Conversion Factors in the Central Kiloparsec of NGC 3351
• WISDOM Project -- X. The morphology of the molecular ISM in galaxy centres and its dependence on galaxy structure
• WISDOM Project -- IX Giant Molecular Clouds in the Lenticular Galaxy NGC4429: Effects of Shear and Tidal Forces on Clouds
• Energy budget of forming clumps in numerical simulations of collapsing clouds
• The headlight cloud in NGC 628: An extreme giant molecular cloud in a typical galaxy disk
• Frequency and nature of central molecular outflows in nearby star-forming disk galaxies
• The Gas-Star Formation Cycle in Nearby Star-forming Galaxies II. Resolved Distributions of CO and H$\alpha$ Emission for 49 PHANGS Galaxies
• Bird's eye view of molecular clouds in the Milky Way: I. Column density and star formation from sub-pc to kpc scales
• CO Multi-line Imaging of Nearby Galaxies (COMING): VI. Radial variations in star formation efficiency
• NOEMA High Fidelity Imaging of the Molecular Gas in and around M82
• Comparing the Properties of GMCs in M33 from Simulations and Observations
• Highly turbulent gas on GMC-scales in NGC 3256, the nearest luminous infrared galaxy
• Spatial Power Spectra of Dust across the Local Group: No Constraint on Disc Scale Height

Cited by in corpus (51)

• The PHANGS-JWST Treasury Survey: Star Formation, Feedback, and Dust Physics at High Angular resolution in Nearby GalaxieS
• Star Formation Laws and Efficiencies across 80 Nearby Galaxies
• Environmental dependence of the molecular cloud lifecycle in 54 main sequence galaxies
• Introducing TIGRESS-NCR: I. Co-Regulation of the Multiphase Interstellar Medium and Star Formation Rates
• PHANGS-JWST First Results: Mid-infrared emission traces both gas column density and heating at 100 pc scales
• The Physical Drivers and Observational Tracers of CO-to-H2 Conversion Factor Variations in Nearby Barred Galaxy Centers
• Stellar feedback in M83 as observed with MUSE -- II. Analysis of the HII region population: ionisation budget and pre-SN feedback
• PHANGS-JWST First Results: Rapid Evolution of Star Formation in the Central Molecular Gas Ring of NGC1365
• Massive star cluster formation I. High star formation efficiency while resolving feedback of individual stars
• PHANGS-JWST First Results: The Dust Filament Network of NGC 628 and its Relation to Star Formation Activity
• PHANGS--JWST First Results: ISM structure on the turbulent Jeans scale in four disk galaxies observed by JWST and ALMA
• Chemical Evolution with Radial Mixing Redux: Extending beyond the Solar Neighborhood
• Fuelling the nuclear ring of NGC 1097
• VERTICO III: The Kennicutt-Schmidt relation in Virgo cluster galaxies
• A 3D View of Orion: I. Barnard's Loop
• PHANGS-MeerKAT and MHONGOOSE HI observations of nearby spiral galaxies: physical drivers of the molecular gas fraction, $R_{\mathrm{mol}}$
• The PHANGS-HST-Halpha Survey: Warm Ionized Gas Physics at High Angular resolution in Nearby GalaxieS with the Hubble Space Telescope
• Molecular gas and star formation in nearby starburst galaxy mergers
• Simulating nearby disc galaxies on the main star formation sequence I. Bar formation and the building of the central gas reservoir
• Wide-field CO isotopologue emission and the CO-to-H${}_2$ factor across the nearby spiral galaxy M101
• Linking stellar populations to HII regions across nearby galaxies. II. Infrared Reprocessed and UV Direct Radiation Pressure in HII Regions
• Large-scale turbulent driving regulates star formation in high-redshift gas-rich galaxies II: Influence of the magnetic field and the turbulent compressive fraction
• The Karl G. Jansky Very Large Array Local Group L-band Survey (LGLBS)
• Comparing the Locations of Supernovae to CO (2-1) Emission in their Host Galaxies
• Necessary conditions for the formation of filaments and star clusters in the cold neutral medium
• Kpc-scale properties of dust temperature in terms of dust mass and star formation activity
• Sub-kiloparsec empirical relations and excitation conditions of HCN and HCO+ J=3-2 in nearby star-forming galaxies
• 3D structure of the Milky Way out to 10 kpc from the Sun. Catalogue of large molecular clouds in the Galactic Plane
• The impact of HII regions on Giant Molecular Cloud properties in nearby galaxies sampled by PHANGS ALMA and MUSE
• Dense gas scaling relations at kiloparsec scales across nearby galaxies with the ALMA ALMOND and IRAM 30m EMPIRE surveys
• Reconciling extragalactic star formation efficiencies with theory: insights from PHANGS
• A sensitive, high-resolution, wide-field IRAM NOEMA CO(1-0) survey of the very nearby spiral galaxy IC 342
• CO-CAVITY project: Molecular gas and star formation in void galaxies
• The life cycle of giant molecular clouds in simulated Milky Way-mass galaxies
• Giant molecular clouds and their Type classification in M74: Toward understanding star formation and cloud evolution
• Filamentary Hierarchies and Superbubbles I: Characterizing filament properties across a simulated spiral galaxy
• Duration and properties of the embedded phase of star formation in 37 nearby galaxies from PHANGS-JWST
• Modeling the Mass Distribution and Gravitational Potential of Nearby Disk Galaxies: Implications for the ISM Dynamical Equilibrium
• A 260 pc resolution ALMA map of HCN(1-0) in the galaxy NGC 4321
• Star formation drivers across the M33 disk
• Simulating nearby disc galaxies on the main star formation sequence II. The gas structure transition in low and high stellar mass discs
• The Hierarchical Dynamical State of Molecular Gas from 3 to 300 pc in NGC 253
• The Arp 240 Galaxy Merger: A Detailed Look at the Molecular Kennicutt-Schmidt Star Formation Law on Sub-kpc Scales
• The $H_2$ angular momentum -- mass relation of local disc galaxies
• Gravitational instability and spatial regularity of the gas clouds and young stellar population in spiral arms of NGC 628
• Cloud populations versus galactic environment in NGC4689, NGC628, NGC1566, and NGC4321
• Kennicutt-Schmidt relation of galaxies over 13 billion years in the COLIBRE hydrodynamical simulations
• Molecular gas and star formation in central rings across nearby galaxies
• Massive Star Clusters in the Semi-Analytical Galaxy Formation Model L-Galaxies 2020
• Galaxy Activity, Torus and Outflow Survey (GATOS) X: Molecular gas clumpiness under the influence of AGN
• Spatially Resolved Star Formation relations in local LIRGs along the complete merger sequence