EPoS Contribution
EPoS Contribution
Feedback of massive star formation: from simulations to observations

Anna McLeod
ESO, Garching b. Muenchen, DE
Massive stars and star clusters have great impact on their immediate surroundings: via their strong stellar winds and radiation they are able to shape and deplete the surrounding molecular clouds they originally formed from, and are thought to be the cause of new star formation at the rim of these clouds. The feedback mechanisms have been modeled with powerful smoothed particle hydrodynamic simulations, showing, for instance, that radiation from massive clusters clears bubble-shaped gas voids exposing pillar-like structures, reduces the overall star formation rate and affects the geometrical distribution of stars in the vicinity. Thanks to the high resolution of modern day telescopes, it is possible to directly observe the results of the feedback of massive star formation. While many of the features observed in numerical simulations are in qualitative agreement with the observed morphology of massive star forming complexes, a detailed quantitative comparison is lacking. Detailed one-to-one matching of simulations and data is impractical, due to the complexity of the regions, but the new libraries of numerical simulations make statistical comparisons possible. Large scale multi wavelength surveys of the Milky Way provide a census of high mass star forming regions with different characteristics (e.g. total mass, evolutionary state, spatial distribution of star forming sites), and can be used to statistically validate the predictions of numerical simulations that incorporate different prescriptions for the effects of feedback. We are using the extensive library of numerical simulations of high-mass star formation with feedback assembled by Dale et al. to extract time dependent observable parameters (stellar luminosity function, cold gas reservoire, hot/ionized gas content, momentum input into the parental cloud, etc.) to be compared with the observational data. Additionally, we will exploit the K-band Multi-Object Spectrograph (KMOS) mounted on the VLT and its unique capability of 3D spectroscopy in the near-infrared, and will then combine the data with a multi-wavelength approach to compile a thorough quantitative comparison between simulations and observations.
Caption: Distribution of young stars in an active star forming region. Left: source distribution in the W5 region on a Spitzer MIPS 24 micron grey-scale image, from Koenig et al. 2008, ApJ 688:1142-1158; red, green and yellow objects are Class I, Class II and transition disk candidates respectively, asterisks mark O stars. Right: result of a simulation including ionizing feedback in a cloud with initially 104 Msol (courtesy of J. Dale); the grey-scale indicates gas column density, circles indicate spontaneously formed sink particles, triangles are triggered sink particles; in blue are ionizing sources (M > 20 Msol), yellow objects are objects with negligible accretion rates, and green and red objects are Class I and Class II sources respectively.
Collaborators:
L. Testi, ESO, Germany
J. Dale, USM, Germany
A. Ginsburg, ESO, Germany
S. Ramsay, ESO, Germany
Suggested Session: Massive Star Formation and Feedback