Investigating the structure of star-forming regions using INDICATE

Abstract

The ability to make meaningful comparisons between theoretical and observational data of star-forming regions is key to understanding the star formation process. In this paper we test the performance of INDICATE, a new method to quantify the clustering tendencies of individual stars in a region, on synthetic star-forming regions with sub-structured, and smooth, centrally concentrated distributions. INDICATE quantifies the amount of stellar affiliation of each individual star, and also determines whether this affiliation is above random expectation for the star-forming region in question. We show that INDICATE cannot be used to quantify the overall structure of a region due to a degeneracy when applied to regions with different geometries. We test the ability of INDICATE to detect differences in the local stellar surface density and its ability to detect and quantify mass segregation. We then compare it to other methods such as the mass segregation ratio ${\Lambda }_{\mathrm{MSR}}$, the local stellar surface density ratio ${\Sigma }_{\mathrm{LDR}}$ and the cumulative distribution of stellar positions. INDICATE detects significant differences in the clustering tendencies of the most massive stars when they are at the centre of a smooth, centrally concentrated distribution, corresponding to areas of greater stellar surface density. When applied to a subset of the 50 most massive stars we show INDICATE can detect signals of mass segregation. We apply INDICATE to the following nearby star-forming regions: Taurus, ONC, NGC 1333, IC 348 and $\rho$ Ophiuchi and find a diverse range of clustering tendencies in these regions.

arXiv comment16 pages + appendices, 10 figures, accepted for publication in MNRAS

References in corpus (39)

• Embedded Clusters in Molecular Clouds
• On the fraction of star formation occurring in bound stellar clusters
• The Spatial Distribution of Star Formation in the Solar Neighbourhood: Do all stars form in clusters?
• The statistical Analysis of Star Clusters
• ISOCAM observations of the rho Ophiuchi cloud: Luminosity and mass functions of the pre-main sequence embedded cluster
• Pre-main-sequence isochrones -- II. Revising star and planet formation timescales
• Using the minimum spanning tree to trace mass segregation
• The dynamical evolution of fractal star clusters: the survival of substructure
• Mass segregation and fractal substructure in young massive clusters: (I) the McLuster code and method calibration
• A dynamical origin for early mass segregation in young star clusters
• The early dynamical evolution of cool, clumpy star clusters
• Dynamical evolution of star forming regions
• On the function describing the stellar initial mass function
• Quantitative Evidence for an Intrinsic Age Spread in the Orion Nebula Cluster
• The Spatial Evolution of Stellar Structures in the LMC
• Evolving structures of star-forming clusters
• The spatial distribution of stars in open clusters
• No wide spread of stellar ages in the Orion Nebula Cluster
• Spatial Distributions of Young Stars
• Interpreting the Mean Surface Density of Companions in Star-Forming Regions
• Characterizing the dynamical state of star clusters from snapshots of their spatial distributions
• The Complex Distribution of Recently Formed Stars. Bimodal Stellar Clustering in the Star-Forming Region NGC 346
• Global mass segregation in hydrodynamical simulations of star formation
• Dynamics versus structure: breaking the density degeneracy in star formation
• Comparisons between different techniques for measuring mass segregation
• On the mass segregation of stars and brown dwarfs in Taurus
• Mass segregation and sequential star formation in NGC 2264 revealed by Herschel
• Limits on initial mass segregation in young clusters
• Dynamical evolution of fractal structures in star-forming regions
• On the spatial distributions of dense cores in Orion B
• Dynamical histories of the IC348 and NGC1333 star-forming regions in Perseus
• The Spatial Evolution of Young Massive Clusters I. A New Tool to Quantitatively Trace Stellar Clustering
• Statistical comparison of clouds and star clusters
• A search for mass segregation of stars and brown dwarfs in ρ Ophiuchi
• How fast is mass-segregation happening in hierarchical formed embedded star clusters?
• ${\mathcal{Q}}^{+}$: Characterising the structure of young star clusters
• The Spatial Evolution of Young Massive Clusters II. Looking for Imprints of Star Formation in NGC 2264 with Gaia DR2
• The substructure of the Perseus star forming region: A survey with Gaia DR2
• No preferential spatial distribution for massive stars expected from their formation

Cited by in corpus (7)

• Quantifying kinematic substructure in star-forming regions with statistical tests of spatial autocorrelation
• On the origin of planetary-mass objects in NGC1333
• The Spatial Evolution of Young Massive Clusters III. Effect of the Gaia Filter on 2D Spatial Distribution Studies
• Observational Bias and Young Massive Cluster Characterisation I. 2D Perspective Effects
• Using Molecular Gas Observations to Guide Initial Conditions for Star Cluster Simulations
• Cloud structure and young star distribution in the Dragonfish complex
• Deviations from the universal Initial Mass Function in binary star clusters