Deep near-infrared imaging of W3 Main: constraints on stellar cluster formation

Abstract

Embedded clusters like W3 Main are complex and dynamically evolving systems that represent an important phase of the star formation process. We aim at the characterization of the entire stellar content of W3 Main in a statistical sense to identify possible differences in evolutionary phase of the stellar populations and find clues about the formation mechanism of this massive embedded cluster. Methods. Deep JHKs imaging is used to derive the disk fraction, Ks-band luminosity functions and mass functions for several subregions in W3 Main. A two dimensional completeness analysis using artificial star experiments is applied as a crucial ingredient to assess realistic completeness limits for our photometry. We find an overall disk fraction of 7.7 $\pm$ 2.3%, radially varying from 9.4 $\pm$ 3.0 % in the central 1 pc to 5.6 $\pm$ 2.2 % in the outer parts of W3 Main. The mass functions derived for three subregions are consistent with a Kroupa and Chabrier mass function. The mass function of IRSN3 is complete down to 0.14 Msun and shows a break at M $\sim$ 0.5 Msun. We interpret the higher disk fraction in the center as evidence for a younger age of the cluster center. We find that the evolutionary sequence observed in the low-mass stellar population is consistent with the observed age spread among the massive stars. An analysis of the mass function variations does not show evidence for mass segregation. W3 Main is currently still actively forming stars, showing that the ionizing feedback of OB stars is confined to small areas ($\sim$ 0.5 pc). The FUV feedback might be influencing large regions of the cluster as suggested by the low overall disk fraction.

15 pages, 13 figures, accepted by A&A

References in corpus (12)

• A Spitzer Survey of Young Stellar Clusters within One Kiloparsec of the Sun: Cluster Core Extraction and Basic Structural Analysis
• The SCUBA Legacy Catalogue: Continuum Objects Detected by SCUBA
• Dynamical mass segregation on a very short timescale
• A Spitzer view of protoplanetary disks in the gamma Velorum cluster
• The Initial Mass Function of the Massive Star-forming Region NGC 3603 from Near-Infrared Adaptive Optics observations
• Variations in Stellar Clustering with Environment: Dispersed Star Formation and the Origin of Faint Fuzzies
• Understanding Spatial and Spectral Morphologies of Ultracompact H II Regions
• Intermediate to low-mass stellar content of Westerlund 1
• The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds.X. The Chamaeleon II Pre-Main Sequence Population as Observed With IRAC and MIPS
• The Diverse Stellar Populations of the W3 Star Forming Complex
• The star-forming content of the W3 giant molecular cloud
• Herschel Observations of the W3 GMC: Clues to the Formation of Clusters of High-Mass Stars

Cited by in corpus (22)

• Studying the YMC population of M83: how long clusters remain embedded, their interaction with the ISM and implications for GC formation theories
• How can young massive clusters reach their present-day sizes?
• Core-Halo Age Gradients and Star Formation in the Orion Nebula and NGC~2024 Young Stellar Clusters
• Panchromatic Hubble Andromeda Treasury XII. Mapping Stellar Metallicity Distributions in M31
• Star Formation Across the W3 Complex
• Formation of Very Young Massive Clusters and implications for globular clusters
• Dispersal timescale of protoplanetary disks in the low-metallicity young cluster Dolidze 25
• The Discovery of a Very Massive Star in W49
• Deep near-infrared adaptive optics observations of a young embedded cluster at the edge of the RCW 41 HII region
• The Compact Star-Forming Complex at the Heart of NGC 253
• The Massive Stellar Population of W49: A Spectroscopic Survey
• Interaction Between HII Region and AFGL333-Ridge: Implications to the Star Formation Scenario
• Near-infrared spectroscopy of the massive stellar population of W51: evidence for multi-seeded star formation
• Stellar populations in star clusters
• Young Stellar Populations in MYStIX Star Forming Regions: Candidate Protostars
• The young stellar content of the giant HII regions M8, G333.6-0.2, and NGC6357 with VLT/KMOS
• IRAS 09002-4732: A Laboratory for the Formation of Rich Stellar Clusters
• The Panchromatic Hubble Andromeda Treasury. Progression of Large-Scale Star Formation across Space and Time in M31
• The Initial Mass Function of Low-mass Stars and Brown Dwarfs in the W3 Complex
• Evolution of magnetized hub-filament systems: Comparing the observed properties of W3(OH), W3 Main, and S 106
• Near-Infrared Spectroscopy of Ultracompact \ion{H}{2} regions in W51A with NIFS/ALTAIR
• NGC 3105: A Young Cluster in the Outer Galaxy