MMB Followup Gary Fuller Jodrell Bank Centre for
MMB Follow-up Gary Fuller Jodrell Bank Centre for Astrophysics University of Manchester for the MMB collaboration
Masers Three common maser species H 2 O OH CH 3 OH – 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. 67 GHz Second brightest maser line known (after H 2 O)
Class II Methanol Masers Pumped by mid-infrared radiation High density High methanol abundance (>10 -8) made in grain mantles Dust temperatures ~100 -200 K Suggest regions where young star is heating its environment. Evaporating ice mantles from grains, releasing methanol in to gas. Hot core sources? Cragg et al. 2002
Methanol Multi. Beam 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: |b|<2 o Total area = 1440 sq. degrees Velocity coverage: ~150 km/s Sensitivity: 1 sigma noise level ~0. 2 Jy Positional accuracy: < 1'' Single dish survey with 7 beam receiver plus interferometric follow-up to determine positions
MMB status Southern hemisphere completed Noise level: rms<0. 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. 82 Jy 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)
MMB Sources All maser sources are YMSO But not all YMSO are CH 3 OH maser sources Large, interesting wide-spread (throughout Galaxy) sample But biased (by age/evolutionary status, environment ? )
Current Follow-up Projects Additional CH 3 OH 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: 22 GHz-45 GHz-90 GHz Science goal: Winds vs dust vs HII regions associated with maser sources - evolution and structure H 2 O 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 45 GHz proposal this coming round - 200 -400 sources – single point observations
Current Follow-up Projects An ATCA survey for highly excited NH 3 lines Science goals: Search for disks and hot cores NH 3 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 MPIf. R 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
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