The Spin Temperature of the Interstellar Neutral Hydrogen
- 1 March 1969
- journal article
- other
- Published by Cambridge University Press (CUP) in Publications of the Astronomical Society of Australia
- Vol. 1 (5) , 215-216
- https://doi.org/10.1017/s1323358000011589
Abstract
The lack of any direct measurements on the spin temperature of the neutral hydrogen in the Galaxy has led to considerable controversy in the past. Estimates of the temperature have depended strongly on whether they are based on emission or absorption studies. The widely accepted value of 125°K based on emission studies dates back to Schmidt. He adopted this figure on the premise that the maximum observed brightness temperatures in the galactic plane were in directions of high optical depth. The brightness temperature was then equated with the spin temperature on the assumption that the temperature did not fluctuate very much in a large region around the Sun.Keywords
This publication has 3 references indexed in Scilit:
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- A High Resolution Investigation of 21 cm Absorption SpectraMonthly Notices of the Royal Astronomical Society, 1964
- The Hydrogen Line in Absorption.The Astrophysical Journal, 1962