Radio Science and PILOT

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Radio Science and PILOT

• Tony Wong
• ATNF/UNSW
• PILOT Workshop
• 26 March 2003

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New Synergies

• PILOT 2m, 1-30 ?m (10-300 THz). Starlight,
  thermal dust continuum, recombination lines,
  excited H2, PAH features.
• ATCA 6 x 22m, 1-105 GHz. HI, synchrotron,
  free-free emission, molecular masers, thermal
  molecular lines, dust continuum.
• ALMA (2010) 64 x 12m, 30-850 GHz. Thermal
  molecular lines, atomic fine-structure lines,
  dust continuum, recombination lines, CMB.
• IRQA (2010?) 0.1-0.2 GHz? Synchrotron,
  free-free absorption, redshifted HI.

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Radio-IR Astrometry

• Massive stars tend to form in clusters at great
  distances, and thus accurate astrometry is needed
  to make firm IDs.
• Since mid-IR sources are often invisible in the
  optical/NIR, astrometry must be performed by
  comparison with radio synthesis maps.
• Results can significantly affect interpretation!

Methanol masers (diamonds) on 18um OSCIR/Keck
contours, de Buizer et al. (2002)
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Mid-IR as a SFR indicator

• Relatively few galaxies have been imaged in the
  mid-IR (e.g. Roussel et al. 2001 with ISOCAM,
  10).
• Integrated mid-IR light is a combination of
  continuum from small grains and aromatic bands
  due to molecular aggregates (PAHs?).
• Potentially good tracer of massive star formation
  if excitation is dominated by HII regions.

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The mid-IR/radio correlation

• Gruppioni et al. (2003) have compared faint
  (mJy) 15µm sources detected by ISO (ELAIS-S1,
  S2) with 1.4 GHz ATCA imaging.
• Strong mid-IR/radio correlation, though not as
  tight as FIR/radio uncertain mid-IR
  K-corrections?

• Is PILOT sensitive enough to study this
  population?

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Summary

• Radio/submm observations of the ISM can
  complement PILOTs capabilities, especially in
  the mid-IR (4-30 µm).
• Large FOV facilitates astrometry with radio maps.
• Mid-IR a useful probe of star formation, both in
  nearby and distant galaxies.
• Circumstellar envelopes around AGB stars mass
  loss rates from CO line profiles, colours from
  mid-IR. LMC survey?
• Competition Spitzer, SOFIA, Herschel