boulanger by wuzhengqin


									    Gas and mm Dust emission

   François Boulanger et Guilaine Lagache
   (Institut d ’Astrophysique Spatiale, Orsay)

• Tracingdiffuse ISM components in te Solar
Neighborhood and across the Galaxy with mm
dust emission
• mm dust properties across the HI/H2 transition
                              Gas Tracers
• Diffuse H II : Pulsar dispersion measure
• H I : 21 cm Line
    > Misses cold H I
• H2 : CO low J rotational lines
    > several caveats: optical thickness, CO photo-dissociation
    > Misses « diffuse » H2 (seen in absorption and in gamma rays)
• Dust : H I and H2
    > Extinction: clumping
    > Far-IR emission per dust mass is temperature dependent
    > mm dust emission: Matter Tracer
          Galaxies and star forming cores (ground telescopes) <=> diffuse ISM
          Dust emissivity: How constant across the HII/HI/Diffuse H2/CO transitions?
IR-HI Correlation at 1.2mm

FIRAS + HI all-sky survey
Molecular Gas
Longitude Profile
 HI/H2 Transition
Solar Neighorhood

                     H2 self-shielding:
                     HI  H2 pour
                     NH> 5 1020 H/cm2

          Savage et al. 1977

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