Sökning: WFRF:(Tafalla M.) >
Water emission from...
Water emission from the chemically rich outflow L1157
-
- Vasta, M. (författare)
- Osservatorio Astrofisico di Arcetri,Arcetri Astrophysical Observatory
-
- Codella, C. (författare)
- Osservatorio Astrofisico di Arcetri,Arcetri Astrophysical Observatory
-
- Lorenzani, A. (författare)
- Osservatorio Astrofisico di Arcetri,Arcetri Astrophysical Observatory
-
visa fler...
-
- Santangelo, G. (författare)
- Osservatorio Astronomico di Roma
-
- Nisini, B. (författare)
- Osservatorio Astronomico di Roma
-
- Giannini, T. (författare)
- Osservatorio Astronomico di Roma
-
- Tafalla, M. (författare)
- Observatorio Astronómico Nacional (OAN),Spanish National Observatory (OAN)
-
- Liseau, René, 1949 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
-
- van Dishoeck, E. F. (författare)
- Max Planck Gesellschaft zur Förderung der Wissenschaften e.V. (MPG),Max Planck Society for the Advancement of Science (MPG),Universiteit Leiden (UL),Leiden University (UL)
-
- Kristensen, L. (författare)
- Universiteit Leiden (UL),Leiden University (UL)
-
visa färre...
-
(creator_code:org_t)
- 2012-01-16
- 2012
- Engelska.
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 537, s. Article Number: A98 -
- Relaterad länk:
-
http://publications.... (primary) (free)
-
visa fler...
-
http://arxiv.org/pdf...
-
https://doi.org/10.1...
-
https://research.cha...
-
visa färre...
Abstract
Ämnesord
Stäng
- Context. In the framework of the Herschel-WISH key program, several ortho-H2O and para-H2O emission lines, in the frequency range from 500 to 1700 GHz, were observed with the HIFI instrument in two bow-shock regions (B2 and R) of the L1157 cloud, which hosts what is considered to be the prototypical chemically-rich outflow. Aims. Our primary aim is to analyse water emission lines as a diagnostic of the physical conditions in the blue (B2) and red-shifted (R) lobes to compare the excitation conditions. Methods. For this purpose, we ran the non-LTE RADEX model for a plane-parallel geometry to constrain the physical parameters (T-kin, N-H2O and nH(2)) of the water emission lines detected. Results. A total of 5 ortho- and para-(H2O)-O-16 plus one o-(H2O)-O-18 transitions were observed in B2 and R with a wide range of excitation energies (27K = 300 K). The presence of the broad red-shifted wings and multiple peaks in the spectra of the R region, prompted the modelling of two components. High velocities are associated with relatively low temperatures (similar to 100 K), N-H2O similar or equal to 5 x 10(12)-5 x 10(13) cm(-2) and densities nH(2) similar or equal to 10(6)-10(8) cm(-3). Lower velocities are associated with higher excitation conditions with T-kin >= 300 K, very dense gas (nH(2) similar to 10(8) cm(-3)) and low column density (N-H2O = 15 '') region, whilst we cannot rule out the possibility that the emission in R arises from a smaller (>3 '') region. In this context, H2O seems to be important in tracing different gas components with respect to other molecules, e.g. such as SiO, a classical jet tracer. We compare a grid of C-and J-type shocks spanning different velocities (10 to 40 km s(-1)) and two pre-shock densities (2 x 10(4) and 2 x 10(5) cm(-3)), with the observed intensities. Although none of these models seem to be able to reproduce the absolute intensities of the water emissions observed, it appears that the occurrence of J-shocks, which can compress the gas to very high densities, cannot be ruled out in these environments.
Ämnesord
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Nyckelord
- sio
- magnetohydrodynamic shock-waves
- h-2
- excitation
- ISM: molecules
- program
- clouds
- ammonia
- chess spectral
- molecular outflow
- stars: formation
- star-forming regions
- ISM: jets and outflows
- stars
- low-mass
- survey
- stars: individual: L1157
Publikations- och innehållstyp
- art (ämneskategori)
- ref (ämneskategori)
Hitta via bibliotek
Till lärosätets databas
- Av författaren/redakt...
-
Vasta, M.
-
Codella, C.
-
Lorenzani, A.
-
Santangelo, G.
-
Nisini, B.
-
Giannini, T.
-
visa fler...
-
Tafalla, M.
-
Liseau, René, 19 ...
-
van Dishoeck, E. ...
-
Kristensen, L.
-
visa färre...
- Om ämnet
-
- NATURVETENSKAP
-
NATURVETENSKAP
-
och Fysik
-
och Astronomi astrof ...
- Artiklar i publikationen
-
Astronomy and As ...
- Av lärosätet
-
Chalmers tekniska högskola