Spitzer Mid-IR Extinction

Short science presentation for the STScI MIRI Team.

Transcript

1. Spitzer mid-IR Extinction
   Karl D. Gordon
   Astronomer
   MIRI Inst. Scientist
   MIRI Tagup
   5 Oct 2021
   kgordon@stsci.edu
   @karllark2000
   karllark@github
   Gordon et al. 2021, ApJ, 916, 33
   

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2. Pair Method for Extinction I
   Github: measure_extinction
   

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3. Pair Method for Extinction I
   

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4. Diffuse Extinction Curve
   

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5. Sample of OB stars
   

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7. Analytic Fit
   

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9. Dense = 3 micron
   ice feature
   not by A(V) threshold
   

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10. Two Dense Curves
    

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11. Lower than most literature results
    

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12. Higher than dust grain models
    

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13. Selected correlations (or not)
    

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14. No other features
    

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15. G21 in dust_extinction
    Github: dust_extinction
    

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16. NIR Extinction
    work by Marjorie Decleir (ISM* postdoc)
    

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17. Challenging from the ground
    

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18. JWST cycle 1 programs
    ●
    S. Zeegers: 12 sightlines (ID:2183)
    – Galactic plane, 3 different regions
    ●
    M. Decleir: 9 sightlines (ID:2459)
    – All also have HST UV depletions (current cycle), FUSE H2, IUE HI, FUSE/IUE
    extinctions
    ●
    Both use NIRCam TSO grism and MIRI MRS
    – cover 2.4-28 microns
    – measure the 3.4 micron HAC feature and 10 & 20 micron silicate features (and any
    other features)
    – measure the continuum extinction over the full range
    

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