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A new thermometer for external galaxies

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Abstract

We introduce a new spectroscopic method at radio frequencies to measure the temperature of giant cloud complexes in external galaxies. We have detected the λ = 1.3 cm J, K = 2, 2 inversion transition of NH3 in the nucleus of the galaxy IC342. This result, taken together with our previous detection of the J, K = 1, 1 transition1 allows us to deduce a kinetic temperature of 50±15 K and an equivalent size scale of at least 25 pc for the molecular gas. The results are consistent with line formation in the nucleus where very active star formation is taking place.

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References

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Authors and Affiliations

  1. Max-Planck-Institut für Radioastronomie, D-5300, Bonn, 1, FRG

    Robert N. Martin & K. Ruf

  2. Radio Astronomy Laboratory, University of California, Berkeley, California, 94720, USA

    Paul T. P. Ho

Authors
  1. Robert N. Martin
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  2. Paul T. P. Ho
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  3. K. Ruf
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Martin, R., Ho, P. & Ruf, K. A new thermometer for external galaxies. Nature 296, 632–633 (1982). https://doi.org/10.1038/296632a0

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  • DOI: https://doi.org/10.1038/296632a0

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