Cool Diffuse Atomic Hydrogen Gas HI

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Cool Diffuse Atomic Hydrogen GasHI

• Kelsey Hattam
• Astronomy 225

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Who went looking for it?Why?

• Map out our own galaxy
• Predicted in 1944
• Discover in 1952

Jan Oort
Hendrick Van de Hulst
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How does it work?
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What do we do now that we can detect it?

• If HI were the solution to dark matter what would
  we expect to find?

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In Reality
M(HI) (2.356x105) D2 ?SndV M(solar)
NGC 6946
NGC 2915
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Our Galaxies
HI accounts for only 8 of the detected dark
matter
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Sources
Pictures http//www.nrao.edu/imagegallery/php/leve
l3.php?id116 http//www.astron.nl/wsrt/WSRTproj/i
ndex.old.html http//antwrp.gsfc.nasa.gov/apod/ap9
80715.html http//antwrp.gsfc.nasa.gov/apod/ap0101
13.html Sources http//www.astro.queensu.ca/hanes
/p016/Notes/23._Gas_in_the_ISM.htmlradio http//w
ww.gb.nrao.edu/fgdocs/HI21cm/21cm.html http//www.
du.edu/jcalvert/phys/hydrogen.htm http//www.astr
onomynotes.com/ismnotes/s3.htmA1.2.2