Near-infrared H2 and Continuum Survey of Extended Green Objects
Abstract
The Spitzer GLIMPSE survey has revealed a number of "Extended Green Objects" (EGOs) that display extended emission at 4.5 μm. These EGOs are potential candidates for high-mass protostellar outflows. We used high-resolution (<1'') H2 1-0 S(1) line, K-, and H-band images from the United Kingdom Infrared Telescope to study 34 EGOs to investigate their nature. We found that 12 EGOs exhibit H2 outflows (two with chains of H2 knotty structures, five with extended H2 bipolar structures, three with extended H2 lobes, and two with pairs of H2 knots). Of the 12 EGOs with H2 outflows, three exhibit similar morphologies between the 4.5 μm and H2 emission. However, the remaining nine EGOs show that the H2 features are more extended than the continuum features, and the H2 emission is seldom associated with continuum emission. Furthermore, the morphologies of the near-infrared continuum and 4.5 μm emission are similar to each other for those EGOs with K-band emission, implying that at least part of the IRAC-band continuum emission of EGOs comes from scattered light from the embedded young stellar objects.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- May 2012
- DOI:
- 10.1088/0067-0049/200/1/2
- arXiv:
- arXiv:1203.2416
- Bibcode:
- 2012ApJS..200....2L
- Keywords:
-
- ISM: jets and outflows;
- stars: formation;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- accepted for publication in ApJS