Detections of SiO and H${}_2$O Masers in the Bipolar Nebula IRAS 19312+1950

Abstract

We report on the detection of SiO and water masers toward a newly found bipolar nebula, IRAS 19312+1950. This object exhibits extreme red IRAS color log (F25/F12)=0.5 and log (F60/F25)=0.7 and a nebulosity having a size of about 30" extended to the South-West in the 2MASS near-infrared image. Toward this object, we have detected emission from the H2O 6(1,6)-5(2,3) transition, the SiO J=1-0, v=1 and 2, and J=2-1, v=1 transitions, and the SO 2(2)--1(1) and H13CN J=1-0 transitions. The thermal lines of SO and H13CN are shifted by about 12 km/s in radial velocity with respect to the maser lines, indicating that thermal emission comes from the background molecular cloud. However, the SiO J=2-1, v=2 spectrum shows another component of SiO emission separated by 26 km/s from the main component, that might be formed in a rotating or expanding shell.

arXiv comment5 peges including 1 table, and 2 jpeg figures. Accepted for PASJ (Publication of the Astronomical Society of Japan)

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• BIMA Array Observations of the Highly Unusual SiO Maser Source with a Bipolar Nebulosity, IRAS 19312+1950
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• Near-infrared polarimetric study of the bipolar nebula IRAS 19312+1950
• Methanol Observation of IRAS 19312+1950: A Possible New Type of Class I Methanol Masers
• Wide Field CO Mapping in the Region of IRAS 19312+1950
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