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Title: The identification of filaments on far-infrared and submillimiter images: Morphology, physical conditions and relation with star formation of filamentary structure

Observations of molecular clouds reveal a complex structure, with gas and dust often arranged in filamentary, rather than spherical geometries. The association of pre- and proto-stellar cores with the filaments suggests a direct link with the process of star formation. Any study of the properties of such filaments requires representative samples from different environments for an unbiased detection method. We developed such an approach using the Hessian matrix of a surface-brightness distribution to identify filaments and determine their physical and morphological properties. After testing the method on simulated, but realistic, filaments, we apply the algorithms to column-density maps computed from Herschel observations of the Galactic plane obtained by the Hi-GAL project. We identified ∼500 filaments, in the longitude range of l = 216.°5 to l = 225.°5, with lengths from ∼1 pc up to ∼30 pc and widths between 0.1 pc and 2.5 pc. Average column densities are between 10{sup 20} cm{sup –2} and 10{sup 22} cm{sup –2}. Filaments include the majority of dense material with N{sub H{sub 2}} > 6 × 10{sup 21} cm{sup –2}. We find that the pre- and proto-stellar compact sources already identified in the same region are mostly associated with filaments. However, surface densities inmore » excess of the expected critical values for high-mass star formation are only found on the filaments, indicating that these structures are necessary to channel material into the clumps. Furthermore, we analyze the gravitational stability of filaments and discuss their relationship with star formation.« less
Authors:
; ;  [1] ;  [2] ; ; ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] ;  [11]
  1. Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)
  2. European Space Research and Technology Centre (ESA-ESTEC), Keplerlaan 1, P.O. Box 299, 2200 AG Noordwijk (Netherlands)
  3. Istituto di Astrofisica e Planetologia Spaziali, INAF-IAPS, Via Fosso del Cavaliere 100, I-00133 Roma (Italy)
  4. Instituto de Astrofísica de Andalucia, CSIC, Glorieta de la Astronomía, s/n, E-18008, Granada (Spain)
  5. Departement of Astrophysics, Astronomy and Mechanics, Faculty of Physics, University of Athens, Panepistimiopolis, 15784 Zografos, Athens (Greece)
  6. Instituto de RadioAstronomía Milimétrica Avenida Divina Pastora, 7, Núcleo Central, E-18012 Granada (Spain)
  7. Space Telescope Science Institute, Baltimore, MD 21218 (United States)
  8. Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom)
  9. Department of Physics and Astronomy and the Institute for Space Imaging Sciences, University of Calgary, Calgary, AB T2N IN4 (Canada)
  10. Zentrüm für Astronomie, Institut für Theoretische Astrophysik, Universität Heidelberg, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany)
  11. Centro de Radioastronomía y Astrofísica (CRyA), Universidad Nacional Autónoma de México, CP 58190 Morelia, Michoacán (Mexico)
Publication Date:
OSTI Identifier:
22365395
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 791; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ALGORITHMS; BRIGHTNESS; DATA ANALYSIS; DENSITY; DETECTION; DISTRIBUTION; IMAGES; MASS; SIMULATION; SPHERICAL CONFIGURATION; STABILITY; STARS; SURFACES; TESTING