Dynamics and PDR properties in IC1396A

TL;DR

This study maps and analyzes the gas dynamics and physical properties of PDRs in IC1396A using multi-line observations, revealing velocity gradients and structural differences among tracers, and comparing results with PDR models.

Contribution

It provides detailed velocity and spatial structure of PDRs in IC1396A through multi-line mapping, enhancing understanding of gas dynamics in illuminated globules.

Findings

[CII] emission shows a velocity gradient within the globule.

[CI] and CO(4-3) emissions peak in different regions.

The gas density is estimated to be between 10^4 and 10^5 cm^-3.

Abstract

We investigate the gas dynamics and the physical properties of photodissociation regions (PDRs) in IC1396A, which is an illuminated bright-rimmed globule with internal structures created by young stellar objects. Our mapping observations of the [CII] emission in IC1396A with GREAT onboard SOFIA revealed the detailed velocity structure of this region. We combined them with observations of the [CI] 3P_1 - 3P_0 and CO(4-3) emissions to study the dynamics of the different tracers and physical properties of the PDRs. The [CII] emission generally matches the IRAC 8 micron, which traces the polycyclic aromatic hydrocarbon (PAH) emissions. The CO(4-3) emission peaks inside the globule, and the [CI] emission is strong in outer regions, following the 8 micron emission to some degree, but its peak is different from that of [CII]. The [CII] emitting gas shows a clear velocity gradient within the globule, which is not significant in the [CI] and CO(4-3) emission. Some clumps that are prominent in [CII] emission appear to be blown away from the rim of the globule. The observed ratios of [CII]/[CI] and [CII]/CO(4-3) are compared to the KOSMA-tau PDR model, which indicates a density of 10^4-10^5 cm-3.