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e-MERLIN Key Project on Massive Star Formation

School of Physics & Astronomy FACULTY OF MATHEMATICS & PHYSICAL SCIENCES. e-MERLIN Key Project on Massive Star Formation. Melvin Hoare Jim Jackson (Boston University) Gary Fuller (University of Manchester) Janet Drew (Imperial College London). Why Massive Star Formation?.

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e-MERLIN Key Project on Massive Star Formation

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  1. School of Physics & Astronomy FACULTY OF MATHEMATICS & PHYSICAL SCIENCES e-MERLIN Key Project on Massive Star Formation Melvin Hoare Jim Jackson (Boston University) Gary Fuller (University of Manchester) Janet Drew (Imperial College London)

  2. Why Massive Star Formation? • Underpins much of astrophysics • Pop III & Primeval galaxies • Starbursts • Galaxy evolution • Feedback, Superwinds, Chemical evolution • Extreme environments • SNe, GRBs • NS, BH Gemini Observatory - GMOS Team

  3. Key Unsolved Questions • What determines the upper IMF? • Accretion physics? • Outflow physics? • Evolutionary scheme?

  4. Accretion Physics • Magnetically/turbulently controlled collapse or triggering? IRAM 30m 13CO 1-0 map Spitzer 8mm image Krumholz et al. (2005)

  5. Outflow Physics • Radiation or magnetically driven winds and outflows? X-wind (Shu et al. 1997) or disk wind (Ouyed et al. 2003) Drew et al. (1998); Proga (2000)

  6. Outflow Physics • Bipolar or cometary at the onset of the H II region phase NGC 7538 IRS 1

  7. Evolutionary Scheme Massive pre-stellar core Inactive IR Dark Cloud Active IR Dark Cloud Methanol masers Hot molecular core Massive young stellar object Water masers Hyper-compact H II region Ultra-compact H II region OB cluster

  8. Context • Exploitation of Galactic Plane surveys at a range of wavelengths – many UK led • Build on discoveries made with MERLIN and the VLA • Currently only a few bright/nearby examples of the later stages have been studied

  9. Equatorial Winds and Jets Blue/red contours 8/22 GHz VLA map Image: SMA 850mm dust continuum MERLIN 5 GHz 0.1" (image) 2mm speckle 0.2" (contours) Patel et al. (2005) Hoare (2002)

  10. Galactic Plane Surveys

  11. Key Project Sample • Well selected sub-samples from the surveys that cover a range of masses and evolutionary stages UCHIIs Transition objects? MYSOs HMCs/IRDCs

  12. Key Project Outline • Active IR Dark Clouds from GLIMPSE/MIPSGAL/GRS • Methanol maser sources from Arecibo/MMB • Massive YSOs from Red MSX Source survey • Herbig Be stars from IPHAS • UCHII regions from CORNISH survey • Distance limited samples (e.g. < 7 kpc) to preserve physical spatial resolution

  13. Key Project Outline • 20/40 from each category for full/half tracks at 4-8 GHz • 1/16th BW on the methanol maser 6.7 GHz line • Including Lovell gives 2-3 mJy/beam noise level • 1000 hours in total

  14. Why Key Project? • Avoid piecemeal approach through PI programmes • Good sample selection only way to unlock evolutionary trends • Builds co-operation between Galactic Plane survey teams • Pools expertise within these teams • Will answer key questions • Onset of wind and H II region phases • Driving mechanisms

  15. Low-Mass YSO Key Project WFPC2 NICMOS VLA 8 GHz

  16. Stellar Jets • Key tests of MHD driving mechanisms Shang et al. (2002; 2004) 6/1.5 AU resolution at 140 pc

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