Site Map
Contacts
Follow us on Facebook Follow us on Twitter YouTube channel
Centro de Astrofísica da Universidade do Porto

WFCAM, Spitzer/IRAC and SCUBA observations of the massive star-forming region DR21/W75 I. The collimated molecular jets

C. J. Davis, M. S. N. Kumar, G. Sandell, D. Froebrich, M. D. Smith, M.J. Currie, J. Ballot

Abstract
We present wide-field near-infrared (IR) images of the DR21/W75 high-mass star-forming region, obtained with the Wide Field Camera (WFCAM) on the United Kingdom Infrared Telescope. Broad-band JHK and narrow-band H2 1-0S(1) images are compared to archival mid-IR images from the Spitzer Space Telescope, and 850-μm dust-continuum maps obtained with the Submillimeter Common User Bolometer Array (SCUBA). Together these data give a complete picture of dynamic star formation across this extensive region, which includes at least four separate star-forming sites in various stages of evolution. The H2 data reveal knots and bow shocks associated with more than 50 individual flows. Most are well collimated, and at least five qualify as parsec-scale flows. Most appear to be driven by embedded, low-mass protostars. The orientations of the outflows, particularly from the few higher mass sources in the region (DR21, DR21(OH), W75N and ERO 1), show some degree of order, being preferentially orientated roughly orthogonal to the chain of dusty cores that runs north�south through DR21. Clustering may inhibit disc accretion and therefore the production of outflows; we certainly do not see enhanced outflow activity from clusters of protostars. Finally, although the low-mass protostellar outflows are abundant and widely distributed, the current generation does not provide sufficient momentum and kinetic energy to account for the observed turbulent motions in the DR21/W75 giant molecular clouds. Rather, multiple epochs of outflow activity are required over the million-year time-scale for turbulent decay.

Monthly Notices of the Royal Astronomical Society
Volume 374, Page 29
January 2007

>> PDF>> DOI

Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

Proceed on CAUP's website|Go to IA website