Water Masers Associated with Infrared Dark Cloud Cores

• Published in: The Astrophysical journal 2006-11, Vol.651 (2), p.L125-L128
• Main Authors: Wang, Yang, Zhang, Qizhou, Rathborne, Jill M, Jackson, James, Wu, Yuefang
• Format: Article
• Language: English
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology
• ISSN: 1538-4357; 0004-637X; 1538-4357
• DOI: 10.1086/508939

We present a survey of the 6 sub(16)-5 sub(23) H sub(2)O maser transition toward a sample of 140 compact cores in infrared dark clouds using the Very Large Array. Strong (>1 Jy) H sub(2)O maser emission was found associated with 17 cores, indicative of star formation in these cores. We infer that the cores with H sub(2)O masers have embedded protostars. Cores associated with maser emission have masses of 12 to 2 x 10 super(3) M sub( ), similar to the mass range in the entire sample. The H sub(2)O maser detection rate (12%) toward the compact, cold cores is much lower than that toward high-mass protostellar objects and ultracompact H II regions. The detection rate of H sub(2)O masers is significantly higher for higher mass cores than for lower mass cores. We suggest that some of the most massive infrared dark cloud cores without H sub(2)O maser emission are at an evolutionary stage earlier than the protostellar phases. They are prime candidates for high-mass starless cores.