ASIAA Summer Student Program 2009
1 Jul. - 31 Aug., 2009 at ASIAA, Taipei
Studying the Nature of Extended Green Objects [CFHT and Optical/Infrared Related Projects]
Dr. Hsu-Tai Lee, Dr. Sheng-Yuan Liu, and Dr. Yu-Nung Su
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Task Description and Goals
Extended Green Objects (EGOs) have been recently identified as new outflow candidates from Massive Young Stellar Objects (MYSOs). They exhibit extended 4.5 micron emission probably coming from shock-excited molecular Hydrogen and/or CO in the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE). In Spitzer images, the majority of EGOs show irregular shapes, although some of them look elongated (angular extents range from a few to more than 30"). Most of the EGOs are associated with infrared dark clouds and methanol masters likely relate to massive star formation.
The real nature of EGOs is still unknown, and other wavelengths are crucial to understanding these sources. The GLIMPSE survey provided a wealthy sample of MYSO outflows candidates, but a detailed study of their morphologies can not be achieved with ~2" Spitzer resolution. Most previous studies of outflows from MYSOs were used mm or submm inteferometries. This project provides an independent way to study these outflow candidates in infrared. We would like to use archive data (2MASS and UKIDSS with ~1" resolution) to investigate the nature of EGOs.