TY - JOUR
T1 - Methanol maser emission from galactic center sources with excess 4.5 μm emission
AU - Chambers, E. T.
AU - Yusef-Zadeh, F.
AU - Roberts, D.
PY - 2011/5/20
Y1 - 2011/5/20
N2 - We present a study of signatures of on-going star formation in a sample of protostellar objects with enhanced 4.5 μm emission ("green" sources) near the Galactic center. To understand how star formation in the Galactic center region compares to that of the Galactic disk, we used the Expanded Very Large Array to observe radiatively excited ClassII 6.7GHz CH 3OH masers and collisionally excited ClassI 44GHz CH3OH masers, both tracers of high-mass star formation, toward a sample of 34 Galactic center and foreground "green" sources. We find that 33% ± 15% of Galactic center sources are coincident with 6.7GHz masers, and that 44% ± 17% of foreground sources are coincident with 6.7GHz masers. For 44GHz masers, we find correlation rates of 27% ± 13% and 25% ± 13% for Galactic center green sources and foreground green sources, respectively. Based on these CH3OH maser detection rates, as well as correlations of green sources with other tracers of star formation, such as 24 μm emission and infrared dark clouds (IRDCs), we find no significant difference between the green sources in the Galactic center and those foreground to it. This suggests that once the star formation process has begun, the environmental differences between the Galactic center region and the Galactic disk have little effect on its observational signatures. We do find, however, some evidence that may support a recent episode of star formation in the Galactic center region.
AB - We present a study of signatures of on-going star formation in a sample of protostellar objects with enhanced 4.5 μm emission ("green" sources) near the Galactic center. To understand how star formation in the Galactic center region compares to that of the Galactic disk, we used the Expanded Very Large Array to observe radiatively excited ClassII 6.7GHz CH 3OH masers and collisionally excited ClassI 44GHz CH3OH masers, both tracers of high-mass star formation, toward a sample of 34 Galactic center and foreground "green" sources. We find that 33% ± 15% of Galactic center sources are coincident with 6.7GHz masers, and that 44% ± 17% of foreground sources are coincident with 6.7GHz masers. For 44GHz masers, we find correlation rates of 27% ± 13% and 25% ± 13% for Galactic center green sources and foreground green sources, respectively. Based on these CH3OH maser detection rates, as well as correlations of green sources with other tracers of star formation, such as 24 μm emission and infrared dark clouds (IRDCs), we find no significant difference between the green sources in the Galactic center and those foreground to it. This suggests that once the star formation process has begun, the environmental differences between the Galactic center region and the Galactic disk have little effect on its observational signatures. We do find, however, some evidence that may support a recent episode of star formation in the Galactic center region.
KW - Galaxy: center
KW - ISM: clouds
KW - ISM: molecules
KW - stars: formation
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U2 - 10.1088/0004-637X/733/1/42
DO - 10.1088/0004-637X/733/1/42
M3 - Article
AN - SCOPUS:79956311558
VL - 733
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1
M1 - 42
ER -