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| EPoS Contribution |
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FIR lines from Herschel cores: state of the molecular and atomic gas
Hendrik Linz MPIA Heidelberg, Heidelberg, Germany | |
| The properties of very young star-forming cores are difficult to trace. Many of their physical parameters still need to be refined observationally, before a meaningful modelling can advance. The Herschel satellite has provided access to the wavelength regime where the bulk of emission arises for such objects. As a spin-off of our EPOS Herschel Key programme, we employed the two versatile spectrographs SPIRE-FTS and PACS-Spec in order to scrutinise eleven very young protostars from the EPOS sample. These comprise a large range of masses and luminosities and feature low-mass Class-0 protostars as well as higher-mass cores embedded in IRDCs. In this contribution, we show first results of this programme. We recover emission from molecular species like CO and HCO+ (and occasionally CH+ in absorption) with SPIRE-FTS, which in combination with ground-based data enables an excitation analysis. In some objects, the data reveal activity and higher-temperature gas that escaped our attention when solely relying on ground-based data of the lower transitions. With the PACS spectroscopy for a sub-sample of objects we trace the most important cooling lines of oxygen, carbon, and water to assess the thermal budget for these object stages. Interestingly, the [CII] and [OI] lines seem to appear in absorption toward the continuum peaks of our PACS targets. We discuss the interpretation of these findings and what they imply for the temperature and density structure of the cores in comparison to the natal clump envelopes. | |
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| Caption: SPIRE FTS-LW spectrum towards the active outflow-driving core 3 within the IRDC 18223. Main emission lines are marked, and a number of smaller bumps and wiggles hide some more frail tracers like 13CO, HCO+, H2O, and CH+ absorption. | |
| Collaborators: H. Beuther, MPIA, Germany S. Ragan, MPIA, Germany A. Stutz, MPIA, Germany Th. Henning, MPIA, Germany |
Suggested Session:
Cores |