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Title: Statistics of YSO jets in the galactic plane from UWISH2
Author: Ionnidis , G.
Awarding Body: University of Kent
Current Institution: University of Kent
Date of Award: 2013
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In order to study jets and outflows from Young Stellar Objects (YSOs), I performed an unbiased search on a continuous 33 square degree sized region in Serpens and Aquila using data taken from the UWISH2 survey, which uses the 1-0 S(I) emission line ofH2 as a tracer. I identified 130 molecular hydrogen outflows from YSOs from which 120 (92 %) objects are new discoveries. Distances were measured by foreground star counts with an accuracy of25 %. Outflows were found in groups of 3 - 5 members with a size of about 5 pc. Groups were separated by about half a degree on the sky. About half of the objects were assigned with potential source candidates. Brighter MHOs had a higher probability to have a source candidate assigned to them. I find an over abundance of outflows with position angles between 1300 and 1500 which is almost perpendicular to the Galactic Plane. The fraction of parsec scale outflows is about 25 % which is more than twice compared to the one found in Orion A by Stanke et al. (2002) and Davis et al. (2009). The outflows are not able to provide a sufficient fraction of energy and momentum to support the turbulence levels in their surrounding molecular clouds. The typical dynamical jet age was of the order of 104 yrs, while groups of emission knots are ejected every 103 yrs. This indicates that low level accretion rate fluctuations and not Fu-Ori type events are responsible for the episodic ej ection of material. The luminosity distribution of the outflows shows a power law behaviour with N ex: LH;·9. The Milky Way star formation rate was estimated to more than 1.6 ± 0.4M0 yr-1 The Spectral Index Classification distribution plot of YSOs indicated that the number of outflows increases in line with a values and has a similar distribution to the one from Davis et al. (2009) from Orion A.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Young stellar objects, YSOs, Star counts