Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 1H014

Observations of Infrared-identified Protostars in Molecular Maser Lines

Kang, Miju (Korea Astronomy and Space Science Institute)
Lee, Jeong-Eun (Kyung Hee University)
Choi, Minho (Korea Astronomy and Space Science Institute)
Choi, Yunhee (Kapteyn Astronomical Institute & SRON)
Kim, Kee-Tae (Korea Astronomy and Space Science Institute)
Di Francesco, James (National Research Council of Canada, Herzberg Institute of Astrophysics)
Park, Yong-Sun (Seoul National University)

Many protostars were recently identified from the infrared data from the Spitzer space telescope. We present the results of a maser survey toward 99 protostars in the Orion molecular cloud complex. Observations were carried out in the water maser line at 22 GH z and three class I methanol maser lines at 44, 95, and 133 GHz. Five water maser sources were detected, and they are excited by HH 1-2 VLA 3, HH 1-2 VLA1, L1641N MM1/3, NGC 2071 IRS 1/3, and an object in the OMC 3 region. The water masers showed significant variability in intensity and velocity with time scales of a month or shorter. Four methanol emission sources were detected, and those in the OMC 2 FIR 3/4 and L1641N MM1/3 regions are probably masers. The methanol emission from the other two sources in the NGC 2071 IRS 1-3 and V380 Ori NE regions are probably thermal. For the water maser, the number of detections per protostar in the survey region is about 2%, which suggests that the water maser of low-mass protostars is rarely detectable. Th e methanol class I maser of low-mass protostars is an even rarer phenomenon, with a detection rate much smaller than 1%.

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