VLA Observations of Carbon 91 α Recombination Line Emission in W 49 North
نویسندگان
چکیده
We have detected C91α (8.5891 GHz) emission toward 4 ultra-compact H ii regions (UCHs; W49G, J, L & C) in the W49 North massive star forming region with the Very Large Array (VLA) at 3 resolution. No carbon line emission was detected toward UCHs W49F, A, O, S and Q at this frequency to a 3σ level of 2 mJy. We also observed the same region in the C75α line (15.3 GHz) with no detection at a 3σ level of 6 mJy with a 1.7 beam. Detection of line emission toward these sources add supporting data to the earlier result of Roshi et al. (2005a) that many UCHs have an associated photo-dissociation region (PDR). Similarity of the LSR velocities of carbon recombination lines and H2CO absorption toward UCHs in W49 North suggests that the PDRs reside in the Deceased 29 October, 2001
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