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تسجيل مستخدم جديدALMA discovery of a dual dense probably rotating outflow from a massive young stellar object G18.88MME
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تأليف
I. I. Zinchenko
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We report the discovery of a very dense jet-like fast molecular outflow surrounded by a wide-angle wind in a massive young stellar object (MYSO) G18.88MME (stellar mass $sim$8 M$_{odot}$) powering an Extended Green Object G18.89$-$0.47. Four cores MM1-4 are identified in the Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm continuum map (resolution $sim$0.$$8) toward G18.88MME, and are seen at the center of the emission structure (extent $sim$0.3 pc $times$ 0.2 pc) detected in the ALMA map. G18.88MME is embedded in the core MM1 (mass $sim$13-18 M$_{odot}$), where no radio continuum emission is detected. The molecular outflow centered at MM1 is investigated in the SiO(5-4), HC$_{3}$N(24-23) and $^{13}$CO(2-1) lines. The detection of HC$_{3}$N in the outflow is rare in MYSOs and indicates its very high density. The position-velocity diagrams display a fast narrow outflow (extent $sim$28000 AU) and a slower wide-angle more extended outflow toward MM1, and both of these components show a transverse velocity gradient indicative of a possible rotation. All these observed features together make G18.88MME as a unique object for studying the unification of the jet-driven and wind-driven scenarios of molecular outflows in MYSOs.
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