Structure and Composition of the Interstellar and Circumstellar Medium
The JCMT Gould Belt Survey: The free-free contribution to heating of the circumstellar medium
Damian Rumble
Jennifer Hatchell (University of Exeter)
University of Exeter
We present SCUBA-2 450 and 850 μm observations of Serpens-Aquila, part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey of nearby star-forming regions. Simulations suggest that radiative feedback influences the star formation process and we investigate observational evidence for this by constructing temperature maps. Maps are derived from the ratio of SCUBA-2 fluxes and a two-component model of the JCMT beam for a fixed dust opacity spectral index of β = 1.8. We find evidence that the fluxes of several OB stars forming in these regions are contaminated by free–free emission over a range of spectral indices indicative of ultracompact H II regions and polar wind/jet features. In the case of the Herbig star MWC 297, contamination accounts for 73 ± 5 per cent and 82 ± 4 per cent of peak flux at 450μm and 850 μm, respectively. The residual thermal disc of the star is almost undetectable at these wavelengths. Populations of YSOs are catalogued where SCUBA-2 850 μm clumps identified by the FELLWALKER algorithm coincide with Spitzer Gould Belt Survey detections. YSOs mass ranges from 0.1 to 5.1 M⊙ with a mean temperature of 15 ± 2 K. We observe a starless clump with an abnormally high mean temperature of 46 ± 2 K and conclude that it is radiatively heated by the star MWC 297. Jeans stability provides evidence that radiative heating by the star MWC 297 may be suppressing clump collapse.


09:00 - 10:30