Simulations of the star-forming molecular gas in an interacting M51-like galaxy: cloud population statistics

Abstract

To investigate how molecular clouds react to different environmental conditions at a galactic scale, we present a catalogue of giant molecular clouds resolved down to masses of $\sim 10$~M${}_{\odot }$ from a simulation of the entire disc of an interacting M51-like galaxy and a comparable isolated galaxy. Our model includes time-dependent gas chemistry, sink particles for star formation and supernova feedback, meaning we are not reliant on star formation recipes based on threshold densities and can follow the physics of the cold molecular phase. We extract giant molecular clouds at a given timestep of the simulations and analyse their properties. In the disc of our simulated galaxies, spiral arms seem to act merely as snowplows, gathering gas and clouds without dramatically affecting their properties. In the centre of the galaxy, on the other hand, environmental conditions lead to larger, more massive clouds. While the galaxy interaction has little effect on cloud masses and sizes, it does promote the formation of counter-rotating clouds. We find that the identified clouds seem to be largely gravitationally unbound at first glance, but a closer analysis of the hierarchical structure of the molecular interstellar medium shows that there is a large range of virial parameters with a smooth transition from unbound to mostly bound for the densest structures. The common observation that clouds appear to be virialised entities may therefore be due to CO bright emission highlighting a specific level in this hierarchical binding sequence. The small fraction of gravitationally bound structures found suggests that low galactic star formation efficiencies may be set by the process of cloud formation and initial collapse.

arXiv comment22 pages, 26 figures, 2 tables. Properties of the clouds in the catalog are provided as a supplementary file

References in corpus (71)

• On the variation of the Initial Mass Function
• E pur si muove: Galiliean-invariant cosmological hydrodynamical simulations on a moving mesh
• A General Theory of Turbulence-Regulated Star Formation, From Spirals to ULIRGs
• The Star Formation Rate of Turbulent Magnetized Clouds: Comparing Theory, Simulations, and Observations
• Re-examining Larson's Scaling Relationships in Galactic Molecular Clouds
• Structural Analysis of Molecular Clouds: Dendrograms
• Magnetic Fields in Spiral Galaxies
• The Star Formation Rate of Supersonic MHD Turbulence
• A Super-Alfvenic Model of Dark Clouds
• Bias-free Measurement of Giant Molecular Cloud Properties
• Turbulent Flow-Driven Molecular Cloud Formation: A Solution to the Post-T Tauri Problem?
• Low Virial Parameters in Molecular Clouds: Implications for High Mass Star Formation and Magnetic Fields
• Star Formation in Disk Galaxies. I. Formation and Evolution of Giant Molecular Clouds via Gravitational Instability and Cloud Collisions
• Analytical star formation rate from gravoturbulent fragmentation
• The PdBI Arcsecond Whirlpool Survey (PAWS): Environmental Dependence of Giant Molecular Cloud Properties in M51
• Inefficient star formation through turbulence, magnetic fields and feedback
• Gravity or Turbulence? The velocity dispersion-size relation
• ALMA Reveals the Molecular Medium Fueling the Nearest Nuclear Starburst
• Giant Molecular Clouds in M33 -- II. High Resolution Observations
• CO-dark gas and molecular filaments in Milky Way type galaxies
• Feedback from Winds and Supernovae in Massive Stellar Clusters. I: Hydrodynamics
• A Comparative Study of Giant Molecular Clouds in M51, M33 and the Large Magellanic Cloud
• Physical vs. Observational Properties of Clouds in Turbulent Molecular Cloud Models
• Why are most molecular clouds not gravitationally bound?
• Modelling the supernova-driven ISM in different environments
• TreeCol: a novel approach to estimating column densities in astrophysical simulations
• Molecular Gas Properties on Cloud Scales Across the Local Star-forming Galaxy Population
• The linewidth-size relationship in the dense ISM of the Central Molecular Zone
• SEDIGISM: Structure, excitation, and dynamics of the inner Galactic interstellar medium
• The Star Formation Rate in the Gravoturbulent Interstellar Medium
• Physical Properties of Giant Molecular Clouds in the Large Magellanic Cloud
• Larson's third law and the universality of molecular cloud structure
• A Detailed Study of Feedback from a Massive Star
• Quantifying Observational Projection Effects Using Molecular Cloud Simulations
• Simulations of the Milky Way's central molecular zone -- I. Gas dynamics
• Graph-based interpretation of the Molecular Interstellar Medium Segmentation
• Tracing the formation of molecular clouds via [CII], [CI] and CO emission
• Simulations of the star-forming molecular gas in an interacting M51-like galaxy
• A supersonic turbulence origin of Larson's laws
• Simulations of the Milky Way's central molecular zone -- II. Star formation
• Gravitational contraction versus Supernova driving and the origin of the velocity dispersion-size relation in molecular clouds
• Approximations for modelling CO chemistry in GMCs: a comparison of approaches
• The Life Cycle of the Central Molecular Zone. I: Inflow, Star Formation, and Winds
• Does External Pressure Explain Recent Results for Molecular Clouds?
• A general theory for the lifetimes of giant molecular clouds under the influence of galactic dynamics
• The ALMA view of GMCs in NGC 300: Physical Properties and Scaling Relations at 10 pc Resolution
• What can simulated molecular clouds tell us about real molecular clouds?
• The SEDIGISM survey: Molecular clouds in the inner Galaxy
• On the structure of molecular clouds
• Local Simulations of Spiral Galaxies with the TIGRESS Framework: I. Star Formation and Arm Spurs/Feathers
• A simple method to convert sink particles into stars
• CHIMPS: Physical properties of molecular clumps across the inner Galaxy
• Angular Momentum in Giant Molecular Clouds. I. The Milky Way
• The Interstellar Medium and star formation on kpc size scales
• The role of galactic dynamics in shaping the physical properties of giant molecular clouds in Milky Way-like galaxies
• Gravity or turbulence? IV. Collapsing cores in out-of-virial disguise
• Properties and rotation of molecular clouds in M 33
• The evolution of Giant Molecular Filaments
• The history of dynamics and stellar feedback revealed by the HI filamentary structure in the disk of the Milky Way
• Strong excess Faraday rotation on the Inside of the Sagittarius spiral arm
• Angular Momentum in Giant Molecular Clouds. II. M33
• On the resolution requirements for modelling molecular gas formation in solar neighbourhood conditions
• Rotation of molecular clouds in M~51
• How do different spiral arm models impact the ISM and GMC population?
• Comparing the Properties of GMCs in M33 from Simulations and Observations
• The Interstellar Medium and Star Formation of Galactic Disks. I. ISM and GMC properties with Diffuse FUV and Cosmic Ray Backgrounds
• The changing GMC population in galaxy interactions
• Synthetic observations of spiral arm tracers of a simulated Milky Way analog
• The complete census of molecular hydrogen in a simulated disc galaxy
• Statistical analysis of the mass-to-flux ratio in turbulent cores: effects of magnetic field reversals and dynamo amplification
• ALMA Observations of the Molecular Clouds in NGC 625

