MMB Followup

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MMB Follow-up

• Gary Fuller
• Jodrell Bank Centre for Astrophysics
• University of Manchester
• for the MMB collaboration

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Masers

• Three common maser species
• H2O
• OH
• CH3OH two types of maser sources/lines Class
  I and II
• All associated with young high mass stars
• But Class II methanol masers are ONLY associated
  with high mass sources
• - Less evolved than UCHII regions
• few have radio continuum emission
• peaks of dust continuum emission
• Strongest Class II maser line is at 6.67GHz
• Second brightest maser line known (after H2O)

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Class II Methanol Masers

• Pumped by mid-infrared radiation
• High density
• High methanol abundance (gt10-8)
• made in grain mantles
• Dust temperatures 100-200 K

Cragg et al. 2002
Suggest regions where young star is heating its
environment. Evaporating ice mantles from grains,
releasing methanol in to gas. Hot core sources?
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Methanol MultiBeam Survey(MMB) Parameters

• Survey full Galactic plane
• Complementary to a wide range of other surveys of
  the Galactic plane at radio continuum, infrared,
  millimetre and submillimetre wavelengths
• Latitude coverage blt2o
• Total area 1440 sq. degrees
• Velocity coverage 150 km/s
• Sensitivity 1 sigma noise level 0.2 Jy
• Positional accuracy lt 1''
• Single dish survey with 7 beam receiver plus
  interferometric follow-up to determine positions

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MMB status

• Southern hemisphere completed
• Noise level rmslt0.2 Jy
• Detection 2 stage process
• 80 complete at 0.8 Jy
• Compare to Pandian et al.
• 3-sigma limit 0.27 Jy
• Strongest non-detection 0.82Jy
• Next strongest 0.5 Jy
• Van der Walt MMB 80 to 85 complete
• 870 maser sources detected
• About 35 previously unknown
• Majority of new sources flux of few Jy
• (Plus about 80 Ex-OH sources)

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MMB Sources

• All maser sources are YMSO
• But not all YMSO are CH3OH maser sources
• Large, interesting wide-spread (throughout
  Galaxy) sample
• But biased (by age/evolutionary status,
  environment ?)

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Current Follow-up Projects

• Additional CH3OH maser lines
• Science goal Physics of masers as probes of
  environment
• OH Maser lines
• Science goal Magnetic fields
• Radio Continuum Follow-up with ATCA survey for
  HCHII regions 22GHz-45GHz-90GHz
• Science goal Winds vs dust vs HII regions
  associated with maser sources - evolution and
  structure
• H2O maser imaging at ATCA
• Science goal Maser-source evolution tracing
  outflows from sources
• Search for Outflows
• Currently northern sources observed with JCMT
• Molecular environment
• Science goal Molecular environment/chemical
  evolution
• Mopra survey 45GHz proposal this coming round -
  200-400 sources single point observations

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Current Follow-up Projects

• An ATCA survey for highly excited NH3 lines
• Science goals Search for disks and hot cores
• NH3 survey of core properties
• Science goals Properties of cores containing
  maser sources
• Cross correlation with Spitzer Dark Clouds (SDCs)
• Statistics Galactic distribution
• Distance calculations, HISA, luminosity
  distributions, l-v,
• ATLASGAL cross-correlation
• Being done in collaboration with MPIfR Bonn
• High resolution IR (M) spectroscopic observations
• Higher angular resolution L and M imaging
• Science goals structure of the circumstellar
  environment - link with outflows green fuzzies