The Physical Structure of a Prestellar Core in IC 5146

Carsten Kramer, João Alves, Charles Lada

We observed an evenly sampled map of the 3 P

1-3 P 0 line of neutral atomic carbon

in a 0.5 x 0.5 pc2 quiescent, dark core region of IC 5146

immersed in the interstellar radiation field. For comparison at the same

spatial resolution of 0.067 pc, we mapped in addition the emission of

13CO 2-1, and, previously, of C18O 2-1 and A_V.

The evenly sampled map of A_V was created by Lada et al. [14] from NIR

pencil beam observations towards background stars. We find that C I and

13CO 2-1 line intensities are well correlated reflecting

their similar line shapes. In contrast to C18O, their

integrated intensities stay almost constant with extinctions and are

poorly correlated. We argue that this is indicative of unresolved small

scale structure and use a spherical symmetric model of photon dominated

regions (PDRs) to study the emergent line intensities. The observations

are consistent with a large number of small clumps having radii of e.g.

760 AU, masses of 10-3 M_{⊙} and surface densities of

105 cm-3. The volume filling factor is ˜10%.

Department of Astrophysics
External organisation(s)
European Southern Observatory (Germany), Universität zu Köln, Harvard-Smithsonian Center for Astrophysics
Publication date
Austrian Fields of Science 2012
103004 Astrophysics
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