Physical Properties and Scaling Relations of Molecular Clouds: the Impact of Star Formation

Abstract

Using hydrodynamical simulations of a Milky Way-like galaxy, reaching 4.6 pc resolution, we study how the choice of star formation criteria impacts both galactic and Giant Molecular Clouds (GMC) scales. We find that using a turbulent, self-gravitating star formation criteria leads to an increase in the fraction of gas with densities between 10 and 10${}^4$ cm${}^{-3}$ when compared with a simulation using a molecular star formation method, despite both having nearly identical gaseous and stellar morphologies. Furthermore, we find that the site of star formation is effected with the the former tending to only produce stars in regions of very high density ($>10$ cm${}^{-3}$) gas while the latter forms stars along the entire length of its spiral arms. The properties of GMCs are impacted by the choice of star formation criteria with the former method producing larger clouds. Despite the differences we find that the relationships between clouds properties, such as the Larson relations, remain unaffected. Finally, the scatter in the measured star formation efficiency per free-fall time of GMCs remains present with both methods and is thus set by other factors.

18 Pages, 15 Figures, Accepted for publication in Monthly Notices of the Royal Astronomical Society

References in corpus (22)

• Theory of Star Formation
• Slow Star Formation in Dense Gas: Evidence and Implications
• The Atomic to Molecular Transition in Galaxies. II: HI and H_2 Column Densities
• Momentum Injection by Supernovae in the Interstellar Medium
• Physical properties of molecular clouds for the entire Milky Way disk
• Inefficient star formation through turbulence, magnetic fields and feedback
• The Atomic to Molecular Transition in Galaxies. I: An Analytic Approximation for Photodissociation Fronts in Finite Clouds
• On the interplay between star formation and feedback in galaxy formation simulations
• CO-dark gas and molecular filaments in Milky Way type galaxies
• Feedback-regulated star formation and escape of LyC photons from mini-haloes during reionisation
• Modelling the supernova-driven ISM in different environments
• Observational Evidence of Dynamic Star Formation Rate in Milky Way Giant Molecular Clouds
• Cloud Scale ISM Structure and Star Formation in M51
• Star Formation Relations in the Milky Way
• The integrated properties of the molecular clouds from the JCMT CO(3-2) High Resolution Survey
• The impact of stellar feedback on the density and velocity structure of the interstellar medium
• Star formation laws and thresholds from ISM structure and turbulence
• Characterizing gravitational instability in turbulent multi-component galactic discs
• On the Observed Diversity of Star Formation Efficiencies in Giant Molecular Clouds
• The roles of stellar feedback and galactic environment in star forming molecular clouds
• Gas flows in the circumgalactic medium around simulated high-redshift galaxies
• The Effects of Protostellar Jet Feedback on Turbulent Collapse

Cited by in corpus (4)

• Giant Molecular Cloud Catalogues for PHANGS-ALMA: Methods and Initial Results
• Necessary conditions for the formation of filaments and star clusters in the cold neutral medium
• Cloud-cloud collisions triggering star formation in galaxy simulations
• On the Viability of Determining Galaxy Properties from Observations I: Star Formation Rates and Kinematics