Investigating the structure and fragmentation of a highly filamentary IRDC

2016/07/28 by J. D. Henshaw, Jonathan D. Henshaw, P. Caselli +11 · 2 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics #Astrophysics and Star Formation Studies #Atmospheric Ozone and Climate #Fragmentation (computing) #Galaxy #Infrared #Optics #Physics #Star formation #Stars #Stellar, planetary, and galactic studies #Substructure #Virial theorem #astro-ph.GA

paper · pdf · doi:10.1093/mnras/stw1794

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)

openalex publication_date 2016/07/28 · arxiv created 2016/08/15 · arxiv updated 2016/08/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

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 (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 emphasises 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 rm x10²³ rm cm^-2<N_H,c<8.0 rm x10²³ rm cm^-2), mass (8.1M _odot<M_c<26.1M _odot), and number density (6.1 rm x10⁵ rm cm^-3<n_{H, c, eq}<14.7 rm x10⁵ rm 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 ~20-25M _odot, are good candidates for the progenitors of intermediate-to-high-mass stars. Virial parameters span a range 0.2<\α _{rm vir}<1.3. Without additional support, possibly from dynamically important magnetic fields with strengths of the order 230\μG<B<670\μG, the cores are susceptible to gravitational collapse. These results may imply a multi-layered fragmentation process, which incorporates the formation of sub-filaments, embedded cores, and the possibility of further fragmentation.

Citations

• Mid-JCO shock tracing observations of infrared dark clouds. I.
• Herschelview of the large-scale structure in the Chamaeleon dark clouds
• A SPITZER SURVEY OF YOUNG STELLAR CLUSTERS WITHIN ONE KILOPARSEC OF THE SUN: CLUSTER CORE EXTRACTION AND BASIC STRUCTURAL ANALYSIS
• Identifying Primordial Substructure in NGC 2264
• Shortest Connection Networks And Some Generalizations
• A Molecular Line Observation toward Massive Clumps Associated with Infrared Dark Clouds
• Chains of dense cores in the Taurus L1495/B213 complex
• Star Formation in Molecular Clouds: Observation and Theory
• A new look at the statistical model identification
• Ionizing feedback from massive stars in massive clusters: fake bubbles and untriggered star formation
• Mid-JCO shock tracing observations of infrared dark clouds
• Probing the initial conditions of high-mass star formation II : Fragmentation, stability, and chemistry towards high-mass star-forming regions G29.96-0.02 and G35.20-1.74

Cited by

• Gravity drives the evolution of infrared dark hubs: JVLA observations of SDC13
• Filamentary Fragmentation and Accretion in High-mass Star-forming Molecular Clouds