1. 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)

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
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