Simultaneous observations of SiO and H_2O masers toward known stellar SiO and/or H_2O maser sources

摘要

We present the results of simultaneous observations of SiO v = 1, 2, ~(29)SiO v = 0, J = 1?0 and H_2O 6_(16)-5_(23) maser lines toward 318 known stellar SiO and/or H_2O maser sources using the Yonsei 21-m radio telescope of the Korean VLBI Network. Toward 166 known SiO and H_2O maser sources, both SiO and H_2O maser emissions were detected from 112 sources giving a detection rate of 67.5 %. On the other hand, toward 152 known H_2O-only maser sources, both SiO and H_2O maser emissions were detected from 62 sources, giving a detection rate of 40.8 %. Characteristics of all observed sources in the IRAS two-color diagram is investigated including their evolutionary sequence and mutual relations between SiO and H_2O maser properties.