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F. Wyrowski (UMD), S.J. Carey (BC), M.P. Egan (AFRL), P.A. Feldman, R.O. Redman (NRC/Canada)
We present high-angular-resolution observations of cold, dense condensations within a new population of infrared-dark clouds (IRDCs) identified during the MSX mid-infrared survey of the Galactic Plane (Egan et al.\ 1998, ApJL 494, 199). The observations were conducted with the Berkeley-Illinois-Maryland-Association interferometer (BIMA) in its B, C and D array configurations at 3mm. In all four observed sources we detected compact (<0.4 pc), slightly resolved, massive cores. In one case, the core is resolved into multiple components with sizes < 4000 AU. We will compare the 3mm continuum results with previous SCUBA imaging (Carey et al.\ 2000, ApJL, in press) to constrain dust properties and temperatures in the dark cloud cores.
Simultaneously, we obtained spectral line images of \rm N2H+~(1--0) toward the clouds. The agreement between \rm N2H+ and 850~\mum emission is almost perfect, confirming chemical models of prestellar cores, which predict little depletion of \rm N2H+ in these sources (Bergin & Langer 1997, ApJ 486, 316). Hence, \rm N2H+ is an ideal tool to investigate their kinematical characteristics complementary to SCUBA mapping of the mass distribution of the IRDCs.
FW is supported by the National Science Foundation under Grant No. 96-13716.
The author(s) of this abstract have provided an email address for comments about the abstract: wyrowski@astro.umd.edu