Science China Physics, Mechanics & Astronomy

, Volume 58, Issue 2, pp 1–11 | Cite as

350 μm map of the Ophiuchus molecular cloud: core mass function

  • GuoYin Zhang
  • Di LiEmail author
  • Ashley K. Hyde
  • Lei Qian
  • HuaLei Lyu
  • ZhongZu Wu
Article Star and Galactic System


Stars are born in dense cores of molecular clouds. The core mass function (CMF), which is the mass distribution of dense cores, is important for understanding the stellar initial mass function (IMF). We obtained 350 μm dust continuum data using the SHARC-II camera at the Caltech Submillimeter Observatory (CSO) telescope. A 350 μm map covering 0.25 deg2 of the Ophiuchus molecular cloud was created by mosaicing 56 separate scans. The CSO telescope had an angular resolution of 9″, corresponding to 1.2 × 103 AU at the distance of the Ophiuchus molecular cloud (131 pc). The data was reduced using the Comprehensive Reduction Utility for SHARC-II (CRUSH). The flux density map was analyzed using the GaussClumps algorithm, within which 75 cores has been identified. We used the Spitzer c2d catalogs to separate the cores into 63 starless cores and 12 protostellar cores. By locating Jeans instabilities, 55 prestellar cores (a subcategory of starless cores) were also identified. The excitation temperatures, which were derived from FCRAO 12CO data, help to improve the accuracy of the masses of the cores. We adopted a Monte Carlo approach to analyze the CMF with two types of functional forms; power law and log-normal. The whole and prestellar CMF are both well fitted by a log-normal distribution, with µ = −1.18 ± 0.10, σ = 0.58 ± 0.05 and µ = 1.40 ± 0.10, σ = 0.50 ± 0.05 respectively. This finding suggests that turbulence influences the evolution of the Ophiuchus molecular cloud.


ISM molecular clouds Ophiuchus CMF 


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Copyright information

© Science China Press and Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • GuoYin Zhang
    • 1
    • 2
  • Di Li
    • 2
    • 3
    • 4
    • 5
    Email author
  • Ashley K. Hyde
    • 6
  • Lei Qian
    • 3
  • HuaLei Lyu
    • 3
  • ZhongZu Wu
    • 1
  1. 1.College of Science/Department of PhysicsGuizhou UniversityGuiyangChina
  2. 2.Key Laboratory of Radio AstronomyChinese Academy of SciencesNanjingChina
  3. 3.National Astronomical ObservatoriesChinese Academy of SciencesBeijingChina
  4. 4.Space Science InstituteBoulderUSA
  5. 5.Department of AstronomyCalifornia Institute of TechnologyPasadenaUSA
  6. 6.Astrophysics Group, Imperial College LondonBlackett LaboratoryLondonUK

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