H. Beuther, J. Tackenberg, H. Linz, Th. Henning, O. Krause, S. Ragan, M. Nielbock, R. Launhardt, A. Schmiedeke, F. Schuller, P. Carlhoff, Q. Nguyen-Luong, T. Sakai
Context: The earliest stages of high-mass star formation are still poorly
characterized. It is also unknown whether the initial conditions vary with
environment. Aims: We want to investigate the youngest massive gas clumps in
the environment of extremely active star formation. Methods: We selected the
IRDC18454 complex associated with the W43 Galactic mini-starburst, and observed
it in the continuum emission between 70mu and 1.2mm, and in spectral line
emission of N2H+ and 13CO with single-dish instruments and an interferometer.
Results: The multi-wavelength continuum study allows us to identify clumps that
are infrared dark even at 70mu and hence the best candidates to be genuine
high-mass starless gas clumps. The spectral energy distributions reveal
elevated temperatures and luminosities compared to more quiescent environments.
Furthermore, we identify a temperature gradient from the W43 mini-starburst
toward the starless clumps. We discuss whether the radiation impact of the
nearby mini-starburst changes the fragmentation properties of the gas clumps
and by that maybe favors more high-mass star formation in such an environment.
The spectral line data reveal two different velocity components of the gas at
100 and 50km/s. While chance projection is a possibility to explain these
components, the projected associations of the emission sources as well as the
prominent location at the Galactic bar -- spiral arm interface also allow the
possibility that these two components may be spatially associated and even
interacting. Conclusions: High-mass starless gas clumps can exist in the close
environment of very active star formation without being destroyed. The impact
of the active star formation sites may even allow for more high-mass stars to
form in these 2nd generation gas clumps.
View original:
http://arxiv.org/abs/1112.3543
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