Investigating the structure and fragmentation of a highly filamentary IRDC

Abstract

We present 3.7 arcsec (~0.05 pc) resolution 3.2 mm dust continuum observations from the IRAM PdBI, with the aim of studying the structure and fragmentation of the filamentary Infrared Dark Cloud G035.39-00.33. The continuum emission is segmented into a series of 13 quasi-regularly spaced (~0.18pc) cores, following the major axis of the IRDC. We compare the spatial distribution of the cores with that predicted by theoretical work describing the fragmentation of hydrodynamic fluid cylinders, finding a significant (a factor of ~8) discrepancy between the two. Our observations are consistent with the picture emerging from kinematic studies of molecular clouds suggesting that the cores are harboured within a complex network of independent sub-filaments. This result emphasizes the importance of considering the underlying physical structure, and potentially, dynamically important magnetic fields, in any fragmentation analysis. The identified cores exhibit a range in (peak) beam-averaged column density ($3.6\mathrm{x}10^{23}{\mathrm{cm}}^{-2}<N_{H,c}<8.0\mathrm{x}10^{23}{\mathrm{cm}}^{-2}$), mass ($8.1M_{\odot }<M_c<26.1M_{\odot }$), and number density ($6.1\mathrm{x}10^5{\mathrm{cm}}^{-3}<n_{H,c,eq}<14.7\mathrm{x}10^5{\mathrm{cm}}^{-3}$). Two of these cores, dark in the mid-infrared, centrally-concentrated, monolithic (with no traceable substructure at our PdBI resolution), and with estimated masses of the order ~20-25$M_{\odot }$, are good candidates for the progenitors of intermediate-to-high-mass stars. Virial parameters span a range $0.2<{\alpha }_{\mathrm{vir}}<1.3$. Without additional support, possibly from dynamically important magnetic fields with strengths of the order 230$\mu$G<B<670$\mu$G, the cores are susceptible to gravitational collapse. These results may imply a multilayered fragmentation process, which incorporates the formation of sub-filaments, embedded cores, and the possibility of further fragmentation.

14 pages (plus 10 page appendix), 6 figures (plus 11 in appendix), 3 tables. Accepted for publication in MNRAS. Abstract modified due to character limit. This updated version includes minor corrections (including typos and updated references)

References in corpus (28)

• A Spitzer Survey of Young Stellar Clusters within One Kiloparsec of the Sun: Cluster Core Extraction and Basic Structural Analysis
• Structural Analysis of Molecular Clouds: Dendrograms
• Filamentary structure of star-forming complexes
• A Catalog of Extended Green Objects (EGOs) in the GLIMPSE Survey: A new sample of massive young stellar object outflow candidates
• Bias-free Measurement of Giant Molecular Cloud Properties
• Using the minimum spanning tree to trace mass segregation
• Magnetic Fields in High-Mass Infrared Dark Clouds
• Fragmentation of Molecular Clumps and Formation of Protocluster
• The Fragmentation of Magnetized, Massive Star-Forming Cores with Radiative Feedback
• Chains of dense cores in the Taurus L1495/B213 complex
• The dynamical properties of dense filaments in the infrared dark cloud G035.39-00.33
• The Perils of Clumpfind: The Mass Spectrum of Sub-structures in Molecular Clouds
• CARMA Large Area Star Formation Survey: Observational Analysis of Filaments in the Serpens South Molecular Cloud
• Complex, Quiescent Kinematics in a Highly Filamentary Infrared Dark Cloud
• Understanding star formation in molecular clouds II. Signatures of gravitational collapse of IRDCs
• VLA observations of ammonia in high-mass star formation regions
• A Molecular Line Observation toward Massive Clumps Associated with Infrared Dark Clouds
• Submillimeter Array Observations of Magnetic Fields in G240.31+0.07: an Hourglass in a Massive Cluster-forming Core
• Herschel's view of the large-scale structure in the Chamaeleon dark clouds
• CARMA Large Area Star Formation Survey: Structure and Kinematics of Dense Gas in Serpens Main
• Unveiling the Early-Stage Anatomy of a Protocluster Hub with ALMA
• SiO emission from low- and high-velocity shocks in Cygnus-X massive dense clumps
• The Onset of Massive Star Formation: The Evolution of Temperature and Density Structure in an Infrared Dark Cloud
• Distributed Low-Mass Star Formation in the IRDC G34.43+00.24
• Initial Fragmentation in the Infrared Dark Cloud G28.53-0.25
• Shaping a high-mass star-forming cluster through stellar feedback. The case of the NGC 7538 IRS 1-3 complex
• Fragmentation and Kinematics of dense molecular cores in the filamentary infrared-dark cloud G011.11-0.12
• Mid-J CO Shock Tracing Observations of Infrared Dark Clouds I

Cited by in corpus (28)

• A closer look at the "characteristic" width of molecular cloud filaments
• The central 1000 AU of a pre-stellar core revealed with ALMA. I. 1.3 mm continuum observations
• Ubiquitous velocity fluctuations throughout the molecular interstellar medium
• Unveiling the Early-Stage Anatomy of a Protocluster Hub with ALMA
• Interstellar filaments and star formation
• Young massive star cluster formation in the Galactic Centre is driven by global gravitational collapse of high-mass molecular clouds
• ALMA-IRDC: Dense gas mass distribution from cloud to core scales
• Temperature structure and kinematics of the IRDC G035.39-00.33
• Mother of Dragons: A Massive, quiescent core in the dragon cloud (IRDC G028.37+00.07)
• The hierarchical fragmentation of filaments and the role of sub-filaments
• CMZoom II: Catalog of Compact Submillimeter Dust Continuum Sources in the Milky Way's Central Molecular Zone
• Accretion driven turbulence in filaments II: Effects of self-gravity
• Determining the presence of characteristic fragmentation length-scales in filaments
• OGHReS: Large-scale filaments in the outer Galaxy
• Gravitational instability of filamentary molecular clouds, including ambipolar diffusion
• Probing the massive star forming environment - a multiwavelength investigation of the filamentary IRDC G333.73+0.37
• Molecular Gas Structures traced by ${}^{13}$CO Emission in the 18,190 ${}^{12}$CO Molecular Clouds from the MWISP Survey
• High-Mass Starless Clumps: Dynamical State and Correlation Between Physical Parameters
• Filament Intersections and Cold Dense Cores in Orion A North
• The initial conditions for young massive cluster formation in the Galactic Centre: convergence of large-scale gas flows
• Star formation in IRDC G31.97+0.07
• Deuterium fractionation of a distant cold dark cloud along the line of sight of W51
• The warm and dense Galaxy - tracing the formation of dense cloud structures out to the Galactic Center
• ArTéMiS imaging of the filamentary infrared dark clouds G1.75-0.08 and G11.36+0.80: Dust-based physical properties of the clouds and their clumps
• What did the seahorse swallow? APEX 170 GHz observations of the chemical conditions in the Seahorse infrared dark cloud
• An X-ray View of Two Infrared Dark Clouds G034.43+00.24 and G035.39-00.33
• SiO emission in the filamentary Infrared Dark Cloud G035.39-00.33: An ALMA view
• Drifters on the edge of town: $\lambda$ Boötis stars in clusters