Observations and analysis of water in molecular outflows and shocks

University dissertation from Chalmers University of Technology

Abstract: This thesis describes observations and analysis of molecular out?ows from young stellar objects. The observations using the Odin satellite are described in Paper I, where a non-LTE radiative transfer code has been used to estimate the ortho-water abundance in seven molecular out?ows and one super-nova remnant. Elevated abundances are found in several sources, as expected in continuous type shocks. Also a correlation between the maximum out?ow velocity and the abundance is found. Complementary observations of formyl (HCO+) have been carried out with the Onsala 20 meter antenna. A correlation between formyl and water has previously been observed towards continuum sources in the Milky Way and for that reason we make observations of the sources observed with Odin and proposed for the Herschel Space Observatory. An Accelerated Lamda Iteration code (ALI) is used to obtain information from observed line pro?les. Varying the ortho-water abundance, line pro?les are computed for various gas densities and kinetic temperatures. For the source HH54 B, observations of CO and H2O have been made using Odin, SEST and Herschel. A simple model of a curved bowshock ?ts the observations reasonably well and enables us to determine the kinetic temperature and the density of the source. The ALI code is also used to make predictions for the forthcoming observations with Herschel.

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