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• Giant Molecular Cloud Catalogues for PHANGS-ALMA: Methods and Initial Results
• Molecular Cloud Populations in the Context of Their Host Galaxy Environments: A Multiwavelength Perspective
• Environmental dependence of the molecular cloud lifecycle in 54 main sequence galaxies
• PHANGS-JWST First Results: Multi-wavelength view of feedback-driven bubbles (The Phantom Voids) across NGC 628
• PHANGS-JWST First Results: Tracing the Diffuse ISM with JWST Imaging of Polycyclic Aromatic Hydrocarbon Emission in Nearby Galaxies
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• PHANGS-JWST First Results: The Dust Filament Network of NGC 628 and its Relation to Star Formation Activity
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• Diverse Molecular Structures Across The Whole Star-Forming Disk of M83: High fidelity Imaging at 40pc Resolution
• PHANGS-JWST First Results: Spurring on Star Formation: JWST Reveals Localised Star Formation in a Spiral Arm Spur of NGC 628
• PHANGS-ALMA: Arcsecond CO(2-1) Imaging of Nearby Star-Forming Galaxies
• On the distribution of the Cold Neutral Medium in galaxy discs
• Cloud properties across spatial scales in simulations of the interstellar medium
• Molecular clouds in M51 from high-resolution extinction mapping
• The Hierarchical Dynamical State of Molecular Gas from 3 to 300 pc in NGC 253
• The fragmentation of molecular clouds in starburst environments
• Insights into the structure and kinematics of a Milky Way-like galaxy
• Why most molecular clouds are gravitationally dominated
• PHANGS-MUSE: the HII region luminosity function of local star-forming galaxies