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THE CHESS SURVEY OFTHE L1157-B1 SHOCKREGION: CO SPECTRALSIGNATURES OFJET-DRIVEN BOW SHOCKS B. LeflóchS. CabritG. Busquet2012 год

THE CHESS SURVEY OF THE L1157-B1 SHOCK REGION: CO SPECTRAL SIGNATURES OF JET-DRIVEN BOW SHOCKS
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Полный текстСтраница публикацииПубликация в OpenAlex
Аннотация: The unprecedented sensitivity of Herschel coupled with the high resolution of the HIFI spectrometer permits studies of the intensity–velocity relationship I(v) in molecular outflows, over a higher excitation range than possible up to now. Over the course of the CHESS Key Program, we have observed toward the bright bow shock region L1157-B1, the CO rotational transitions between J = 5–4 and J = 16–15 with HIFI, and the J = 1–0, 2–1, and 3–2 with the IRAM 30 m and the Caltech Submillimeter Observatory telescopes. We find that all the line profiles ICO(v) are well fit by a linear combination of three exponential laws ∝exp (− |v/v0|) with v0 = 12.5, 4.4, and 2.5 km s−1. The first component dominates the CO emission at J ⩾ 13, as well as the high-excitation lines of SiO and H2O. The second component dominates for 3 ⩽ Jup ⩽ 10 and the third one for Jup ⩽ 2. We show that these exponentials are the signature of quasi-isothermal shocked gas components: the impact of the jet against the L1157-B1 bow shock (Tk ≃ 210 K), the walls of the outflow cavity associated with B1 (Tk ≃ 64 K), and the older cavity L1157-B2 (Tk ≃ 23 K), respectively. Analysis of the CO line flux in the large-velocity gradient approximation further shows that the emission arises from dense gas (n(H2) ⩾ 105–106 cm−3) close to LTE up to J = 20. We find that the CO J = 2–1 intensity–velocity relation observed in various other molecular outflows is satisfactorily fit by similar exponential laws, which may hold an important clue to their entrainment process.
Год издания: 2012
Авторы: B. Leflóch, S. Cabrit, G. Busquet, C. Codella, C. Ceccarelli, J. Cernicharo, J. R. Pardo, M. Benedettini, D. C. Lis, B. Nisini
Издательство: IOP Publishing
Источник: The Astrophysical Journal Letters
Ключевые слова: Astrophysics and Star Formation Studies, Gamma-ray bursts and supernovae, Astrophysical Phenomena and Observations
Другие ссылки: The Astrophysical Journal Letters (HTML)
HAL (Le Centre pour la Communication Scientifique Directe) (HTML)
HAL (Le Centre pour la Communication Scientifique Directe) (HTML)
arXiv (Cornell University) (PDF)
arXiv (Cornell University) (HTML)
CaltechAUTHORS (California Institute of Technology) (PDF)
CaltechAUTHORS (California Institute of Technology) (HTML)
DataCite API (HTML)