Fragmentation in Molecular Clouds and its connection to the IMF

Abstract

We present an analysis of star-forming gas cores in an SPH simulation of a Giant Molecular Cloud. We identify cores using their deep potential wells. This yields a smoother distribution with clearer boundaries than density. Additionally, this gives an indication of future collapse, as bound potential cores (p-cores) represent the earliest stages of fragmentation in molecular clouds. We find that the mass function of the p-cores resembles the stellar IMF and the observed clump mass function, although p-core masses (~0.7 Msol) are smaller than typical density clumps. The bound p-cores are generally subsonic, have internal substructure, and are only quasi-spherical. We see no evidence of massive bound cores supported by turbulence. We trace the evolution of the p-cores forward in time, and investigate the connection between the original p-core mass and the stellar mass that formed from it. We find that there is a poor correlation, with considerable scatter suggesting accretion onto the core is dependent on more factors than just the initial core mass. During the accretion process the p-cores accrete from beyond the region first bound, highlighting the importance of the core environment to its subsequent evolution.

12 pages, 12 figures and 3 tables. Accepted by MNRAS

References in corpus (21)

• Cold Dark Clouds: The Initial Conditions for Star Formation
• Analytical theory for the initial mass function: CO clumps and prestellar cores
• Structural Analysis of Molecular Clouds: Dendrograms
• Radiation-Hydrodynamic Simulations of Collapse and Fragmentation in Massive Protostellar Cores
• Star formation through gravitational collapse and competitive accretion
• The Mass Distribution and Lifetime of Prestellar Cores in Perseus, Serpens, and Ophiuchus
• CO Isotopologues in the Perseus Molecular Cloud Complex: the X-Factor and Regional Variations
• The Importance of Radiative Feedback for the Stellar Initial Mass Function
• The Nature of the Dense Core Population in the Pipe Nebula: Thermal Cores Under Pressure
• A SCUBA survey of Orion, the low-mass end of the core mass function
• The effect of magnetic fields on star cluster formation
• On the Constancy of the Characteristic Mass of Young Stars
• Clump Lifetimes and the Initial Mass Function
• The relationship between the prestellar core mass function and the stellar initial mass function
• The structure of molecular clouds and the universality of the clump mass function
• The initial conditions of star formation VIII: an observational study of the Ophiuchus cloud L1688 and implications for the prestellar core mass function
• Dust Emission from the Perseus Molecular Cloud
• On the Evolution of the Dense Core Mass Function
• Protostar Mass Due to Infall and Dispersal
• Can We Trust the Dust? Evidence of Dust Segregation in Molecular Clouds
• On the fidelity of the core mass functions derived from dust column density data

Cited by in corpus (61)

• Comparing the statistics of interstellar turbulence in simulations and observations: Solenoidal versus compressive turbulence forcing
• Smoothed Particle Hydrodynamics in Astrophysics
• Turbulent molecular clouds
• The Big Problems in Star Formation: the Star Formation Rate, Stellar Clustering, and the Initial Mass Function
• The Formation and Early Evolution of Low-mass Stars and Brown Dwarfs
• Radiation-Hydrodynamic Simulations of the Formation of Orion-Like Star Clusters II. The Initial Mass Function from Winds, Turbulence, and Radiation
• The Simultaneous Formation of Massive Stars and Stellar Clusters
• The dynamical state of stellar structure in star-forming regions
• The dynamics and outcome of star formation with jets, radiation, winds, and supernovae in concert
• Characterizing the Cool KOIs IV: Kepler-32 as a prototype for the formation of compact planetary systems throughout the Galaxy
• The Protostellar Luminosity Function
• Dense core formation in supersonic turbulent converging flows
• The Age, Stellar Content and Star Formation Timescale of the B59 Dense Core
• Gravitational Collapse and Filament Formation: Comparison with the Pipe Nebula
• Line Profiles of Cores within Clusters: I. The Anatomy of a Filament
• The SILCC project - V. The impact of magnetic fields on the chemistry and the formation of molecular clouds
• Simulating Star Clusters Across Cosmic Time: I. Initial Mass Function, Star Formation Rates and Efficiencies
• Formation of proto-cluster: a virialized structure from gravo-turbulent collapse I. Simulation of cluster formation in collapsing molecular cloud
• The Initial Mass Function and Young Brown Dwarf Candidates in NGC 2264. IV. The Initial Mass Function and Star Formation History
• From the CMF to the IMF: Beyond the Core-Collapse Model
• Hierarchical fragmentation and collapse signatures in a high-mass starless region
• The Origin of the Stellar Mass Distribution and Multiplicity
• Prestellar Core Formation, Evolution, and Accretion from Gravitational Fragmentation in Turbulent Converging Flows
• Fragmentation and dynamical collapse of the starless high-mass star-forming region IRDC18310-4
• ALMA-IMF VI -- Investigating the origin of stellar masses: Core mass function evolution in the W43-MM2&MM3 mini-starburst
• Star Formation in Nuclear Rings of Barred Galaxies
• A quantification of the non-spherical geometry and accretion of collapsing cores
• Disc formation and fragmentation using radiative non-ideal magnetohydrodynamics
• Star formation: statistical measure of the correlation between the prestellar core mass function and the stellar initial mass function
• The core and stellar mass functions in massive collapsing filaments
• The Formation and Evolution of Small Star Clusters
• Flow-Driven Cloud Formation and Fragmentation: Results From Eulerian and Lagrangian Simulations
• The relation between accretion rates and the initial mass function in hydrodynamical simulations of star formation
• On the fragmentation boundary in magnetised self-gravitating discs
• Strong dependence of the physical properties of cores on spatial resolution in observations and simulations
• Does turbulence determine the initial mass function?
• The role of the turbulence driving mode for the Initial Mass Function
• A hybrid SPH/N-body method for star cluster simulations
• Fragmentation in the Massive Star-Forming Region IRAS 19410+2336
• Runaway massive stars as variable gamma-ray sources
• The highly variable time evolution of star-forming cores identified with dendrograms
• Fragmentation and kinematics in high-mass star formation: CORE-extension targeting two very young high-mass star-forming regions
• The Thermodynamics of Molecular Cloud Fragmentation: Star Formation Under Non-Milky Way Conditions
• On the emergent System Mass Function: the contest between accretion and fragmentation
• Implementation of stellar heating feedback in simulations of star cluster formation: effects on the initial mass function
• HST/NICMOS observations of the GLIMPSE9 stellar cluster
• Similarity between the C18O (J=1-0) core mass function and the IMF in the S 140 region
• G-virial: Gravity-based structure analysis of molecular clouds
• Statistical analysis of the mass-to-flux ratio in turbulent cores: effects of magnetic field reversals and dynamo amplification
• ALMA-IMF XVI: Mass-averaged temperature of cores and protostellar luminosities in the ALMA-IMF protoclusters
• The fragmentation of expanding shells III: Oligarchic accretion and the mass spectrum of fragments
• Unbound Star-forming Molecular Clouds
• The structure and kinematics of dense gas in NGC 2068
• On the Coagulation and Size Distribution of Pressure Confined Cores
• A rotating helical filament in the L1251 dark cloud
• On the IMF in a Triggered Star Formation Context
• Tensor classification of structure in smoothed particle hydrodynamics density fields
• Clustered Star Formation: A Review
• Theory of Feedback in Clusters and Molecular Cloud Turbulence
• The interdependence between density PDF, CMF and IMF and their relation with Mach number in simulations
• A Fast and Simple Algorithm for Detecting Large Scale Structures