English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The unprecedented sensitivity of Herschel coupled with the high resolution ofthe HIFI spectrometer permits studies of the intensity-velocity relationshipI(v) in molecular outflows, over a higher excitation range than possible up tonow. In the course of the CHESS Key Program, we have observed toward the brightbowshock region L1157-B1 the CO rotational transitions between J=5-4 andJ=16-15 with HIFI, and the J=1-0, 2-1 and 3-2 with the IRAM-30m and the CSOtelescopes. We find that all the line profiles I_{CO}(v) are well fit by alinear combination of three exponential laws exp(-|v/v_0|) with v_0= 12.5, 4.4and 2.5km/s. The first component dominates the CO emission at J_up > 13, aswell as the high-excitation lines of SiO and H2O. The second componentdominates for 3 < J_up < 10 and the third one for J_up < 2. We show that theseexponentials are the signature of quasi-isothermal shocked gas components: theimpact of the jet against the L1157-B1 bowshock (T= 210K), the walls of theoutflow cavity associated with B1 (T= 64K) and the older cavity L1157-B2 (T=23K), respectively. Analysis of the CO line flux in the Large-Velocity Gradientapproximation further shows that the emission arises from dense gas (n(H2) >1e5-1e6 cm-3) close to LTE up to J=20. We find that the CO J=2-1intensity-velocity relation observed in various other molecular outflows issatisfactorily fit by similar exponential laws, which may hold an importantclue to their entrainment process.

The CHESS survey of the L1157-B1 shock region: CO spectral signatures of jet-driven bowshocks