Dynamics and photodissociation region properties in IC 1396A
Y. Okada1, R. Güsten2, M. A. Requena-Torres2, M. Röllig1, P. Hartogh3, H.-W. Hübers4,5, T. Klein2, O. Ricken1, R. Simon1 and J. Stutzki1
1 I. Physikalisches Institut der Universität zu Köln, Zülpicher Straße 77, 50937 Köln, Germany
2 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
3 Max-Planck-Institut für Sonnensystemforschung, Max-Planck-Straße 2, 37191 Katlenburg-Lindau, Germany
4 Deutsches Zentrum für Luft- und Raumfahrt, Institut für Planetenforschung, Rutherfordstraße 2, 12489 Berlin, Germany
5 Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
Received: 30 January 2012
Accepted: 2 March 2012
Aims. We investigate the gas dynamics and the physical properties of photodissociation regions (PDRs) in IC 1396A, which is an illuminated bright-rimmed globule with internal structures created by young stellar objects.
Methods. Our mapping observations of the [C ii] emission in IC 1396A with GREAT onboard SOFIA revealed the detailed velocity structure of this region. We combined them with observations of the [C i] 3P1−3P0 and CO(4–3) emissions to study the dynamics of the different tracers and physical properties of the PDRs.
Results. The [C ii] emission generally matches the IRAC 8 μm, which traces the polycyclic aromatic hydrocarbon (PAH) emissions. The CO(4–3) emission peaks inside the globule, and the [C i] emission is strong in outer regions, following the 8 μm emission to some degree, but its peak is different from that of [C ii]. The [C ii] emitting gas shows a clear velocity gradient within the globule, which is not significant in the [C i] and CO(4–3) emission. Some clumps that are prominent in [C ii] emission appear to be blown away from the rim of the globule. The observed ratios of [C ii]/[C i] and [C ii]/CO(4–3) are compared to the KOSMA-τ PDR model, which indicates a density of 104–105 cm-3.
Key words: ISM: lines and bands / photon-dominated region (PDR) / ISM: individual objects: IC 1396
© ESO, 2012