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标题：Discovery of 22 GHz Water Masers in the Serpens South Region
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作者：Gisela N.Ortiz-León ; Adele L.Plunkett ; Laurent Loinard 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2021
卷号：162
期号：2
页码：1-17
DOI：10.3847/1538-3881/ac052c
语种：English
出版社：American Institute of Physics
摘要：Using the Karl G. Jansky Very Large Array (VLA), we have conducted a survey for 22 GHz, 61,6–52,3 H2O masers toward the Serpens South region. The masers were also observed with the Very Long Baseline Array following the VLA detections. We detect for the first time H2O masers in the Serpens South region that are found to be associated to three Class 0–Class I objects, including the two brightest protostars in the Serpens South cluster, known as CARMA-6 and CARMA-7. We also detect H2O masers associated to a source with no outflow or jet features. We suggest that this source is most probably a background asymptotic giant branch star projected in the direction of Serpens South. The spatial distribution of the emission spots suggest that the masers in the three Class 0–Class I objects emerge very close to the protostars and are likely excited in shocks driven by the interaction between a protostellar jet and the circumstellar material. Based on the comparison of the distributions of bolometric luminosity of sources hosting 22 GHz H2O masers and 162 young stellar objects covered by our observations, we identify a limit of LBol ≈ 10L⊙ for a source to host water masers. However, the maser emission shows strong variability in both intensity and velocity spread, and therefore masers associated to lower-luminosity sources may have been missed by our observations. We also report 11 new sources with radio continuum emission at 22 GHz.